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-rw-r--r--Makefile.objs1
-rw-r--r--default-configs/pci.mak1
-rw-r--r--docs/usb2.txt38
-rw-r--r--hw/bt-hid.c6
-rw-r--r--hw/esp.c119
-rw-r--r--hw/lsi53c895a.c200
-rw-r--r--hw/pci_ids.h1
-rw-r--r--hw/scsi-bus.c220
-rw-r--r--hw/scsi-disk.c271
-rw-r--r--hw/scsi-generic.c223
-rw-r--r--hw/scsi.h91
-rw-r--r--hw/spapr_vscsi.c187
-rw-r--r--hw/usb-bt.c6
-rw-r--r--hw/usb-ccid.c4
-rw-r--r--hw/usb-desc.c56
-rw-r--r--hw/usb-desc.h24
-rw-r--r--hw/usb-ehci.c2037
-rw-r--r--hw/usb-hid.c9
-rw-r--r--hw/usb-hub.c9
-rw-r--r--hw/usb-msd.c140
-rw-r--r--hw/usb-musb.c2
-rw-r--r--hw/usb-net.c6
-rw-r--r--hw/usb-ohci.c4
-rw-r--r--hw/usb-serial.c7
-rw-r--r--hw/usb-uhci.c6
-rw-r--r--hw/usb-wacom.c7
-rw-r--r--hw/usb.c101
-rw-r--r--hw/usb.h40
-rw-r--r--hw/virtio-console.c47
-rw-r--r--hw/virtio-serial-bus.c83
-rw-r--r--hw/virtio-serial.h11
-rw-r--r--trace-events8
-rw-r--r--usb-bsd.c1
-rw-r--r--usb-linux.c444
34 files changed, 3379 insertions, 1031 deletions
diff --git a/Makefile.objs b/Makefile.objs
index 4478c61e0c..90838f6a0d 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -193,6 +193,7 @@ hw-obj-$(CONFIG_PCSPK) += pcspk.o
 hw-obj-$(CONFIG_PCKBD) += pckbd.o
 hw-obj-$(CONFIG_USB_UHCI) += usb-uhci.o
 hw-obj-$(CONFIG_USB_OHCI) += usb-ohci.o
+hw-obj-$(CONFIG_USB_EHCI) += usb-ehci.o
 hw-obj-$(CONFIG_FDC) += fdc.o
 hw-obj-$(CONFIG_ACPI) += acpi.o acpi_piix4.o
 hw-obj-$(CONFIG_APM) += pm_smbus.o apm.o
diff --git a/default-configs/pci.mak b/default-configs/pci.mak
index 0471efbcd8..22bd3502d4 100644
--- a/default-configs/pci.mak
+++ b/default-configs/pci.mak
@@ -3,6 +3,7 @@ CONFIG_VIRTIO_PCI=y
 CONFIG_VIRTIO=y
 CONFIG_USB_UHCI=y
 CONFIG_USB_OHCI=y
+CONFIG_USB_EHCI=y
 CONFIG_NE2000_PCI=y
 CONFIG_EEPRO100_PCI=y
 CONFIG_PCNET_PCI=y
diff --git a/docs/usb2.txt b/docs/usb2.txt
new file mode 100644
index 0000000000..b283c138e0
--- /dev/null
+++ b/docs/usb2.txt
@@ -0,0 +1,38 @@
+
+USB 2.0 Quick Start
+===================
+
+The QEMU EHCI Adapter does *not* support companion controllers.  That
+implies there are two completely separate USB busses: One USB 1.1 bus
+driven by the UHCI controller and one USB 2.0 bus driven by the EHCI
+controller.  Devices must be attached to the correct controller
+manually.
+
+The '-usb' switch will make qemu create the UHCI controller as part of
+the PIIX3 chipset.  The USB 1.1 bus will carry the name "usb.0".
+
+You can use the standard -device switch to add a EHCI controller to
+your virtual machine.  It is strongly recommended to specify an ID for
+the controller so the USB 2.0 bus gets a individual name, for example
+'-device usb-ehci,id=ehci".  This will give you a USB 2.0 bus named
+"ehci.0".
+
+I strongly recomment to also use -device to attach usb devices because
+you can specify the bus they should be attached to this way.  Here is
+a complete example:
+
+    qemu -M pc ${otheroptions}                           \
+        -drive if=none,id=usbstick,file=/path/to/image   \
+        -usb                                             \
+        -device usb-ehci,id=ehci                         \
+        -device usb-tablet,bus=usb.0                     \
+        -device usb-storage,bus=ehci.0,drive=usbstick
+
+This attaches a usb tablet to the UHCI adapter and a usb mass storage
+device to the EHCI adapter.
+
+enjoy,
+  Gerd
+
+--
+Gerd Hoffmann <kraxel@redhat.com>
diff --git a/hw/bt-hid.c b/hw/bt-hid.c
index abdfd35e86..09120af074 100644
--- a/hw/bt-hid.c
+++ b/hw/bt-hid.c
@@ -323,7 +323,7 @@ static void bt_hid_control_transaction(struct bt_hid_device_s *s,
             break;
         }
         s->proto = parameter;
-        s->usbdev->info->handle_control(s->usbdev, SET_PROTOCOL, s->proto, 0, 0,
+        s->usbdev->info->handle_control(s->usbdev, NULL, SET_PROTOCOL, s->proto, 0, 0,
                                         NULL);
         ret = BT_HS_SUCCESSFUL;
         break;
@@ -333,7 +333,7 @@ static void bt_hid_control_transaction(struct bt_hid_device_s *s,
             ret = BT_HS_ERR_INVALID_PARAMETER;
             break;
         }
-        s->usbdev->info->handle_control(s->usbdev, GET_IDLE, 0, 0, 1,
+        s->usbdev->info->handle_control(s->usbdev, NULL, GET_IDLE, 0, 0, 1,
                         s->control->sdu_out(s->control, 1));
         s->control->sdu_submit(s->control);
         break;
@@ -346,7 +346,7 @@ static void bt_hid_control_transaction(struct bt_hid_device_s *s,
 
         /* We don't need to know about the Idle Rate here really,
          * so just pass it on to the device.  */
-        ret = s->usbdev->info->handle_control(s->usbdev,
+        ret = s->usbdev->info->handle_control(s->usbdev, NULL,
                         SET_IDLE, data[1], 0, 0, NULL) ?
                 BT_HS_SUCCESSFUL : BT_HS_ERR_INVALID_PARAMETER;
         /* XXX: Does this generate a handshake? */
diff --git a/hw/esp.c b/hw/esp.c
index fa9d2a2706..6d3f5d239b 100644
--- a/hw/esp.c
+++ b/hw/esp.c
@@ -61,10 +61,11 @@ struct ESPState {
     int32_t ti_size;
     uint32_t ti_rptr, ti_wptr;
     uint8_t ti_buf[TI_BUFSZ];
-    uint32_t sense;
+    uint32_t status;
     uint32_t dma;
     SCSIBus bus;
     SCSIDevice *current_dev;
+    SCSIRequest *current_req;
     uint8_t cmdbuf[TI_BUFSZ];
     uint32_t cmdlen;
     uint32_t do_cmd;
@@ -187,6 +188,17 @@ static void esp_dma_enable(void *opaque, int irq, int level)
     }
 }
 
+static void esp_request_cancelled(SCSIRequest *req)
+{
+    ESPState *s = DO_UPCAST(ESPState, busdev.qdev, req->bus->qbus.parent);
+
+    if (req == s->current_req) {
+        scsi_req_unref(s->current_req);
+        s->current_req = NULL;
+        s->current_dev = NULL;
+    }
+}
+
 static uint32_t get_cmd(ESPState *s, uint8_t *buf)
 {
     uint32_t dmalen;
@@ -209,7 +221,7 @@ static uint32_t get_cmd(ESPState *s, uint8_t *buf)
 
     if (s->current_dev) {
         /* Started a new command before the old one finished.  Cancel it.  */
-        s->current_dev->info->cancel_io(s->current_dev, 0);
+        scsi_req_cancel(s->current_req);
         s->async_len = 0;
     }
 
@@ -232,7 +244,8 @@ static void do_busid_cmd(ESPState *s, uint8_t *buf, uint8_t busid)
 
     DPRINTF("do_busid_cmd: busid 0x%x\n", busid);
     lun = busid & 7;
-    datalen = s->current_dev->info->send_command(s->current_dev, 0, buf, lun);
+    s->current_req = scsi_req_new(s->current_dev, 0, lun);
+    datalen = scsi_req_enqueue(s->current_req, buf);
     s->ti_size = datalen;
     if (datalen != 0) {
         s->rregs[ESP_RSTAT] = STAT_TC;
@@ -240,11 +253,10 @@ static void do_busid_cmd(ESPState *s, uint8_t *buf, uint8_t busid)
         s->dma_counter = 0;
         if (datalen > 0) {
             s->rregs[ESP_RSTAT] |= STAT_DI;
-            s->current_dev->info->read_data(s->current_dev, 0);
         } else {
             s->rregs[ESP_RSTAT] |= STAT_DO;
-            s->current_dev->info->write_data(s->current_dev, 0);
         }
+        scsi_req_continue(s->current_req);
     }
     s->rregs[ESP_RINTR] = INTR_BS | INTR_FC;
     s->rregs[ESP_RSEQ] = SEQ_CD;
@@ -306,8 +318,8 @@ static void handle_satn_stop(ESPState *s)
 
 static void write_response(ESPState *s)
 {
-    DPRINTF("Transfer status (sense=%d)\n", s->sense);
-    s->ti_buf[0] = s->sense;
+    DPRINTF("Transfer status (status=%d)\n", s->status);
+    s->ti_buf[0] = s->status;
     s->ti_buf[1] = 0;
     if (s->dma) {
         s->dma_memory_write(s->dma_opaque, s->ti_buf, 2);
@@ -370,53 +382,56 @@ static void esp_do_dma(ESPState *s)
     else
         s->ti_size -= len;
     if (s->async_len == 0) {
-        if (to_device) {
-            // ti_size is negative
-            s->current_dev->info->write_data(s->current_dev, 0);
-        } else {
-            s->current_dev->info->read_data(s->current_dev, 0);
-            /* If there is still data to be read from the device then
-               complete the DMA operation immediately.  Otherwise defer
-               until the scsi layer has completed.  */
-            if (s->dma_left == 0 && s->ti_size > 0) {
-                esp_dma_done(s);
-            }
+        scsi_req_continue(s->current_req);
+        /* If there is still data to be read from the device then
+           complete the DMA operation immediately.  Otherwise defer
+           until the scsi layer has completed.  */
+        if (to_device || s->dma_left != 0 || s->ti_size == 0) {
+            return;
         }
-    } else {
-        /* Partially filled a scsi buffer. Complete immediately.  */
-        esp_dma_done(s);
     }
+
+    /* Partially filled a scsi buffer. Complete immediately.  */
+    esp_dma_done(s);
 }
 
-static void esp_command_complete(SCSIBus *bus, int reason, uint32_t tag,
-                                 uint32_t arg)
+static void esp_command_complete(SCSIRequest *req, uint32_t status)
 {
-    ESPState *s = DO_UPCAST(ESPState, busdev.qdev, bus->qbus.parent);
+    ESPState *s = DO_UPCAST(ESPState, busdev.qdev, req->bus->qbus.parent);
 
-    if (reason == SCSI_REASON_DONE) {
-        DPRINTF("SCSI Command complete\n");
-        if (s->ti_size != 0)
-            DPRINTF("SCSI command completed unexpectedly\n");
-        s->ti_size = 0;
-        s->dma_left = 0;
-        s->async_len = 0;
-        if (arg)
-            DPRINTF("Command failed\n");
-        s->sense = arg;
-        s->rregs[ESP_RSTAT] = STAT_ST;
-        esp_dma_done(s);
+    DPRINTF("SCSI Command complete\n");
+    if (s->ti_size != 0) {
+        DPRINTF("SCSI command completed unexpectedly\n");
+    }
+    s->ti_size = 0;
+    s->dma_left = 0;
+    s->async_len = 0;
+    if (status) {
+        DPRINTF("Command failed\n");
+    }
+    s->status = status;
+    s->rregs[ESP_RSTAT] = STAT_ST;
+    esp_dma_done(s);
+    if (s->current_req) {
+        scsi_req_unref(s->current_req);
+        s->current_req = NULL;
         s->current_dev = NULL;
-    } else {
-        DPRINTF("transfer %d/%d\n", s->dma_left, s->ti_size);
-        s->async_len = arg;
-        s->async_buf = s->current_dev->info->get_buf(s->current_dev, 0);
-        if (s->dma_left) {
-            esp_do_dma(s);
-        } else if (s->dma_counter != 0 && s->ti_size <= 0) {
-            /* If this was the last part of a DMA transfer then the
-               completion interrupt is deferred to here.  */
-            esp_dma_done(s);
-        }
+    }
+}
+
+static void esp_transfer_data(SCSIRequest *req, uint32_t len)
+{
+    ESPState *s = DO_UPCAST(ESPState, busdev.qdev, req->bus->qbus.parent);
+
+    DPRINTF("transfer %d/%d\n", s->dma_left, s->ti_size);
+    s->async_len = len;
+    s->async_buf = scsi_req_get_buf(req);
+    if (s->dma_left) {
+        esp_do_dma(s);
+    } else if (s->dma_counter != 0 && s->ti_size <= 0) {
+        /* If this was the last part of a DMA transfer then the
+           completion interrupt is deferred to here.  */
+        esp_dma_done(s);
     }
 }
 
@@ -678,7 +693,7 @@ static const VMStateDescription vmstate_esp = {
         VMSTATE_UINT32(ti_rptr, ESPState),
         VMSTATE_UINT32(ti_wptr, ESPState),
         VMSTATE_BUFFER(ti_buf, ESPState),
-        VMSTATE_UINT32(sense, ESPState),
+        VMSTATE_UINT32(status, ESPState),
         VMSTATE_UINT32(dma, ESPState),
         VMSTATE_BUFFER(cmdbuf, ESPState),
         VMSTATE_UINT32(cmdlen, ESPState),
@@ -714,6 +729,12 @@ void esp_init(target_phys_addr_t espaddr, int it_shift,
     *dma_enable = qdev_get_gpio_in(dev, 1);
 }
 
+static const struct SCSIBusOps esp_scsi_ops = {
+    .transfer_data = esp_transfer_data,
+    .complete = esp_command_complete,
+    .cancel = esp_request_cancelled
+};
+
 static int esp_init1(SysBusDevice *dev)
 {
     ESPState *s = FROM_SYSBUS(ESPState, dev);
@@ -728,7 +749,7 @@ static int esp_init1(SysBusDevice *dev)
 
     qdev_init_gpio_in(&dev->qdev, esp_gpio_demux, 2);
 
-    scsi_bus_new(&s->bus, &dev->qdev, 0, ESP_MAX_DEVS, esp_command_complete);
+    scsi_bus_new(&s->bus, &dev->qdev, 0, ESP_MAX_DEVS, &esp_scsi_ops);
     return scsi_bus_legacy_handle_cmdline(&s->bus);
 }
 
diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
index 2ce38a97ae..83084b6b6a 100644
--- a/hw/lsi53c895a.c
+++ b/hw/lsi53c895a.c
@@ -174,6 +174,7 @@ do { fprintf(stderr, "lsi_scsi: error: " fmt , ## __VA_ARGS__);} while (0)
 #define LSI_TAG_VALID     (1 << 16)
 
 typedef struct lsi_request {
+    SCSIRequest *req;
     uint32_t tag;
     uint32_t dma_len;
     uint8_t *dma_buf;
@@ -567,11 +568,9 @@ static void lsi_do_dma(LSIState *s, int out)
     s->csbc += count;
     s->dnad += count;
     s->dbc -= count;
-
-    if (s->current->dma_buf == NULL) {
-        s->current->dma_buf = dev->info->get_buf(dev, s->current->tag);
+     if (s->current->dma_buf == NULL) {
+        s->current->dma_buf = scsi_req_get_buf(s->current->req);
     }
-
     /* ??? Set SFBR to first data byte.  */
     if (out) {
         cpu_physical_memory_read(addr, s->current->dma_buf, count);
@@ -581,13 +580,7 @@ static void lsi_do_dma(LSIState *s, int out)
     s->current->dma_len -= count;
     if (s->current->dma_len == 0) {
         s->current->dma_buf = NULL;
-        if (out) {
-            /* Write the data.  */
-            dev->info->write_data(dev, s->current->tag);
-        } else {
-            /* Request any remaining data.  */
-            dev->info->read_data(dev, s->current->tag);
-        }
+        scsi_req_continue(s->current->req);
     } else {
         s->current->dma_buf += count;
         lsi_resume_script(s);
@@ -652,82 +645,123 @@ static void lsi_reselect(LSIState *s, lsi_request *p)
     }
 }
 
-/* Record that data is available for a queued command.  Returns zero if
-   the device was reselected, nonzero if the IO is deferred.  */
-static int lsi_queue_tag(LSIState *s, uint32_t tag, uint32_t arg)
+static lsi_request *lsi_find_by_tag(LSIState *s, uint32_t tag)
 {
     lsi_request *p;
 
     QTAILQ_FOREACH(p, &s->queue, next) {
         if (p->tag == tag) {
-            if (p->pending) {
-                BADF("Multiple IO pending for tag %d\n", tag);
-            }
-            p->pending = arg;
-            /* Reselect if waiting for it, or if reselection triggers an IRQ
-               and the bus is free.
-               Since no interrupt stacking is implemented in the emulation, it
-               is also required that there are no pending interrupts waiting
-               for service from the device driver. */
-            if (s->waiting == 1 ||
-                (lsi_irq_on_rsl(s) && !(s->scntl1 & LSI_SCNTL1_CON) &&
-                 !(s->istat0 & (LSI_ISTAT0_SIP | LSI_ISTAT0_DIP)))) {
-                /* Reselect device.  */
-                lsi_reselect(s, p);
-                return 0;
-            } else {
-                DPRINTF("Queueing IO tag=0x%x\n", tag);
-                p->pending = arg;
-                return 1;
-            }
+            return p;
         }
     }
-    BADF("IO with unknown tag %d\n", tag);
-    return 1;
+
+    return NULL;
+}
+
+static void lsi_request_cancelled(SCSIRequest *req)
+{
+    LSIState *s = DO_UPCAST(LSIState, dev.qdev, req->bus->qbus.parent);
+    lsi_request *p;
+
+    if (s->current && req == s->current->req) {
+        scsi_req_unref(req);
+        qemu_free(s->current);
+        s->current = NULL;
+        return;
+    }
+
+    p = lsi_find_by_tag(s, req->tag);
+    if (p) {
+        QTAILQ_REMOVE(&s->queue, p, next);
+        scsi_req_unref(req);
+        qemu_free(p);
+    }
 }
 
-/* Callback to indicate that the SCSI layer has completed a transfer.  */
-static void lsi_command_complete(SCSIBus *bus, int reason, uint32_t tag,
-                                 uint32_t arg)
+/* Record that data is available for a queued command.  Returns zero if
+   the device was reselected, nonzero if the IO is deferred.  */
+static int lsi_queue_tag(LSIState *s, uint32_t tag, uint32_t len)
 {
-    LSIState *s = DO_UPCAST(LSIState, dev.qdev, bus->qbus.parent);
+    lsi_request *p;
+
+    p = lsi_find_by_tag(s, tag);
+    if (!p) {
+        BADF("IO with unknown tag %d\n", tag);
+        return 1;
+    }
+
+    if (p->pending) {
+        BADF("Multiple IO pending for tag %d\n", tag);
+    }
+    p->pending = len;
+    /* Reselect if waiting for it, or if reselection triggers an IRQ
+       and the bus is free.
+       Since no interrupt stacking is implemented in the emulation, it
+       is also required that there are no pending interrupts waiting
+       for service from the device driver. */
+    if (s->waiting == 1 ||
+        (lsi_irq_on_rsl(s) && !(s->scntl1 & LSI_SCNTL1_CON) &&
+         !(s->istat0 & (LSI_ISTAT0_SIP | LSI_ISTAT0_DIP)))) {
+        /* Reselect device.  */
+        lsi_reselect(s, p);
+        return 0;
+    } else {
+        DPRINTF("Queueing IO tag=0x%x\n", tag);
+        p->pending = len;
+        return 1;
+    }
+}
+
+ /* Callback to indicate that the SCSI layer has completed a command.  */
+static void lsi_command_complete(SCSIRequest *req, uint32_t status)
+{
+    LSIState *s = DO_UPCAST(LSIState, dev.qdev, req->bus->qbus.parent);
     int out;
 
     out = (s->sstat1 & PHASE_MASK) == PHASE_DO;
-    if (reason == SCSI_REASON_DONE) {
-        DPRINTF("Command complete status=%d\n", (int)arg);
-        s->status = arg;
-        s->command_complete = 2;
-        if (s->waiting && s->dbc != 0) {
-            /* Raise phase mismatch for short transfers.  */
-            lsi_bad_phase(s, out, PHASE_ST);
-        } else {
-            lsi_set_phase(s, PHASE_ST);
-        }
+    DPRINTF("Command complete status=%d\n", (int)status);
+    s->status = status;
+    s->command_complete = 2;
+    if (s->waiting && s->dbc != 0) {
+        /* Raise phase mismatch for short transfers.  */
+        lsi_bad_phase(s, out, PHASE_ST);
+    } else {
+        lsi_set_phase(s, PHASE_ST);
+    }
 
+    if (s->current && req == s->current->req) {
+        scsi_req_unref(s->current->req);
         qemu_free(s->current);
         s->current = NULL;
-
-        lsi_resume_script(s);
-        return;
     }
+    lsi_resume_script(s);
+}
+
+ /* Callback to indicate that the SCSI layer has completed a transfer.  */
+static void lsi_transfer_data(SCSIRequest *req, uint32_t len)
+{
+    LSIState *s = DO_UPCAST(LSIState, dev.qdev, req->bus->qbus.parent);
+    int out;
 
-    if (s->waiting == 1 || !s->current || tag != s->current->tag ||
+    if (s->waiting == 1 || !s->current || req->tag != s->current->tag ||
         (lsi_irq_on_rsl(s) && !(s->scntl1 & LSI_SCNTL1_CON))) {
-        if (lsi_queue_tag(s, tag, arg))
+        if (lsi_queue_tag(s, req->tag, len)) {
             return;
+        }
     }
 
+    out = (s->sstat1 & PHASE_MASK) == PHASE_DO;
+
     /* host adapter (re)connected */
-    DPRINTF("Data ready tag=0x%x len=%d\n", tag, arg);
-    s->current->dma_len = arg;
+    DPRINTF("Data ready tag=0x%x len=%d\n", req->tag, len);
+    s->current->dma_len = len;
     s->command_complete = 1;
-    if (!s->waiting)
-        return;
-    if (s->waiting == 1 || s->dbc == 0) {
-        lsi_resume_script(s);
-    } else {
-        lsi_do_dma(s, out);
+    if (s->waiting) {
+        if (s->waiting == 1 || s->dbc == 0) {
+            lsi_resume_script(s);
+        } else {
+            lsi_do_dma(s, out);
+        }
     }
 }
 
@@ -755,16 +789,17 @@ static void lsi_do_command(LSIState *s)
     assert(s->current == NULL);
     s->current = qemu_mallocz(sizeof(lsi_request));
     s->current->tag = s->select_tag;
+    s->current->req = scsi_req_new(dev, s->current->tag, s->current_lun);
 
-    n = dev->info->send_command(dev, s->current->tag, buf, s->current_lun);
-    if (n > 0) {
-        lsi_set_phase(s, PHASE_DI);
-        dev->info->read_data(dev, s->current->tag);
-    } else if (n < 0) {
-        lsi_set_phase(s, PHASE_DO);
-        dev->info->write_data(dev, s->current->tag);
+    n = scsi_req_enqueue(s->current->req, buf);
+    if (n) {
+        if (n > 0) {
+            lsi_set_phase(s, PHASE_DI);
+        } else if (n < 0) {
+            lsi_set_phase(s, PHASE_DO);
+        }
+        scsi_req_continue(s->current->req);
     }
-
     if (!s->command_complete) {
         if (n) {
             /* Command did not complete immediately so disconnect.  */
@@ -855,13 +890,15 @@ static void lsi_do_msgout(LSIState *s)
     int len;
     uint32_t current_tag;
     SCSIDevice *current_dev;
-    lsi_request *p, *p_next;
+    lsi_request *current_req, *p, *p_next;
     int id;
 
     if (s->current) {
         current_tag = s->current->tag;
+        current_req = s->current;
     } else {
         current_tag = s->select_tag;
+        current_req = lsi_find_by_tag(s, current_tag);
     }
     id = (current_tag >> 8) & 0xf;
     current_dev = s->bus.devs[id];
@@ -913,7 +950,9 @@ static void lsi_do_msgout(LSIState *s)
         case 0x0d:
             /* The ABORT TAG message clears the current I/O process only. */
             DPRINTF("MSG: ABORT TAG tag=0x%x\n", current_tag);
-            current_dev->info->cancel_io(current_dev, current_tag);
+            if (current_req) {
+                scsi_req_cancel(current_req->req);
+            }
             lsi_disconnect(s);
             break;
         case 0x06:
@@ -936,7 +975,9 @@ static void lsi_do_msgout(LSIState *s)
             }
 
             /* clear the current I/O process */
-            current_dev->info->cancel_io(current_dev, current_tag);
+            if (s->current) {
+                scsi_req_cancel(s->current->req);
+            }
 
             /* As the current implemented devices scsi_disk and scsi_generic
                only support one LUN, we don't need to keep track of LUNs.
@@ -948,8 +989,7 @@ static void lsi_do_msgout(LSIState *s)
             id = current_tag & 0x0000ff00;
             QTAILQ_FOREACH_SAFE(p, &s->queue, next, p_next) {
                 if ((p->tag & 0x0000ff00) == id) {
-                    current_dev->info->cancel_io(current_dev, p->tag);
-                    QTAILQ_REMOVE(&s->queue, p, next);
+                    scsi_req_cancel(p->req);
                 }
             }
 
@@ -2205,6 +2245,12 @@ static int lsi_scsi_uninit(PCIDevice *d)
     return 0;
 }
 
+static const struct SCSIBusOps lsi_scsi_ops = {
+    .transfer_data = lsi_transfer_data,
+    .complete = lsi_command_complete,
+    .cancel = lsi_request_cancelled
+};
+
 static int lsi_scsi_init(PCIDevice *dev)
 {
     LSIState *s = DO_UPCAST(LSIState, dev, dev);
@@ -2241,7 +2287,7 @@ static int lsi_scsi_init(PCIDevice *dev)
                            PCI_BASE_ADDRESS_SPACE_MEMORY, lsi_ram_mapfunc);
     QTAILQ_INIT(&s->queue);
 
-    scsi_bus_new(&s->bus, &dev->qdev, 1, LSI_MAX_DEVS, lsi_command_complete);
+    scsi_bus_new(&s->bus, &dev->qdev, 1, LSI_MAX_DEVS, &lsi_scsi_ops);
     if (!dev->qdev.hotplugged) {
         return scsi_bus_legacy_handle_cmdline(&s->bus);
     }
diff --git a/hw/pci_ids.h b/hw/pci_ids.h
index ea3418cef2..d9457ed3f4 100644
--- a/hw/pci_ids.h
+++ b/hw/pci_ids.h
@@ -100,6 +100,7 @@
 #define PCI_VENDOR_ID_INTEL              0x8086
 #define PCI_DEVICE_ID_INTEL_82441        0x1237
 #define PCI_DEVICE_ID_INTEL_82801AA_5    0x2415
+#define PCI_DEVICE_ID_INTEL_82801D       0x24CD
 #define PCI_DEVICE_ID_INTEL_ESB_9        0x25ab
 #define PCI_DEVICE_ID_INTEL_82371SB_0    0x7000
 #define PCI_DEVICE_ID_INTEL_82371SB_1    0x7010
diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
index ceeb4ecb91..837f24e212 100644
--- a/hw/scsi-bus.c
+++ b/hw/scsi-bus.c
@@ -4,6 +4,7 @@
 #include "scsi-defs.h"
 #include "qdev.h"
 #include "blockdev.h"
+#include "trace.h"
 
 static char *scsibus_get_fw_dev_path(DeviceState *dev);
 
@@ -20,13 +21,13 @@ static int next_scsi_bus;
 
 /* Create a scsi bus, and attach devices to it.  */
 void scsi_bus_new(SCSIBus *bus, DeviceState *host, int tcq, int ndev,
-                  scsi_completionfn complete)
+                  const SCSIBusOps *ops)
 {
     qbus_create_inplace(&bus->qbus, &scsi_bus_info, host, NULL);
     bus->busnr = next_scsi_bus++;
     bus->tcq = tcq;
     bus->ndev = ndev;
-    bus->complete = complete;
+    bus->ops = ops;
     bus->qbus.allow_hotplug = 1;
 }
 
@@ -135,42 +136,60 @@ SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag, uint32_t l
     SCSIRequest *req;
 
     req = qemu_mallocz(size);
+    req->refcount = 1;
     req->bus = scsi_bus_from_device(d);
     req->dev = d;
     req->tag = tag;
     req->lun = lun;
     req->status = -1;
-    req->enqueued = true;
-    QTAILQ_INSERT_TAIL(&d->requests, req, next);
+    trace_scsi_req_alloc(req->dev->id, req->lun, req->tag);
     return req;
 }
 
-SCSIRequest *scsi_req_find(SCSIDevice *d, uint32_t tag)
+SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun)
 {
-    SCSIRequest *req;
+    return d->info->alloc_req(d, tag, lun);
+}
 
-    QTAILQ_FOREACH(req, &d->requests, next) {
-        if (req->tag == tag) {
-            return req;
-        }
+uint8_t *scsi_req_get_buf(SCSIRequest *req)
+{
+    return req->dev->info->get_buf(req);
+}
+
+int scsi_req_get_sense(SCSIRequest *req, uint8_t *buf, int len)
+{
+    if (req->dev->info->get_sense) {
+        return req->dev->info->get_sense(req, buf, len);
+    } else {
+        return 0;
     }
-    return NULL;
+}
+
+int32_t scsi_req_enqueue(SCSIRequest *req, uint8_t *buf)
+{
+    int32_t rc;
+
+    assert(!req->enqueued);
+    scsi_req_ref(req);
+    req->enqueued = true;
+    QTAILQ_INSERT_TAIL(&req->dev->requests, req, next);
+
+    scsi_req_ref(req);
+    rc = req->dev->info->send_command(req, buf);
+    scsi_req_unref(req);
+    return rc;
 }
 
 static void scsi_req_dequeue(SCSIRequest *req)
 {
+    trace_scsi_req_dequeue(req->dev->id, req->lun, req->tag);
     if (req->enqueued) {
         QTAILQ_REMOVE(&req->dev->requests, req, next);
         req->enqueued = false;
+        scsi_req_unref(req);
     }
 }
 
-void scsi_req_free(SCSIRequest *req)
-{
-    scsi_req_dequeue(req);
-    qemu_free(req);
-}
-
 static int scsi_req_length(SCSIRequest *req, uint8_t *cmd)
 {
     switch (cmd[0] >> 5) {
@@ -195,6 +214,7 @@ static int scsi_req_length(SCSIRequest *req, uint8_t *cmd)
         req->cmd.len = 12;
         break;
     default:
+        trace_scsi_req_parse_bad(req->dev->id, req->lun, req->tag, cmd[0]);
         return -1;
     }
 
@@ -392,9 +412,100 @@ int scsi_req_parse(SCSIRequest *req, uint8_t *buf)
     memcpy(req->cmd.buf, buf, req->cmd.len);
     scsi_req_xfer_mode(req);
     req->cmd.lba = scsi_req_lba(req);
+    trace_scsi_req_parsed(req->dev->id, req->lun, req->tag, buf[0],
+                          req->cmd.mode, req->cmd.xfer, req->cmd.lba);
     return 0;
 }
 
+/*
+ * Predefined sense codes
+ */
+
+/* No sense data available */
+const struct SCSISense sense_code_NO_SENSE = {
+    .key = NO_SENSE , .asc = 0x00 , .ascq = 0x00
+};
+
+/* LUN not ready, Manual intervention required */
+const struct SCSISense sense_code_LUN_NOT_READY = {
+    .key = NOT_READY, .asc = 0x04, .ascq = 0x03
+};
+
+/* LUN not ready, Medium not present */
+const struct SCSISense sense_code_NO_MEDIUM = {
+    .key = NOT_READY, .asc = 0x3a, .ascq = 0x00
+};
+
+/* Hardware error, internal target failure */
+const struct SCSISense sense_code_TARGET_FAILURE = {
+    .key = HARDWARE_ERROR, .asc = 0x44, .ascq = 0x00
+};
+
+/* Illegal request, invalid command operation code */
+const struct SCSISense sense_code_INVALID_OPCODE = {
+    .key = ILLEGAL_REQUEST, .asc = 0x20, .ascq = 0x00
+};
+
+/* Illegal request, LBA out of range */
+const struct SCSISense sense_code_LBA_OUT_OF_RANGE = {
+    .key = ILLEGAL_REQUEST, .asc = 0x21, .ascq = 0x00
+};
+
+/* Illegal request, Invalid field in CDB */
+const struct SCSISense sense_code_INVALID_FIELD = {
+    .key = ILLEGAL_REQUEST, .asc = 0x24, .ascq = 0x00
+};
+
+/* Illegal request, LUN not supported */
+const struct SCSISense sense_code_LUN_NOT_SUPPORTED = {
+    .key = ILLEGAL_REQUEST, .asc = 0x25, .ascq = 0x00
+};
+
+/* Command aborted, I/O process terminated */
+const struct SCSISense sense_code_IO_ERROR = {
+    .key = ABORTED_COMMAND, .asc = 0x00, .ascq = 0x06
+};
+
+/* Command aborted, I_T Nexus loss occurred */
+const struct SCSISense sense_code_I_T_NEXUS_LOSS = {
+    .key = ABORTED_COMMAND, .asc = 0x29, .ascq = 0x07
+};
+
+/* Command aborted, Logical Unit failure */
+const struct SCSISense sense_code_LUN_FAILURE = {
+    .key = ABORTED_COMMAND, .asc = 0x3e, .ascq = 0x01
+};
+
+/*
+ * scsi_build_sense
+ *
+ * Build a sense buffer
+ */
+int scsi_build_sense(SCSISense sense, uint8_t *buf, int len, int fixed)
+{
+    if (!fixed && len < 8) {
+        return 0;
+    }
+
+    memset(buf, 0, len);
+    if (fixed) {
+        /* Return fixed format sense buffer */
+        buf[0] = 0xf0;
+        buf[2] = sense.key;
+        buf[7] = 7;
+        buf[12] = sense.asc;
+        buf[13] = sense.ascq;
+        return MIN(len, 18);
+    } else {
+        /* Return descriptor format sense buffer */
+        buf[0] = 0x72;
+        buf[1] = sense.key;
+        buf[2] = sense.asc;
+        buf[3] = sense.ascq;
+        return 8;
+    }
+}
+
 static const char *scsi_command_name(uint8_t cmd)
 {
     static const char *names[] = {
@@ -489,6 +600,43 @@ static const char *scsi_command_name(uint8_t cmd)
     return names[cmd];
 }
 
+SCSIRequest *scsi_req_ref(SCSIRequest *req)
+{
+    req->refcount++;
+    return req;
+}
+
+void scsi_req_unref(SCSIRequest *req)
+{
+    if (--req->refcount == 0) {
+        if (req->dev->info->free_req) {
+            req->dev->info->free_req(req);
+        }
+        qemu_free(req);
+    }
+}
+
+/* Tell the device that we finished processing this chunk of I/O.  It
+   will start the next chunk or complete the command.  */
+void scsi_req_continue(SCSIRequest *req)
+{
+    trace_scsi_req_continue(req->dev->id, req->lun, req->tag);
+    if (req->cmd.mode == SCSI_XFER_TO_DEV) {
+        req->dev->info->write_data(req);
+    } else {
+        req->dev->info->read_data(req);
+    }
+}
+
+/* Called by the devices when data is ready for the HBA.  The HBA should
+   start a DMA operation to read or fill the device's data buffer.
+   Once it completes, calling scsi_req_continue will restart I/O.  */
+void scsi_req_data(SCSIRequest *req, int len)
+{
+    trace_scsi_req_data(req->dev->id, req->lun, req->tag, len);
+    req->bus->ops->transfer_data(req, len);
+}
+
 void scsi_req_print(SCSIRequest *req)
 {
     FILE *fp = stderr;
@@ -520,10 +668,42 @@ void scsi_req_print(SCSIRequest *req)
 void scsi_req_complete(SCSIRequest *req)
 {
     assert(req->status != -1);
+    scsi_req_ref(req);
+    scsi_req_dequeue(req);
+    req->bus->ops->complete(req, req->status);
+    scsi_req_unref(req);
+}
+
+void scsi_req_cancel(SCSIRequest *req)
+{
+    if (req->dev && req->dev->info->cancel_io) {
+        req->dev->info->cancel_io(req);
+    }
+    scsi_req_ref(req);
     scsi_req_dequeue(req);
-    req->bus->complete(req->bus, SCSI_REASON_DONE,
-                       req->tag,
-                       req->status);
+    if (req->bus->ops->cancel) {
+        req->bus->ops->cancel(req);
+    }
+    scsi_req_unref(req);
+}
+
+void scsi_req_abort(SCSIRequest *req, int status)
+{
+    req->status = status;
+    if (req->dev && req->dev->info->cancel_io) {
+        req->dev->info->cancel_io(req);
+    }
+    scsi_req_complete(req);
+}
+
+void scsi_device_purge_requests(SCSIDevice *sdev)
+{
+    SCSIRequest *req;
+
+    while (!QTAILQ_EMPTY(&sdev->requests)) {
+        req = QTAILQ_FIRST(&sdev->requests);
+        scsi_req_cancel(req);
+    }
 }
 
 static char *scsibus_get_fw_dev_path(DeviceState *dev)
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 397b9d6b39..a8c7372d3e 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -49,14 +49,8 @@ do { fprintf(stderr, "scsi-disk: " fmt , ## __VA_ARGS__); } while (0)
 
 typedef struct SCSIDiskState SCSIDiskState;
 
-typedef struct SCSISense {
-    uint8_t key;
-} SCSISense;
-
 typedef struct SCSIDiskReq {
     SCSIRequest req;
-    /* ??? We should probably keep track of whether the data transfer is
-       a read or a write.  Currently we rely on the host getting it right.  */
     /* Both sector and sector_count are in terms of qemu 512 byte blocks.  */
     uint64_t sector;
     uint32_t sector_count;
@@ -86,27 +80,24 @@ struct SCSIDiskState
 static int scsi_handle_rw_error(SCSIDiskReq *r, int error, int type);
 static int scsi_disk_emulate_command(SCSIDiskReq *r, uint8_t *outbuf);
 
-static SCSIDiskReq *scsi_new_request(SCSIDiskState *s, uint32_t tag,
+static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag,
         uint32_t lun)
 {
+    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
     SCSIRequest *req;
     SCSIDiskReq *r;
 
     req = scsi_req_alloc(sizeof(SCSIDiskReq), &s->qdev, tag, lun);
     r = DO_UPCAST(SCSIDiskReq, req, req);
     r->iov.iov_base = qemu_blockalign(s->bs, SCSI_DMA_BUF_SIZE);
-    return r;
+    return req;
 }
 
-static void scsi_remove_request(SCSIDiskReq *r)
+static void scsi_free_request(SCSIRequest *req)
 {
-    qemu_vfree(r->iov.iov_base);
-    scsi_req_free(&r->req);
-}
+    SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req);
 
-static SCSIDiskReq *scsi_find_request(SCSIDiskState *s, uint32_t tag)
-{
-    return DO_UPCAST(SCSIDiskReq, req, scsi_req_find(&s->qdev, tag));
+    qemu_vfree(r->iov.iov_base);
 }
 
 static void scsi_disk_clear_sense(SCSIDiskState *s)
@@ -114,42 +105,33 @@ static void scsi_disk_clear_sense(SCSIDiskState *s)
     memset(&s->sense, 0, sizeof(s->sense));
 }
 
-static void scsi_disk_set_sense(SCSIDiskState *s, uint8_t key)
-{
-    s->sense.key = key;
-}
-
-static void scsi_req_set_status(SCSIDiskReq *r, int status, int sense_code)
+static void scsi_req_set_status(SCSIDiskReq *r, int status, SCSISense sense)
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
 
     r->req.status = status;
-    scsi_disk_set_sense(s, sense_code);
+    s->sense = sense;
 }
 
 /* Helper function for command completion.  */
-static void scsi_command_complete(SCSIDiskReq *r, int status, int sense)
+static void scsi_command_complete(SCSIDiskReq *r, int status, SCSISense sense)
 {
-    DPRINTF("Command complete tag=0x%x status=%d sense=%d\n",
-            r->req.tag, status, sense);
+    DPRINTF("Command complete tag=0x%x status=%d sense=%d/%d/%d\n",
+            r->req.tag, status, sense.key, sense.asc, sense.ascq);
     scsi_req_set_status(r, status, sense);
     scsi_req_complete(&r->req);
-    scsi_remove_request(r);
 }
 
 /* Cancel a pending data transfer.  */
-static void scsi_cancel_io(SCSIDevice *d, uint32_t tag)
+static void scsi_cancel_io(SCSIRequest *req)
 {
-    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
-    SCSIDiskReq *r;
-    DPRINTF("Cancel tag=0x%x\n", tag);
-    r = scsi_find_request(s, tag);
-    if (r) {
-        if (r->req.aiocb)
-            bdrv_aio_cancel(r->req.aiocb);
-        r->req.aiocb = NULL;
-        scsi_remove_request(r);
+    SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req);
+
+    DPRINTF("Cancel tag=0x%x\n", req->tag);
+    if (r->req.aiocb) {
+        bdrv_aio_cancel(r->req.aiocb);
     }
+    r->req.aiocb = NULL;
 }
 
 static void scsi_read_complete(void * opaque, int ret)
@@ -170,30 +152,38 @@ static void scsi_read_complete(void * opaque, int ret)
     n = r->iov.iov_len / 512;
     r->sector += n;
     r->sector_count -= n;
-    r->req.bus->complete(r->req.bus, SCSI_REASON_DATA, r->req.tag, r->iov.iov_len);
+    scsi_req_data(&r->req, r->iov.iov_len);
 }
 
 
-static void scsi_read_request(SCSIDiskReq *r)
+/* Read more data from scsi device into buffer.  */
+static void scsi_read_data(SCSIRequest *req)
 {
+    SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req);
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
     uint32_t n;
 
     if (r->sector_count == (uint32_t)-1) {
         DPRINTF("Read buf_len=%zd\n", r->iov.iov_len);
         r->sector_count = 0;
-        r->req.bus->complete(r->req.bus, SCSI_REASON_DATA, r->req.tag, r->iov.iov_len);
+        scsi_req_data(&r->req, r->iov.iov_len);
         return;
     }
     DPRINTF("Read sector_count=%d\n", r->sector_count);
     if (r->sector_count == 0) {
-        scsi_command_complete(r, GOOD, NO_SENSE);
+        scsi_command_complete(r, GOOD, SENSE_CODE(NO_SENSE));
         return;
     }
 
     /* No data transfer may already be in progress */
     assert(r->req.aiocb == NULL);
 
+    if (r->req.cmd.mode == SCSI_XFER_TO_DEV) {
+        DPRINTF("Data transfer direction invalid\n");
+        scsi_read_complete(r, -EINVAL);
+        return;
+    }
+
     n = r->sector_count;
     if (n > SCSI_DMA_BUF_SIZE / 512)
         n = SCSI_DMA_BUF_SIZE / 512;
@@ -207,23 +197,6 @@ static void scsi_read_request(SCSIDiskReq *r)
     }
 }
 
-/* Read more data from scsi device into buffer.  */
-static void scsi_read_data(SCSIDevice *d, uint32_t tag)
-{
-    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
-    SCSIDiskReq *r;
-
-    r = scsi_find_request(s, tag);
-    if (!r) {
-        BADF("Bad read tag 0x%x\n", tag);
-        /* ??? This is the wrong error.  */
-        scsi_command_complete(r, CHECK_CONDITION, HARDWARE_ERROR);
-        return;
-    }
-
-    scsi_read_request(r);
-}
-
 static int scsi_handle_rw_error(SCSIDiskReq *r, int error, int type)
 {
     int is_read = (type == SCSI_REQ_STATUS_RETRY_READ);
@@ -245,13 +218,24 @@ static int scsi_handle_rw_error(SCSIDiskReq *r, int error, int type)
         vm_stop(VMSTOP_DISKFULL);
     } else {
         if (type == SCSI_REQ_STATUS_RETRY_READ) {
-            r->req.bus->complete(r->req.bus, SCSI_REASON_DATA, r->req.tag, 0);
+            scsi_req_data(&r->req, 0);
+        }
+        switch (error) {
+        case ENOMEM:
+            scsi_command_complete(r, CHECK_CONDITION,
+                                  SENSE_CODE(TARGET_FAILURE));
+            break;
+        case EINVAL:
+            scsi_command_complete(r, CHECK_CONDITION,
+                                  SENSE_CODE(INVALID_FIELD));
+            break;
+        default:
+            scsi_command_complete(r, CHECK_CONDITION,
+                                  SENSE_CODE(IO_ERROR));
+            break;
         }
-        scsi_command_complete(r, CHECK_CONDITION,
-                HARDWARE_ERROR);
         bdrv_mon_event(s->bs, BDRV_ACTION_REPORT, is_read);
     }
-
     return 1;
 }
 
@@ -273,7 +257,7 @@ static void scsi_write_complete(void * opaque, int ret)
     r->sector += n;
     r->sector_count -= n;
     if (r->sector_count == 0) {
-        scsi_command_complete(r, GOOD, NO_SENSE);
+        scsi_command_complete(r, GOOD, SENSE_CODE(NO_SENSE));
     } else {
         len = r->sector_count * 512;
         if (len > SCSI_DMA_BUF_SIZE) {
@@ -281,25 +265,32 @@ static void scsi_write_complete(void * opaque, int ret)
         }
         r->iov.iov_len = len;
         DPRINTF("Write complete tag=0x%x more=%d\n", r->req.tag, len);
-        r->req.bus->complete(r->req.bus, SCSI_REASON_DATA, r->req.tag, len);
+        scsi_req_data(&r->req, len);
     }
 }
 
-static void scsi_write_request(SCSIDiskReq *r)
+static void scsi_write_data(SCSIRequest *req)
 {
+    SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req);
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
     uint32_t n;
 
     /* No data transfer may already be in progress */
     assert(r->req.aiocb == NULL);
 
+    if (r->req.cmd.mode != SCSI_XFER_TO_DEV) {
+        DPRINTF("Data transfer direction invalid\n");
+        scsi_write_complete(r, -EINVAL);
+        return;
+    }
+
     n = r->iov.iov_len / 512;
     if (n) {
         qemu_iovec_init_external(&r->qiov, &r->iov, 1);
         r->req.aiocb = bdrv_aio_writev(s->bs, r->sector, &r->qiov, n,
                                    scsi_write_complete, r);
         if (r->req.aiocb == NULL) {
-            scsi_write_complete(r, -EIO);
+            scsi_write_complete(r, -ENOMEM);
         }
     } else {
         /* Invoke completion routine to fetch data from host.  */
@@ -307,26 +298,6 @@ static void scsi_write_request(SCSIDiskReq *r)
     }
 }
 
-/* Write data to a scsi device.  Returns nonzero on failure.
-   The transfer may complete asynchronously.  */
-static int scsi_write_data(SCSIDevice *d, uint32_t tag)
-{
-    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
-    SCSIDiskReq *r;
-
-    DPRINTF("Write data tag=0x%x\n", tag);
-    r = scsi_find_request(s, tag);
-    if (!r) {
-        BADF("Bad write tag 0x%x\n", tag);
-        scsi_command_complete(r, CHECK_CONDITION, HARDWARE_ERROR);
-        return 1;
-    }
-
-    scsi_write_request(r);
-
-    return 0;
-}
-
 static void scsi_dma_restart_bh(void *opaque)
 {
     SCSIDiskState *s = opaque;
@@ -347,15 +318,15 @@ static void scsi_dma_restart_bh(void *opaque)
 
             switch (status & SCSI_REQ_STATUS_RETRY_TYPE_MASK) {
             case SCSI_REQ_STATUS_RETRY_READ:
-                scsi_read_request(r);
+                scsi_read_data(&r->req);
                 break;
             case SCSI_REQ_STATUS_RETRY_WRITE:
-                scsi_write_request(r);
+                scsi_write_data(&r->req);
                 break;
             case SCSI_REQ_STATUS_RETRY_FLUSH:
                 ret = scsi_disk_emulate_command(r, r->iov.iov_base);
                 if (ret == 0) {
-                    scsi_command_complete(r, GOOD, NO_SENSE);
+                    scsi_command_complete(r, GOOD, SENSE_CODE(NO_SENSE));
                 }
             }
         }
@@ -376,19 +347,21 @@ static void scsi_dma_restart_cb(void *opaque, int running, int reason)
 }
 
 /* Return a pointer to the data buffer.  */
-static uint8_t *scsi_get_buf(SCSIDevice *d, uint32_t tag)
+static uint8_t *scsi_get_buf(SCSIRequest *req)
 {
-    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
-    SCSIDiskReq *r;
+    SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req);
 
-    r = scsi_find_request(s, tag);
-    if (!r) {
-        BADF("Bad buffer tag 0x%x\n", tag);
-        return NULL;
-    }
     return (uint8_t *)r->iov.iov_base;
 }
 
+/* Copy sense information into the provided buffer */
+static int scsi_get_sense(SCSIRequest *req, uint8_t *outbuf, int len)
+{
+    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
+
+    return scsi_build_sense(s->sense, outbuf, len, len > 14);
+}
+
 static int scsi_disk_emulate_inquiry(SCSIRequest *req, uint8_t *outbuf)
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
@@ -545,7 +518,7 @@ static int scsi_disk_emulate_inquiry(SCSIRequest *req, uint8_t *outbuf)
 
     memset(outbuf, 0, buflen);
 
-    if (req->lun || req->cmd.buf[1] >> 5) {
+    if (req->lun) {
         outbuf[0] = 0x7f;	/* LUN not supported */
         return buflen;
     }
@@ -860,19 +833,8 @@ static int scsi_disk_emulate_command(SCSIDiskReq *r, uint8_t *outbuf)
     case REQUEST_SENSE:
         if (req->cmd.xfer < 4)
             goto illegal_request;
-        memset(outbuf, 0, 4);
-        buflen = 4;
-        if (s->sense.key == NOT_READY && req->cmd.xfer >= 18) {
-            memset(outbuf, 0, 18);
-            buflen = 18;
-            outbuf[7] = 10;
-            /* asc 0x3a, ascq 0: Medium not present */
-            outbuf[12] = 0x3a;
-            outbuf[13] = 0;
-        }
-        outbuf[0] = 0xf0;
-        outbuf[1] = 0;
-        outbuf[2] = s->sense.key;
+        buflen = scsi_build_sense(s->sense, outbuf, req->cmd.xfer,
+                                  req->cmd.xfer > 13);
         scsi_disk_clear_sense(s);
         break;
     case INQUIRY:
@@ -1010,17 +972,22 @@ static int scsi_disk_emulate_command(SCSIDiskReq *r, uint8_t *outbuf)
         }
         break;
     default:
-        goto illegal_request;
+        scsi_command_complete(r, CHECK_CONDITION, SENSE_CODE(INVALID_OPCODE));
+        return -1;
     }
-    scsi_req_set_status(r, GOOD, NO_SENSE);
+    scsi_req_set_status(r, GOOD, SENSE_CODE(NO_SENSE));
     return buflen;
 
 not_ready:
-    scsi_command_complete(r, CHECK_CONDITION, NOT_READY);
+    if (!bdrv_is_inserted(s->bs)) {
+        scsi_command_complete(r, CHECK_CONDITION, SENSE_CODE(NO_MEDIUM));
+    } else {
+        scsi_command_complete(r, CHECK_CONDITION, SENSE_CODE(LUN_NOT_READY));
+    }
     return -1;
 
 illegal_request:
-    scsi_command_complete(r, CHECK_CONDITION, ILLEGAL_REQUEST);
+    scsi_command_complete(r, CHECK_CONDITION, SENSE_CODE(INVALID_FIELD));
     return -1;
 }
 
@@ -1029,33 +996,23 @@ illegal_request:
    (eg. disk reads), negative for transfers to the device (eg. disk writes),
    and zero if the command does not transfer any data.  */
 
-static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
-                                 uint8_t *buf, int lun)
+static int32_t scsi_send_command(SCSIRequest *req, uint8_t *buf)
 {
-    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
-    uint32_t len;
-    int is_write;
+    SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req);
+    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
+    int32_t len;
     uint8_t command;
     uint8_t *outbuf;
-    SCSIDiskReq *r;
     int rc;
 
     command = buf[0];
-    r = scsi_find_request(s, tag);
-    if (r) {
-        BADF("Tag 0x%x already in use\n", tag);
-        scsi_cancel_io(d, tag);
-    }
-    /* ??? Tags are not unique for different luns.  We only implement a
-       single lun, so this should not matter.  */
-    r = scsi_new_request(s, tag, lun);
     outbuf = (uint8_t *)r->iov.iov_base;
-    is_write = 0;
     DPRINTF("Command: lun=%d tag=0x%x data=0x%02x", lun, tag, buf[0]);
 
     if (scsi_req_parse(&r->req, buf) != 0) {
         BADF("Unsupported command length, command %x\n", command);
-        goto fail;
+        scsi_command_complete(r, CHECK_CONDITION, SENSE_CODE(INVALID_OPCODE));
+        return 0;
     }
 #ifdef DEBUG_SCSI
     {
@@ -1067,11 +1024,14 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
     }
 #endif
 
-    if (lun || buf[1] >> 5) {
+    if (req->lun) {
         /* Only LUN 0 supported.  */
-        DPRINTF("Unimplemented LUN %d\n", lun ? lun : buf[1] >> 5);
-        if (command != REQUEST_SENSE && command != INQUIRY)
-            goto fail;
+        DPRINTF("Unimplemented LUN %d\n", req->lun);
+        if (command != REQUEST_SENSE && command != INQUIRY) {
+            scsi_command_complete(r, CHECK_CONDITION,
+                                  SENSE_CODE(LUN_NOT_SUPPORTED));
+            return 0;
+        }
     }
     switch (command) {
     case TEST_UNIT_READY:
@@ -1104,7 +1064,7 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
     case READ_10:
     case READ_12:
     case READ_16:
-        len = r->req.cmd.xfer / d->blocksize;
+        len = r->req.cmd.xfer / s->qdev.blocksize;
         DPRINTF("Read (sector %" PRId64 ", count %d)\n", r->req.cmd.lba, len);
         if (r->req.cmd.lba > s->max_lba)
             goto illegal_lba;
@@ -1118,7 +1078,7 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
     case WRITE_VERIFY:
     case WRITE_VERIFY_12:
     case WRITE_VERIFY_16:
-        len = r->req.cmd.xfer / d->blocksize;
+        len = r->req.cmd.xfer / s->qdev.blocksize;
         DPRINTF("Write %s(sector %" PRId64 ", count %d)\n",
                 (command & 0xe) == 0xe ? "And Verify " : "",
                 r->req.cmd.lba, len);
@@ -1126,7 +1086,6 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
             goto illegal_lba;
         r->sector = r->req.cmd.lba * s->cluster_size;
         r->sector_count = len * s->cluster_size;
-        is_write = 1;
         break;
     case MODE_SELECT:
         DPRINTF("Mode Select(6) (len %lu)\n", (long)r->req.cmd.xfer);
@@ -1153,7 +1112,7 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
         }
         break;
     case WRITE_SAME_16:
-        len = r->req.cmd.xfer / d->blocksize;
+        len = r->req.cmd.xfer / s->qdev.blocksize;
 
         DPRINTF("WRITE SAME(16) (sector %" PRId64 ", count %d)\n",
                 r->req.cmd.lba, len);
@@ -1179,18 +1138,20 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
         break;
     default:
         DPRINTF("Unknown SCSI command (%2.2x)\n", buf[0]);
+        scsi_command_complete(r, CHECK_CONDITION, SENSE_CODE(INVALID_OPCODE));
+        return 0;
     fail:
-        scsi_command_complete(r, CHECK_CONDITION, ILLEGAL_REQUEST);
+        scsi_command_complete(r, CHECK_CONDITION, SENSE_CODE(INVALID_FIELD));
         return 0;
     illegal_lba:
-        scsi_command_complete(r, CHECK_CONDITION, HARDWARE_ERROR);
+        scsi_command_complete(r, CHECK_CONDITION, SENSE_CODE(LBA_OUT_OF_RANGE));
         return 0;
     }
     if (r->sector_count == 0 && r->iov.iov_len == 0) {
-        scsi_command_complete(r, GOOD, NO_SENSE);
+        scsi_command_complete(r, GOOD, SENSE_CODE(NO_SENSE));
     }
     len = r->sector_count * 512 + r->iov.iov_len;
-    if (is_write) {
+    if (r->req.cmd.mode == SCSI_XFER_TO_DEV) {
         return -len;
     } else {
         if (!r->sector_count)
@@ -1199,25 +1160,12 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
     }
 }
 
-static void scsi_disk_purge_requests(SCSIDiskState *s)
-{
-    SCSIDiskReq *r;
-
-    while (!QTAILQ_EMPTY(&s->qdev.requests)) {
-        r = DO_UPCAST(SCSIDiskReq, req, QTAILQ_FIRST(&s->qdev.requests));
-        if (r->req.aiocb) {
-            bdrv_aio_cancel(r->req.aiocb);
-        }
-        scsi_remove_request(r);
-    }
-}
-
 static void scsi_disk_reset(DeviceState *dev)
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev.qdev, dev);
     uint64_t nb_sectors;
 
-    scsi_disk_purge_requests(s);
+    scsi_device_purge_requests(&s->qdev);
 
     bdrv_get_geometry(s->bs, &nb_sectors);
     nb_sectors /= s->cluster_size;
@@ -1231,7 +1179,7 @@ static void scsi_destroy(SCSIDevice *dev)
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, dev);
 
-    scsi_disk_purge_requests(s);
+    scsi_device_purge_requests(&s->qdev);
     blockdev_mark_auto_del(s->qdev.conf.bs);
 }
 
@@ -1321,11 +1269,14 @@ static SCSIDeviceInfo scsi_disk_info[] = {
         .qdev.reset   = scsi_disk_reset,
         .init         = scsi_hd_initfn,
         .destroy      = scsi_destroy,
+        .alloc_req    = scsi_new_request,
+        .free_req     = scsi_free_request,
         .send_command = scsi_send_command,
         .read_data    = scsi_read_data,
         .write_data   = scsi_write_data,
         .cancel_io    = scsi_cancel_io,
         .get_buf      = scsi_get_buf,
+        .get_sense    = scsi_get_sense,
         .qdev.props   = (Property[]) {
             DEFINE_SCSI_DISK_PROPERTIES(),
             DEFINE_PROP_BIT("removable", SCSIDiskState, removable, 0, false),
@@ -1339,11 +1290,14 @@ static SCSIDeviceInfo scsi_disk_info[] = {
         .qdev.reset   = scsi_disk_reset,
         .init         = scsi_cd_initfn,
         .destroy      = scsi_destroy,
+        .alloc_req    = scsi_new_request,
+        .free_req     = scsi_free_request,
         .send_command = scsi_send_command,
         .read_data    = scsi_read_data,
         .write_data   = scsi_write_data,
         .cancel_io    = scsi_cancel_io,
         .get_buf      = scsi_get_buf,
+        .get_sense    = scsi_get_sense,
         .qdev.props   = (Property[]) {
             DEFINE_SCSI_DISK_PROPERTIES(),
             DEFINE_PROP_END_OF_LIST(),
@@ -1356,11 +1310,14 @@ static SCSIDeviceInfo scsi_disk_info[] = {
         .qdev.reset   = scsi_disk_reset,
         .init         = scsi_disk_initfn,
         .destroy      = scsi_destroy,
+        .alloc_req    = scsi_new_request,
+        .free_req     = scsi_free_request,
         .send_command = scsi_send_command,
         .read_data    = scsi_read_data,
         .write_data   = scsi_write_data,
         .cancel_io    = scsi_cancel_io,
         .get_buf      = scsi_get_buf,
+        .get_sense    = scsi_get_sense,
         .qdev.props   = (Property[]) {
             DEFINE_SCSI_DISK_PROPERTIES(),
             DEFINE_PROP_BIT("removable", SCSIDiskState, removable, 0, false),
diff --git a/hw/scsi-generic.c b/hw/scsi-generic.c
index 9be1cca4c3..8e59c7ee89 100644
--- a/hw/scsi-generic.c
+++ b/hw/scsi-generic.c
@@ -66,23 +66,49 @@ struct SCSIGenericState
     uint8_t senselen;
 };
 
-static SCSIGenericReq *scsi_new_request(SCSIDevice *d, uint32_t tag, uint32_t lun)
+static void scsi_set_sense(SCSIGenericState *s, SCSISense sense)
 {
-    SCSIRequest *req;
+    s->senselen = scsi_build_sense(sense, s->sensebuf, SCSI_SENSE_BUF_SIZE, 0);
+    s->driver_status = SG_ERR_DRIVER_SENSE;
+}
 
-    req = scsi_req_alloc(sizeof(SCSIGenericReq), d, tag, lun);
-    return DO_UPCAST(SCSIGenericReq, req, req);
+static void scsi_clear_sense(SCSIGenericState *s)
+{
+    memset(s->sensebuf, 0, SCSI_SENSE_BUF_SIZE);
+    s->senselen = 0;
+    s->driver_status = 0;
 }
 
-static void scsi_remove_request(SCSIGenericReq *r)
+static int scsi_get_sense(SCSIRequest *req, uint8_t *outbuf, int len)
 {
-    qemu_free(r->buf);
-    scsi_req_free(&r->req);
+    SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, req->dev);
+    int size = SCSI_SENSE_BUF_SIZE;
+
+    if (!(s->driver_status & SG_ERR_DRIVER_SENSE)) {
+        size = scsi_build_sense(SENSE_CODE(NO_SENSE), s->sensebuf,
+                                SCSI_SENSE_BUF_SIZE, 0);
+    }
+    if (size > len) {
+        size = len;
+    }
+    memcpy(outbuf, s->sensebuf, size);
+
+    return size;
 }
 
-static SCSIGenericReq *scsi_find_request(SCSIGenericState *s, uint32_t tag)
+static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag, uint32_t lun)
 {
-    return DO_UPCAST(SCSIGenericReq, req, scsi_req_find(&s->qdev, tag));
+    SCSIRequest *req;
+
+    req = scsi_req_alloc(sizeof(SCSIGenericReq), d, tag, lun);
+    return req;
+}
+
+static void scsi_free_request(SCSIRequest *req)
+{
+    SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
+
+    qemu_free(r->buf);
 }
 
 /* Helper function for command completion.  */
@@ -91,13 +117,30 @@ static void scsi_command_complete(void *opaque, int ret)
     SCSIGenericReq *r = (SCSIGenericReq *)opaque;
     SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, r->req.dev);
 
+    r->req.aiocb = NULL;
     s->driver_status = r->io_header.driver_status;
     if (s->driver_status & SG_ERR_DRIVER_SENSE)
         s->senselen = r->io_header.sb_len_wr;
 
-    if (ret != 0)
-        r->req.status = BUSY;
-    else {
+    if (ret != 0) {
+        switch (ret) {
+        case -EDOM:
+            r->req.status = TASK_SET_FULL;
+            break;
+        case -EINVAL:
+            r->req.status = CHECK_CONDITION;
+            scsi_set_sense(s, SENSE_CODE(INVALID_FIELD));
+            break;
+        case -ENOMEM:
+            r->req.status = CHECK_CONDITION;
+            scsi_set_sense(s, SENSE_CODE(TARGET_FAILURE));
+            break;
+        default:
+            r->req.status = CHECK_CONDITION;
+            scsi_set_sense(s, SENSE_CODE(IO_ERROR));
+            break;
+        }
+    } else {
         if (s->driver_status & SG_ERR_DRIVER_TIMEOUT) {
             r->req.status = BUSY;
             BADF("Driver Timeout\n");
@@ -112,23 +155,18 @@ static void scsi_command_complete(void *opaque, int ret)
             r, r->req.tag, r->req.status);
 
     scsi_req_complete(&r->req);
-    scsi_remove_request(r);
 }
 
 /* Cancel a pending data transfer.  */
-static void scsi_cancel_io(SCSIDevice *d, uint32_t tag)
+static void scsi_cancel_io(SCSIRequest *req)
 {
-    DPRINTF("scsi_cancel_io 0x%x\n", tag);
-    SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, d);
-    SCSIGenericReq *r;
-    DPRINTF("Cancel tag=0x%x\n", tag);
-    r = scsi_find_request(s, tag);
-    if (r) {
-        if (r->req.aiocb)
-            bdrv_aio_cancel(r->req.aiocb);
-        r->req.aiocb = NULL;
-        scsi_remove_request(r);
+    SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
+
+    DPRINTF("Cancel tag=0x%x\n", req->tag);
+    if (r->req.aiocb) {
+        bdrv_aio_cancel(r->req.aiocb);
     }
+    r->req.aiocb = NULL;
 }
 
 static int execute_command(BlockDriverState *bdrv,
@@ -152,7 +190,7 @@ static int execute_command(BlockDriverState *bdrv,
     r->req.aiocb = bdrv_aio_ioctl(bdrv, SG_IO, &r->io_header, complete, r);
     if (r->req.aiocb == NULL) {
         BADF("execute_command: read failed !\n");
-        return -1;
+        return -ENOMEM;
     }
 
     return 0;
@@ -163,6 +201,7 @@ static void scsi_read_complete(void * opaque, int ret)
     SCSIGenericReq *r = (SCSIGenericReq *)opaque;
     int len;
 
+    r->req.aiocb = NULL;
     if (ret) {
         DPRINTF("IO error ret %d\n", ret);
         scsi_command_complete(r, ret);
@@ -172,27 +211,21 @@ static void scsi_read_complete(void * opaque, int ret)
     DPRINTF("Data ready tag=0x%x len=%d\n", r->req.tag, len);
 
     r->len = -1;
-    r->req.bus->complete(r->req.bus, SCSI_REASON_DATA, r->req.tag, len);
-    if (len == 0)
+    if (len == 0) {
         scsi_command_complete(r, 0);
+    } else {
+        scsi_req_data(&r->req, len);
+    }
 }
 
 /* Read more data from scsi device into buffer.  */
-static void scsi_read_data(SCSIDevice *d, uint32_t tag)
+static void scsi_read_data(SCSIRequest *req)
 {
-    SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, d);
-    SCSIGenericReq *r;
+    SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
+    SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, r->req.dev);
     int ret;
 
-    DPRINTF("scsi_read_data 0x%x\n", tag);
-    r = scsi_find_request(s, tag);
-    if (!r) {
-        BADF("Bad read tag 0x%x\n", tag);
-        /* ??? This is the wrong error.  */
-        scsi_command_complete(r, -EINVAL);
-        return;
-    }
-
+    DPRINTF("scsi_read_data 0x%x\n", req->tag);
     if (r->len == -1) {
         scsi_command_complete(r, 0);
         return;
@@ -210,13 +243,15 @@ static void scsi_read_data(SCSIDevice *d, uint32_t tag)
         DPRINTF("Sense: %d %d %d %d %d %d %d %d\n",
                 r->buf[0], r->buf[1], r->buf[2], r->buf[3],
                 r->buf[4], r->buf[5], r->buf[6], r->buf[7]);
-        r->req.bus->complete(r->req.bus, SCSI_REASON_DATA, r->req.tag, s->senselen);
+        scsi_req_data(&r->req, s->senselen);
+        /* Clear sensebuf after REQUEST_SENSE */
+        scsi_clear_sense(s);
         return;
     }
 
     ret = execute_command(s->bs, r, SG_DXFER_FROM_DEV, scsi_read_complete);
-    if (ret == -1) {
-        scsi_command_complete(r, -EINVAL);
+    if (ret < 0) {
+        scsi_command_complete(r, ret);
         return;
     }
 }
@@ -227,6 +262,7 @@ static void scsi_write_complete(void * opaque, int ret)
     SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, r->req.dev);
 
     DPRINTF("scsi_write_complete() ret = %d\n", ret);
+    r->req.aiocb = NULL;
     if (ret) {
         DPRINTF("IO error\n");
         scsi_command_complete(r, ret);
@@ -244,46 +280,30 @@ static void scsi_write_complete(void * opaque, int ret)
 
 /* Write data to a scsi device.  Returns nonzero on failure.
    The transfer may complete asynchronously.  */
-static int scsi_write_data(SCSIDevice *d, uint32_t tag)
+static void scsi_write_data(SCSIRequest *req)
 {
-    SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, d);
-    SCSIGenericReq *r;
+    SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, req->dev);
+    SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
     int ret;
 
-    DPRINTF("scsi_write_data 0x%x\n", tag);
-    r = scsi_find_request(s, tag);
-    if (!r) {
-        BADF("Bad write tag 0x%x\n", tag);
-        /* ??? This is the wrong error.  */
-        scsi_command_complete(r, -EINVAL);
-        return 0;
-    }
-
+    DPRINTF("scsi_write_data 0x%x\n", req->tag);
     if (r->len == 0) {
         r->len = r->buflen;
-        r->req.bus->complete(r->req.bus, SCSI_REASON_DATA, r->req.tag, r->len);
-        return 0;
+        scsi_req_data(&r->req, r->len);
+        return;
     }
 
     ret = execute_command(s->bs, r, SG_DXFER_TO_DEV, scsi_write_complete);
-    if (ret == -1) {
-        scsi_command_complete(r, -EINVAL);
-        return 1;
+    if (ret < 0) {
+        scsi_command_complete(r, ret);
     }
-
-    return 0;
 }
 
 /* Return a pointer to the data buffer.  */
-static uint8_t *scsi_get_buf(SCSIDevice *d, uint32_t tag)
+static uint8_t *scsi_get_buf(SCSIRequest *req)
 {
-    SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, d);
-    SCSIGenericReq *r;
-    r = scsi_find_request(s, tag);
-    if (!r) {
-        BADF("Bad buffer tag 0x%x\n", tag);
-        return NULL;
-    }
+    SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
+
     return r->buf;
 }
 
@@ -311,42 +331,23 @@ static void scsi_req_fixup(SCSIRequest *req)
    (eg. disk reads), negative for transfers to the device (eg. disk writes),
    and zero if the command does not transfer any data.  */
 
-static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
-                                 uint8_t *cmd, int lun)
+static int32_t scsi_send_command(SCSIRequest *req, uint8_t *cmd)
 {
-    SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, d);
-    SCSIGenericReq *r;
-    SCSIBus *bus;
+    SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, req->dev);
+    SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
     int ret;
 
-    if (cmd[0] != REQUEST_SENSE &&
-        (lun != s->lun || (cmd[1] >> 5) != s->lun)) {
-        DPRINTF("Unimplemented LUN %d\n", lun ? lun : cmd[1] >> 5);
-
-        s->sensebuf[0] = 0x70;
-        s->sensebuf[1] = 0x00;
-        s->sensebuf[2] = ILLEGAL_REQUEST;
-        s->sensebuf[3] = 0x00;
-        s->sensebuf[4] = 0x00;
-        s->sensebuf[5] = 0x00;
-        s->sensebuf[6] = 0x00;
-        s->senselen = 7;
-        s->driver_status = SG_ERR_DRIVER_SENSE;
-        bus = scsi_bus_from_device(d);
-        bus->complete(bus, SCSI_REASON_DONE, tag, CHECK_CONDITION);
+    if (cmd[0] != REQUEST_SENSE && req->lun != s->lun) {
+        DPRINTF("Unimplemented LUN %d\n", req->lun);
+        scsi_set_sense(s, SENSE_CODE(LUN_NOT_SUPPORTED));
+        r->req.status = CHECK_CONDITION;
+        scsi_req_complete(&r->req);
         return 0;
     }
 
-    r = scsi_find_request(s, tag);
-    if (r) {
-        BADF("Tag 0x%x already in use %p\n", tag, r);
-        scsi_cancel_io(d, tag);
-    }
-    r = scsi_new_request(d, tag, lun);
-
     if (-1 == scsi_req_parse(&r->req, cmd)) {
         BADF("Unsupported command length, command %x\n", cmd[0]);
-        scsi_remove_request(r);
+        scsi_command_complete(r, -EINVAL);
         return 0;
     }
     scsi_req_fixup(&r->req);
@@ -370,8 +371,8 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
         r->buflen = 0;
         r->buf = NULL;
         ret = execute_command(s->bs, r, SG_DXFER_NONE, scsi_command_complete);
-        if (ret == -1) {
-            scsi_command_complete(r, -EINVAL);
+        if (ret < 0) {
+            scsi_command_complete(r, ret);
             return 0;
         }
         return 0;
@@ -389,9 +390,9 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
     if (r->req.cmd.mode == SCSI_XFER_TO_DEV) {
         r->len = 0;
         return -r->req.cmd.xfer;
+    } else {
+        return r->req.cmd.xfer;
     }
-
-    return r->req.cmd.xfer;
 }
 
 static int get_blocksize(BlockDriverState *bdrv)
@@ -455,31 +456,18 @@ static int get_stream_blocksize(BlockDriverState *bdrv)
     return (buf[9] << 16) | (buf[10] << 8) | buf[11];
 }
 
-static void scsi_generic_purge_requests(SCSIGenericState *s)
-{
-    SCSIGenericReq *r;
-
-    while (!QTAILQ_EMPTY(&s->qdev.requests)) {
-        r = DO_UPCAST(SCSIGenericReq, req, QTAILQ_FIRST(&s->qdev.requests));
-        if (r->req.aiocb) {
-            bdrv_aio_cancel(r->req.aiocb);
-        }
-        scsi_remove_request(r);
-    }
-}
-
 static void scsi_generic_reset(DeviceState *dev)
 {
     SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev.qdev, dev);
 
-    scsi_generic_purge_requests(s);
+    scsi_device_purge_requests(&s->qdev);
 }
 
 static void scsi_destroy(SCSIDevice *d)
 {
     SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, d);
 
-    scsi_generic_purge_requests(s);
+    scsi_device_purge_requests(&s->qdev);
     blockdev_mark_auto_del(s->qdev.conf.bs);
 }
 
@@ -556,11 +544,14 @@ static SCSIDeviceInfo scsi_generic_info = {
     .qdev.reset   = scsi_generic_reset,
     .init         = scsi_generic_initfn,
     .destroy      = scsi_destroy,
+    .alloc_req    = scsi_new_request,
+    .free_req     = scsi_free_request,
     .send_command = scsi_send_command,
     .read_data    = scsi_read_data,
     .write_data   = scsi_write_data,
     .cancel_io    = scsi_cancel_io,
     .get_buf      = scsi_get_buf,
+    .get_sense    = scsi_get_sense,
     .qdev.props   = (Property[]) {
         DEFINE_BLOCK_PROPERTIES(SCSIGenericState, qdev.conf),
         DEFINE_PROP_END_OF_LIST(),
diff --git a/hw/scsi.h b/hw/scsi.h
index d3b5d56cd6..c1dca35b86 100644
--- a/hw/scsi.h
+++ b/hw/scsi.h
@@ -9,17 +9,11 @@
 
 #define SCSI_CMD_BUF_SIZE     16
 
-/* scsi-disk.c */
-enum scsi_reason {
-    SCSI_REASON_DONE, /* Command complete.  */
-    SCSI_REASON_DATA  /* Transfer complete, more data required.  */
-};
-
 typedef struct SCSIBus SCSIBus;
+typedef struct SCSIBusOps SCSIBusOps;
 typedef struct SCSIDevice SCSIDevice;
 typedef struct SCSIDeviceInfo SCSIDeviceInfo;
-typedef void (*scsi_completionfn)(SCSIBus *bus, int reason, uint32_t tag,
-                                  uint32_t arg);
+typedef struct SCSIRequest SCSIRequest;
 
 enum SCSIXferMode {
     SCSI_XFER_NONE,      /*  TEST_UNIT_READY, ...            */
@@ -27,9 +21,16 @@ enum SCSIXferMode {
     SCSI_XFER_TO_DEV,    /*  WRITE, MODE_SELECT, ...         */
 };
 
-typedef struct SCSIRequest {
+typedef struct SCSISense {
+    uint8_t key;
+    uint8_t asc;
+    uint8_t ascq;
+} SCSISense;
+
+struct SCSIRequest {
     SCSIBus           *bus;
     SCSIDevice        *dev;
+    uint32_t          refcount;
     uint32_t          tag;
     uint32_t          lun;
     uint32_t          status;
@@ -43,7 +44,7 @@ typedef struct SCSIRequest {
     BlockDriverAIOCB  *aiocb;
     bool enqueued;
     QTAILQ_ENTRY(SCSIRequest) next;
-} SCSIRequest;
+};
 
 struct SCSIDevice
 {
@@ -66,28 +67,34 @@ struct SCSIDeviceInfo {
     DeviceInfo qdev;
     scsi_qdev_initfn init;
     void (*destroy)(SCSIDevice *s);
-    int32_t (*send_command)(SCSIDevice *s, uint32_t tag, uint8_t *buf,
-                            int lun);
-    void (*read_data)(SCSIDevice *s, uint32_t tag);
-    int (*write_data)(SCSIDevice *s, uint32_t tag);
-    void (*cancel_io)(SCSIDevice *s, uint32_t tag);
-    uint8_t *(*get_buf)(SCSIDevice *s, uint32_t tag);
+    SCSIRequest *(*alloc_req)(SCSIDevice *s, uint32_t tag, uint32_t lun);
+    void (*free_req)(SCSIRequest *req);
+    int32_t (*send_command)(SCSIRequest *req, uint8_t *buf);
+    void (*read_data)(SCSIRequest *req);
+    void (*write_data)(SCSIRequest *req);
+    void (*cancel_io)(SCSIRequest *req);
+    uint8_t *(*get_buf)(SCSIRequest *req);
+    int (*get_sense)(SCSIRequest *req, uint8_t *buf, int len);
+};
+
+struct SCSIBusOps {
+    void (*transfer_data)(SCSIRequest *req, uint32_t arg);
+    void (*complete)(SCSIRequest *req, uint32_t arg);
+    void (*cancel)(SCSIRequest *req);
 };
 
-typedef void (*SCSIAttachFn)(DeviceState *host, BlockDriverState *bdrv,
-              int unit);
 struct SCSIBus {
     BusState qbus;
     int busnr;
 
     int tcq, ndev;
-    scsi_completionfn complete;
+    const SCSIBusOps *ops;
 
     SCSIDevice *devs[MAX_SCSI_DEVS];
 };
 
 void scsi_bus_new(SCSIBus *bus, DeviceState *host, int tcq, int ndev,
-                  scsi_completionfn complete);
+                  const SCSIBusOps *ops);
 void scsi_qdev_register(SCSIDeviceInfo *info);
 
 static inline SCSIBus *scsi_bus_from_device(SCSIDevice *d)
@@ -99,12 +106,54 @@ SCSIDevice *scsi_bus_legacy_add_drive(SCSIBus *bus, BlockDriverState *bdrv,
                                       int unit, bool removable);
 int scsi_bus_legacy_handle_cmdline(SCSIBus *bus);
 
+/*
+ * Predefined sense codes
+ */
+
+/* No sense data available */
+extern const struct SCSISense sense_code_NO_SENSE;
+/* LUN not ready, Manual intervention required */
+extern const struct SCSISense sense_code_LUN_NOT_READY;
+/* LUN not ready, Medium not present */
+extern const struct SCSISense sense_code_NO_MEDIUM;
+/* Hardware error, internal target failure */
+extern const struct SCSISense sense_code_TARGET_FAILURE;
+/* Illegal request, invalid command operation code */
+extern const struct SCSISense sense_code_INVALID_OPCODE;
+/* Illegal request, LBA out of range */
+extern const struct SCSISense sense_code_LBA_OUT_OF_RANGE;
+/* Illegal request, Invalid field in CDB */
+extern const struct SCSISense sense_code_INVALID_FIELD;
+/* Illegal request, LUN not supported */
+extern const struct SCSISense sense_code_LUN_NOT_SUPPORTED;
+/* Command aborted, I/O process terminated */
+extern const struct SCSISense sense_code_IO_ERROR;
+/* Command aborted, I_T Nexus loss occurred */
+extern const struct SCSISense sense_code_I_T_NEXUS_LOSS;
+/* Command aborted, Logical Unit failure */
+extern const struct SCSISense sense_code_LUN_FAILURE;
+
+#define SENSE_CODE(x) sense_code_ ## x
+
+int scsi_build_sense(SCSISense sense, uint8_t *buf, int len, int fixed);
+int scsi_sense_valid(SCSISense sense);
+
 SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag, uint32_t lun);
-SCSIRequest *scsi_req_find(SCSIDevice *d, uint32_t tag);
+SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun);
+int32_t scsi_req_enqueue(SCSIRequest *req, uint8_t *buf);
 void scsi_req_free(SCSIRequest *req);
+SCSIRequest *scsi_req_ref(SCSIRequest *req);
+void scsi_req_unref(SCSIRequest *req);
 
 int scsi_req_parse(SCSIRequest *req, uint8_t *buf);
 void scsi_req_print(SCSIRequest *req);
+void scsi_req_continue(SCSIRequest *req);
+void scsi_req_data(SCSIRequest *req, int len);
 void scsi_req_complete(SCSIRequest *req);
+uint8_t *scsi_req_get_buf(SCSIRequest *req);
+int scsi_req_get_sense(SCSIRequest *req, uint8_t *buf, int len);
+void scsi_req_abort(SCSIRequest *req, int status);
+void scsi_req_cancel(SCSIRequest *req);
+void scsi_device_purge_requests(SCSIDevice *sdev);
 
 #endif
diff --git a/hw/spapr_vscsi.c b/hw/spapr_vscsi.c
index 992833450c..1c901ef6eb 100644
--- a/hw/spapr_vscsi.c
+++ b/hw/spapr_vscsi.c
@@ -74,7 +74,7 @@ typedef struct vscsi_req {
     union viosrp_iu         iu;
 
     /* SCSI request tracking */
-    SCSIDevice              *sdev;
+    SCSIRequest             *sreq;
     uint32_t                qtag; /* qemu tag != srp tag */
     int                     lun;
     int                     active;
@@ -123,11 +123,16 @@ static struct vscsi_req *vscsi_get_req(VSCSIState *s)
 
 static void vscsi_put_req(VSCSIState *s, vscsi_req *req)
 {
+    if (req->sreq != NULL) {
+        scsi_req_unref(req->sreq);
+    }
+    req->sreq = NULL;
     req->active = 0;
 }
 
-static vscsi_req *vscsi_find_req(VSCSIState *s, uint32_t tag)
+static vscsi_req *vscsi_find_req(VSCSIState *s, SCSIRequest *req)
 {
+    uint32_t tag = req->tag;
     if (tag >= VSCSI_REQ_LIMIT || !s->reqs[tag].active) {
         return NULL;
     }
@@ -442,10 +447,18 @@ static int vscsi_preprocess_desc(vscsi_req *req)
 
 static void vscsi_send_request_sense(VSCSIState *s, vscsi_req *req)
 {
-    SCSIDevice *sdev = req->sdev;
     uint8_t *cdb = req->iu.srp.cmd.cdb;
     int n;
 
+    n = scsi_req_get_sense(req->sreq, req->sense, sizeof(req->sense));
+    if (n) {
+        req->senselen = n;
+        vscsi_send_rsp(s, req, CHECK_CONDITION, 0, 0);
+        vscsi_put_req(s, req);
+        return;
+    }
+
+    dprintf("VSCSI: Got CHECK_CONDITION, requesting sense...\n");
     cdb[0] = 3;
     cdb[1] = 0;
     cdb[2] = 0;
@@ -453,66 +466,92 @@ static void vscsi_send_request_sense(VSCSIState *s, vscsi_req *req)
     cdb[4] = 96;
     cdb[5] = 0;
     req->sensing = 1;
-    n = sdev->info->send_command(sdev, req->qtag, cdb, req->lun);
+    n = scsi_req_enqueue(req->sreq, cdb);
     dprintf("VSCSI: Queued request sense tag 0x%x\n", req->qtag);
     if (n < 0) {
         fprintf(stderr, "VSCSI: REQUEST_SENSE wants write data !?!?!?\n");
-        sdev->info->cancel_io(sdev, req->qtag);
         vscsi_makeup_sense(s, req, HARDWARE_ERROR, 0, 0);
-        vscsi_send_rsp(s, req, CHECK_CONDITION, 0, 0);
-        vscsi_put_req(s, req);
+        scsi_req_abort(req->sreq, CHECK_CONDITION);
         return;
     } else if (n == 0) {
         return;
     }
-    sdev->info->read_data(sdev, req->qtag);
+    scsi_req_continue(req->sreq);
 }
 
 /* Callback to indicate that the SCSI layer has completed a transfer.  */
-static void vscsi_command_complete(SCSIBus *bus, int reason, uint32_t tag,
-                                   uint32_t arg)
+static void vscsi_transfer_data(SCSIRequest *sreq, uint32_t len)
 {
-    VSCSIState *s = DO_UPCAST(VSCSIState, vdev.qdev, bus->qbus.parent);
-    vscsi_req *req = vscsi_find_req(s, tag);
-    SCSIDevice *sdev;
+    VSCSIState *s = DO_UPCAST(VSCSIState, vdev.qdev, sreq->bus->qbus.parent);
+    vscsi_req *req = vscsi_find_req(s, sreq);
     uint8_t *buf;
-    int32_t res_in = 0, res_out = 0;
-    int len, rc = 0;
+    int rc = 0;
 
-    dprintf("VSCSI: SCSI cmd complete, r=0x%x tag=0x%x arg=0x%x, req=%p\n",
-            reason, tag, arg, req);
+    dprintf("VSCSI: SCSI xfer complete tag=0x%x len=0x%x, req=%p\n",
+            sreq->tag, len, req);
     if (req == NULL) {
-        fprintf(stderr, "VSCSI: Can't find request for tag 0x%x\n", tag);
+        fprintf(stderr, "VSCSI: Can't find request for tag 0x%x\n", sreq->tag);
         return;
     }
-    sdev = req->sdev;
 
     if (req->sensing) {
-        if (reason == SCSI_REASON_DONE) {
-            dprintf("VSCSI: Sense done !\n");
-            vscsi_send_rsp(s, req, CHECK_CONDITION, 0, 0);
-            vscsi_put_req(s, req);
-        } else {
-            uint8_t *buf = sdev->info->get_buf(sdev, tag);
-
-            len = MIN(arg, SCSI_SENSE_BUF_SIZE);
-            dprintf("VSCSI: Sense data, %d bytes:\n", len);
-            dprintf("       %02x  %02x  %02x  %02x  %02x  %02x  %02x  %02x\n",
-                    buf[0], buf[1], buf[2], buf[3],
-                    buf[4], buf[5], buf[6], buf[7]);
-            dprintf("       %02x  %02x  %02x  %02x  %02x  %02x  %02x  %02x\n",
-                    buf[8], buf[9], buf[10], buf[11],
-                    buf[12], buf[13], buf[14], buf[15]);
-            memcpy(req->sense, buf, len);
-            req->senselen = len;
-            sdev->info->read_data(sdev, req->qtag);
-        }
+        uint8_t *buf = scsi_req_get_buf(sreq);
+
+        len = MIN(len, SCSI_SENSE_BUF_SIZE);
+        dprintf("VSCSI: Sense data, %d bytes:\n", len);
+        dprintf("       %02x  %02x  %02x  %02x  %02x  %02x  %02x  %02x\n",
+                buf[0], buf[1], buf[2], buf[3],
+                buf[4], buf[5], buf[6], buf[7]);
+        dprintf("       %02x  %02x  %02x  %02x  %02x  %02x  %02x  %02x\n",
+                buf[8], buf[9], buf[10], buf[11],
+                buf[12], buf[13], buf[14], buf[15]);
+        memcpy(req->sense, buf, len);
+        req->senselen = len;
+        scsi_req_continue(req->sreq);
+        return;
+    }
+
+    if (len) {
+        buf = scsi_req_get_buf(sreq);
+        rc = vscsi_srp_transfer_data(s, req, req->writing, buf, len);
+    }
+    if (rc < 0) {
+        fprintf(stderr, "VSCSI: RDMA error rc=%d!\n", rc);
+        vscsi_makeup_sense(s, req, HARDWARE_ERROR, 0, 0);
+        scsi_req_abort(req->sreq, CHECK_CONDITION);
+        return;
+    }
+
+    /* Start next chunk */
+    req->data_len -= rc;
+    scsi_req_continue(sreq);
+}
+
+/* Callback to indicate that the SCSI layer has completed a transfer.  */
+static void vscsi_command_complete(SCSIRequest *sreq, uint32_t status)
+{
+    VSCSIState *s = DO_UPCAST(VSCSIState, vdev.qdev, sreq->bus->qbus.parent);
+    vscsi_req *req = vscsi_find_req(s, sreq);
+    int32_t res_in = 0, res_out = 0;
+
+    dprintf("VSCSI: SCSI cmd complete, r=0x%x tag=0x%x status=0x%x, req=%p\n",
+            reason, sreq->tag, status, req);
+    if (req == NULL) {
+        fprintf(stderr, "VSCSI: Can't find request for tag 0x%x\n", sreq->tag);
+        return;
+    }
+
+    if (!req->sensing && status == CHECK_CONDITION) {
+        vscsi_send_request_sense(s, req);
         return;
     }
 
-    if (reason == SCSI_REASON_DONE) {
-        dprintf("VSCSI: Command complete err=%d\n", arg);
-        if (arg == 0) {
+    if (req->sensing) {
+        dprintf("VSCSI: Sense done !\n");
+        status = CHECK_CONDITION;
+    } else {
+        dprintf("VSCSI: Command complete err=%d\n", status);
+        if (status == 0) {
             /* We handle overflows, not underflows for normal commands,
              * but hopefully nobody cares
              */
@@ -521,41 +560,18 @@ static void vscsi_command_complete(SCSIBus *bus, int reason, uint32_t tag,
             } else {
                 res_in = req->data_len;
             }
-            vscsi_send_rsp(s, req, 0, res_in, res_out);
-        } else if (arg == CHECK_CONDITION) {
-            dprintf("VSCSI: Got CHECK_CONDITION, requesting sense...\n");
-            vscsi_send_request_sense(s, req);
-            return;
-        } else {
-            vscsi_send_rsp(s, req, arg, 0, 0);
         }
-        vscsi_put_req(s, req);
-        return;
     }
+    vscsi_send_rsp(s, req, 0, res_in, res_out);
+    vscsi_put_req(s, req);
+}
 
-    /* "arg" is how much we have read for reads and how much we want
-     * to write for writes (ie, how much is to be DMA'd)
-     */
-    if (arg) {
-        buf = sdev->info->get_buf(sdev, tag);
-        rc = vscsi_srp_transfer_data(s, req, req->writing, buf, arg);
-    }
-    if (rc < 0) {
-        fprintf(stderr, "VSCSI: RDMA error rc=%d!\n", rc);
-        sdev->info->cancel_io(sdev, req->qtag);
-        vscsi_makeup_sense(s, req, HARDWARE_ERROR, 0, 0);
-        vscsi_send_rsp(s, req, CHECK_CONDITION, 0, 0);
-        vscsi_put_req(s, req);
-        return;
-    }
+static void vscsi_request_cancelled(SCSIRequest *sreq)
+{
+    VSCSIState *s = DO_UPCAST(VSCSIState, vdev.qdev, sreq->bus->qbus.parent);
+    vscsi_req *req = vscsi_find_req(s, sreq);
 
-    /* Start next chunk */
-    req->data_len -= rc;
-    if (req->writing) {
-        sdev->info->write_data(sdev, req->qtag);
-    } else {
-        sdev->info->read_data(sdev, req->qtag);
-    }
+    vscsi_put_req(s, req);
 }
 
 static void vscsi_process_login(VSCSIState *s, vscsi_req *req)
@@ -642,9 +658,9 @@ static int vscsi_queue_cmd(VSCSIState *s, vscsi_req *req)
         } return 1;
     }
 
-    req->sdev = sdev;
     req->lun = lun;
-    n = sdev->info->send_command(sdev, req->qtag, srp->cmd.cdb, lun);
+    req->sreq = scsi_req_new(sdev, req->qtag, lun);
+    n = scsi_req_enqueue(req->sreq, srp->cmd.cdb);
 
     dprintf("VSCSI: Queued command tag 0x%x CMD 0x%x ID %d LUN %d ret: %d\n",
             req->qtag, srp->cmd.cdb[0], id, lun, n);
@@ -657,15 +673,14 @@ static int vscsi_queue_cmd(VSCSIState *s, vscsi_req *req)
 
         /* Preprocess RDMA descriptors */
         vscsi_preprocess_desc(req);
-    }
 
-    /* Get transfer direction and initiate transfer */
-    if (n > 0) {
-        req->data_len = n;
-        sdev->info->read_data(sdev, req->qtag);
-    } else if (n < 0) {
-        req->data_len = -n;
-        sdev->info->write_data(sdev, req->qtag);
+        /* Get transfer direction and initiate transfer */
+        if (n > 0) {
+            req->data_len = n;
+        } else if (n < 0) {
+            req->data_len = -n;
+        }
+        scsi_req_continue(req->sreq);
     }
     /* Don't touch req here, it may have been recycled already */
 
@@ -907,6 +922,12 @@ static int vscsi_do_crq(struct VIOsPAPRDevice *dev, uint8_t *crq_data)
     return 0;
 }
 
+static const struct SCSIBusOps vscsi_scsi_ops = {
+    .transfer_data = vscsi_transfer_data,
+    .complete = vscsi_command_complete,
+    .cancel = vscsi_request_cancelled
+};
+
 static int spapr_vscsi_init(VIOsPAPRDevice *dev)
 {
     VSCSIState *s = DO_UPCAST(VSCSIState, vdev, dev);
@@ -923,7 +944,7 @@ static int spapr_vscsi_init(VIOsPAPRDevice *dev)
     dev->crq.SendFunc = vscsi_do_crq;
 
     scsi_bus_new(&s->bus, &dev->qdev, 1, VSCSI_REQ_LIMIT,
-                 vscsi_command_complete);
+                 &vscsi_scsi_ops);
     if (!dev->qdev.hotplugged) {
         scsi_bus_legacy_handle_cmdline(&s->bus);
     }
diff --git a/hw/usb-bt.c b/hw/usb-bt.c
index 22e6845049..baae4876ea 100644
--- a/hw/usb-bt.c
+++ b/hw/usb-bt.c
@@ -372,13 +372,13 @@ static void usb_bt_handle_reset(USBDevice *dev)
     s->altsetting = 0;
 }
 
-static int usb_bt_handle_control(USBDevice *dev, int request, int value,
-                int index, int length, uint8_t *data)
+static int usb_bt_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     struct USBBtState *s = (struct USBBtState *) dev->opaque;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         switch (request) {
         case DeviceRequest | USB_REQ_GET_CONFIGURATION:
diff --git a/hw/usb-ccid.c b/hw/usb-ccid.c
index 079b4a2555..5b6878bea4 100644
--- a/hw/usb-ccid.c
+++ b/hw/usb-ccid.c
@@ -602,8 +602,8 @@ static void ccid_handle_reset(USBDevice *dev)
     ccid_reset(s);
 }
 
-static int ccid_handle_control(USBDevice *dev, int request, int value,
-                                  int index, int length, uint8_t *data)
+static int ccid_handle_control(USBDevice *dev, USBPacket *p, int request,
+                               int value, int index, int length, uint8_t *data)
 {
     USBCCIDState *s = DO_UPCAST(USBCCIDState, dev, dev);
     int ret = 0;
diff --git a/hw/usb-desc.c b/hw/usb-desc.c
index 62591f20aa..e4a4680fee 100644
--- a/hw/usb-desc.c
+++ b/hw/usb-desc.c
@@ -76,7 +76,7 @@ int usb_desc_config(const USBDescConfig *conf, uint8_t *dest, size_t len)
 {
     uint8_t  bLength = 0x09;
     uint16_t wTotalLength = 0;
-    int i, rc, count;
+    int i, rc;
 
     if (len < bLength) {
         return -1;
@@ -91,8 +91,19 @@ int usb_desc_config(const USBDescConfig *conf, uint8_t *dest, size_t len)
     dest[0x08] = conf->bMaxPower;
     wTotalLength += bLength;
 
-    count = conf->nif ? conf->nif : conf->bNumInterfaces;
-    for (i = 0; i < count; i++) {
+    /* handle grouped interfaces if any*/
+    for (i = 0; i < conf->nif_groups; i++) {
+        rc = usb_desc_iface_group(&(conf->if_groups[i]),
+                                  dest + wTotalLength,
+                                  len - wTotalLength);
+        if (rc < 0) {
+            return rc;
+        }
+        wTotalLength += rc;
+    }
+
+    /* handle normal (ungrouped / no IAD) interfaces if any */
+    for (i = 0; i < conf->nif; i++) {
         rc = usb_desc_iface(conf->ifs + i, dest + wTotalLength, len - wTotalLength);
         if (rc < 0) {
             return rc;
@@ -105,6 +116,41 @@ int usb_desc_config(const USBDescConfig *conf, uint8_t *dest, size_t len)
     return wTotalLength;
 }
 
+int usb_desc_iface_group(const USBDescIfaceAssoc *iad, uint8_t *dest,
+                         size_t len)
+{
+    int pos = 0;
+    int i = 0;
+
+    /* handle interface association descriptor */
+    uint8_t bLength = 0x08;
+
+    if (len < bLength) {
+        return -1;
+    }
+
+    dest[0x00] = bLength;
+    dest[0x01] = USB_DT_INTERFACE_ASSOC;
+    dest[0x02] = iad->bFirstInterface;
+    dest[0x03] = iad->bInterfaceCount;
+    dest[0x04] = iad->bFunctionClass;
+    dest[0x05] = iad->bFunctionSubClass;
+    dest[0x06] = iad->bFunctionProtocol;
+    dest[0x07] = iad->iFunction;
+    pos += bLength;
+
+    /* handle associated interfaces in this group */
+    for (i = 0; i < iad->nif; i++) {
+        int rc = usb_desc_iface(&(iad->ifs[i]), dest + pos, len - pos);
+        if (rc < 0) {
+            return rc;
+        }
+        pos += rc;
+    }
+
+    return pos;
+}
+
 int usb_desc_iface(const USBDescIface *iface, uint8_t *dest, size_t len)
 {
     uint8_t bLength = 0x09;
@@ -344,8 +390,8 @@ int usb_desc_get_descriptor(USBDevice *dev, int value, uint8_t *dest, size_t len
     return ret;
 }
 
-int usb_desc_handle_control(USBDevice *dev, int request, int value,
-                            int index, int length, uint8_t *data)
+int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
+        int request, int value, int index, int length, uint8_t *data)
 {
     const USBDesc *desc = dev->info->usb_desc;
     int i, ret = -1;
diff --git a/hw/usb-desc.h b/hw/usb-desc.h
index ac734ab088..9d7ed599ce 100644
--- a/hw/usb-desc.h
+++ b/hw/usb-desc.h
@@ -30,6 +30,24 @@ struct USBDescConfig {
     uint8_t                   bmAttributes;
     uint8_t                   bMaxPower;
 
+    /* grouped interfaces */
+    uint8_t                   nif_groups;
+    const USBDescIfaceAssoc   *if_groups;
+
+    /* "normal" interfaces */
+    uint8_t                   nif;
+    const USBDescIface        *ifs;
+};
+
+/* conceptually an Interface Association Descriptor, and releated interfaces */
+struct USBDescIfaceAssoc {
+    uint8_t                   bFirstInterface;
+    uint8_t                   bInterfaceCount;
+    uint8_t                   bFunctionClass;
+    uint8_t                   bFunctionSubClass;
+    uint8_t                   bFunctionProtocol;
+    uint8_t                   iFunction;
+
     uint8_t                   nif;
     const USBDescIface        *ifs;
 };
@@ -75,6 +93,8 @@ int usb_desc_device(const USBDescID *id, const USBDescDevice *dev,
 int usb_desc_device_qualifier(const USBDescDevice *dev,
                               uint8_t *dest, size_t len);
 int usb_desc_config(const USBDescConfig *conf, uint8_t *dest, size_t len);
+int usb_desc_iface_group(const USBDescIfaceAssoc *iad, uint8_t *dest,
+                         size_t len);
 int usb_desc_iface(const USBDescIface *iface, uint8_t *dest, size_t len);
 int usb_desc_endpoint(const USBDescEndpoint *ep, uint8_t *dest, size_t len);
 int usb_desc_other(const USBDescOther *desc, uint8_t *dest, size_t len);
@@ -86,7 +106,7 @@ void usb_desc_set_string(USBDevice *dev, uint8_t index, const char *str);
 const char *usb_desc_get_string(USBDevice *dev, uint8_t index);
 int usb_desc_string(USBDevice *dev, int index, uint8_t *dest, size_t len);
 int usb_desc_get_descriptor(USBDevice *dev, int value, uint8_t *dest, size_t len);
-int usb_desc_handle_control(USBDevice *dev, int request, int value,
-                            int index, int length, uint8_t *data);
+int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
+        int request, int value, int index, int length, uint8_t *data);
 
 #endif /* QEMU_HW_USB_DESC_H */
diff --git a/hw/usb-ehci.c b/hw/usb-ehci.c
new file mode 100644
index 0000000000..f63519ecf9
--- /dev/null
+++ b/hw/usb-ehci.c
@@ -0,0 +1,2037 @@
+/*
+ * QEMU USB EHCI Emulation
+ *
+ * Copyright(c) 2008  Emutex Ltd. (address@hidden)
+ *
+ * EHCI project was started by Mark Burkley, with contributions by
+ * Niels de Vos.  David S. Ahern continued working on it.  Kevin Wolf,
+ * Jan Kiszka and Vincent Palatin contributed bugfixes.
+ *
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or(at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * TODO:
+ *  o Downstream port handoff
+ */
+
+#include "hw.h"
+#include "qemu-timer.h"
+#include "usb.h"
+#include "pci.h"
+#include "monitor.h"
+
+#define EHCI_DEBUG   0
+#define STATE_DEBUG  0       /* state transitions  */
+
+#if EHCI_DEBUG || STATE_DEBUG
+#define DPRINTF printf
+#else
+#define DPRINTF(...)
+#endif
+
+#if STATE_DEBUG
+#define DPRINTF_ST DPRINTF
+#else
+#define DPRINTF_ST(...)
+#endif
+
+/* internal processing - reset HC to try and recover */
+#define USB_RET_PROCERR   (-99)
+
+#define MMIO_SIZE        0x1000
+
+/* Capability Registers Base Address - section 2.2 */
+#define CAPREGBASE       0x0000
+#define CAPLENGTH        CAPREGBASE + 0x0000  // 1-byte, 0x0001 reserved
+#define HCIVERSION       CAPREGBASE + 0x0002  // 2-bytes, i/f version #
+#define HCSPARAMS        CAPREGBASE + 0x0004  // 4-bytes, structural params
+#define HCCPARAMS        CAPREGBASE + 0x0008  // 4-bytes, capability params
+#define EECP             HCCPARAMS + 1
+#define HCSPPORTROUTE1   CAPREGBASE + 0x000c
+#define HCSPPORTROUTE2   CAPREGBASE + 0x0010
+
+#define OPREGBASE        0x0020        // Operational Registers Base Address
+
+#define USBCMD           OPREGBASE + 0x0000
+#define USBCMD_RUNSTOP   (1 << 0)      // run / Stop
+#define USBCMD_HCRESET   (1 << 1)      // HC Reset
+#define USBCMD_FLS       (3 << 2)      // Frame List Size
+#define USBCMD_FLS_SH    2             // Frame List Size Shift
+#define USBCMD_PSE       (1 << 4)      // Periodic Schedule Enable
+#define USBCMD_ASE       (1 << 5)      // Asynch Schedule Enable
+#define USBCMD_IAAD      (1 << 6)      // Int Asynch Advance Doorbell
+#define USBCMD_LHCR      (1 << 7)      // Light Host Controller Reset
+#define USBCMD_ASPMC     (3 << 8)      // Async Sched Park Mode Count
+#define USBCMD_ASPME     (1 << 11)     // Async Sched Park Mode Enable
+#define USBCMD_ITC       (0x7f << 16)  // Int Threshold Control
+#define USBCMD_ITC_SH    16            // Int Threshold Control Shift
+
+#define USBSTS           OPREGBASE + 0x0004
+#define USBSTS_RO_MASK   0x0000003f
+#define USBSTS_INT       (1 << 0)      // USB Interrupt
+#define USBSTS_ERRINT    (1 << 1)      // Error Interrupt
+#define USBSTS_PCD       (1 << 2)      // Port Change Detect
+#define USBSTS_FLR       (1 << 3)      // Frame List Rollover
+#define USBSTS_HSE       (1 << 4)      // Host System Error
+#define USBSTS_IAA       (1 << 5)      // Interrupt on Async Advance
+#define USBSTS_HALT      (1 << 12)     // HC Halted
+#define USBSTS_REC       (1 << 13)     // Reclamation
+#define USBSTS_PSS       (1 << 14)     // Periodic Schedule Status
+#define USBSTS_ASS       (1 << 15)     // Asynchronous Schedule Status
+
+/*
+ *  Interrupt enable bits correspond to the interrupt active bits in USBSTS
+ *  so no need to redefine here.
+ */
+#define USBINTR              OPREGBASE + 0x0008
+#define USBINTR_MASK         0x0000003f
+
+#define FRINDEX              OPREGBASE + 0x000c
+#define CTRLDSSEGMENT        OPREGBASE + 0x0010
+#define PERIODICLISTBASE     OPREGBASE + 0x0014
+#define ASYNCLISTADDR        OPREGBASE + 0x0018
+#define ASYNCLISTADDR_MASK   0xffffffe0
+
+#define CONFIGFLAG           OPREGBASE + 0x0040
+
+#define PORTSC               (OPREGBASE + 0x0044)
+#define PORTSC_BEGIN         PORTSC
+#define PORTSC_END           (PORTSC + 4 * NB_PORTS)
+/*
+ * Bits that are reserverd or are read-only are masked out of values
+ * written to us by software
+ */
+#define PORTSC_RO_MASK       0x007021c5
+#define PORTSC_RWC_MASK      0x0000002a
+#define PORTSC_WKOC_E        (1 << 22)    // Wake on Over Current Enable
+#define PORTSC_WKDS_E        (1 << 21)    // Wake on Disconnect Enable
+#define PORTSC_WKCN_E        (1 << 20)    // Wake on Connect Enable
+#define PORTSC_PTC           (15 << 16)   // Port Test Control
+#define PORTSC_PTC_SH        16           // Port Test Control shift
+#define PORTSC_PIC           (3 << 14)    // Port Indicator Control
+#define PORTSC_PIC_SH        14           // Port Indicator Control Shift
+#define PORTSC_POWNER        (1 << 13)    // Port Owner
+#define PORTSC_PPOWER        (1 << 12)    // Port Power
+#define PORTSC_LINESTAT      (3 << 10)    // Port Line Status
+#define PORTSC_LINESTAT_SH   10           // Port Line Status Shift
+#define PORTSC_PRESET        (1 << 8)     // Port Reset
+#define PORTSC_SUSPEND       (1 << 7)     // Port Suspend
+#define PORTSC_FPRES         (1 << 6)     // Force Port Resume
+#define PORTSC_OCC           (1 << 5)     // Over Current Change
+#define PORTSC_OCA           (1 << 4)     // Over Current Active
+#define PORTSC_PEDC          (1 << 3)     // Port Enable/Disable Change
+#define PORTSC_PED           (1 << 2)     // Port Enable/Disable
+#define PORTSC_CSC           (1 << 1)     // Connect Status Change
+#define PORTSC_CONNECT       (1 << 0)     // Current Connect Status
+
+#define FRAME_TIMER_FREQ 1000
+#define FRAME_TIMER_USEC (1000000 / FRAME_TIMER_FREQ)
+
+#define NB_MAXINTRATE    8        // Max rate at which controller issues ints
+#define NB_PORTS         4        // Number of downstream ports
+#define BUFF_SIZE        5*4096   // Max bytes to transfer per transaction
+#define MAX_ITERATIONS   20       // Max number of QH before we break the loop
+#define MAX_QH           100      // Max allowable queue heads in a chain
+
+/*  Internal periodic / asynchronous schedule state machine states
+ */
+typedef enum {
+    EST_INACTIVE = 1000,
+    EST_ACTIVE,
+    EST_EXECUTING,
+    EST_SLEEPING,
+    /*  The following states are internal to the state machine function
+    */
+    EST_WAITLISTHEAD,
+    EST_FETCHENTRY,
+    EST_FETCHQH,
+    EST_FETCHITD,
+    EST_ADVANCEQUEUE,
+    EST_FETCHQTD,
+    EST_EXECUTE,
+    EST_WRITEBACK,
+    EST_HORIZONTALQH
+} EHCI_STATES;
+
+/* macros for accessing fields within next link pointer entry */
+#define NLPTR_GET(x)             ((x) & 0xffffffe0)
+#define NLPTR_TYPE_GET(x)        (((x) >> 1) & 3)
+#define NLPTR_TBIT(x)            ((x) & 1)  // 1=invalid, 0=valid
+
+/* link pointer types */
+#define NLPTR_TYPE_ITD           0     // isoc xfer descriptor
+#define NLPTR_TYPE_QH            1     // queue head
+#define NLPTR_TYPE_STITD         2     // split xaction, isoc xfer descriptor
+#define NLPTR_TYPE_FSTN          3     // frame span traversal node
+
+
+/*  EHCI spec version 1.0 Section 3.3
+ */
+typedef struct EHCIitd {
+    uint32_t next;
+
+    uint32_t transact[8];
+#define ITD_XACT_ACTIVE          (1 << 31)
+#define ITD_XACT_DBERROR         (1 << 30)
+#define ITD_XACT_BABBLE          (1 << 29)
+#define ITD_XACT_XACTERR         (1 << 28)
+#define ITD_XACT_LENGTH_MASK     0x0fff0000
+#define ITD_XACT_LENGTH_SH       16
+#define ITD_XACT_IOC             (1 << 15)
+#define ITD_XACT_PGSEL_MASK      0x00007000
+#define ITD_XACT_PGSEL_SH        12
+#define ITD_XACT_OFFSET_MASK     0x00000fff
+
+    uint32_t bufptr[7];
+#define ITD_BUFPTR_MASK          0xfffff000
+#define ITD_BUFPTR_SH            12
+#define ITD_BUFPTR_EP_MASK       0x00000f00
+#define ITD_BUFPTR_EP_SH         8
+#define ITD_BUFPTR_DEVADDR_MASK  0x0000007f
+#define ITD_BUFPTR_DEVADDR_SH    0
+#define ITD_BUFPTR_DIRECTION     (1 << 11)
+#define ITD_BUFPTR_MAXPKT_MASK   0x000007ff
+#define ITD_BUFPTR_MAXPKT_SH     0
+#define ITD_BUFPTR_MULT_MASK     0x00000003
+} EHCIitd;
+
+/*  EHCI spec version 1.0 Section 3.4
+ */
+typedef struct EHCIsitd {
+    uint32_t next;                  // Standard next link pointer
+    uint32_t epchar;
+#define SITD_EPCHAR_IO              (1 << 31)
+#define SITD_EPCHAR_PORTNUM_MASK    0x7f000000
+#define SITD_EPCHAR_PORTNUM_SH      24
+#define SITD_EPCHAR_HUBADD_MASK     0x007f0000
+#define SITD_EPCHAR_HUBADDR_SH      16
+#define SITD_EPCHAR_EPNUM_MASK      0x00000f00
+#define SITD_EPCHAR_EPNUM_SH        8
+#define SITD_EPCHAR_DEVADDR_MASK    0x0000007f
+
+    uint32_t uframe;
+#define SITD_UFRAME_CMASK_MASK      0x0000ff00
+#define SITD_UFRAME_CMASK_SH        8
+#define SITD_UFRAME_SMASK_MASK      0x000000ff
+
+    uint32_t results;
+#define SITD_RESULTS_IOC              (1 << 31)
+#define SITD_RESULTS_PGSEL            (1 << 30)
+#define SITD_RESULTS_TBYTES_MASK      0x03ff0000
+#define SITD_RESULTS_TYBYTES_SH       16
+#define SITD_RESULTS_CPROGMASK_MASK   0x0000ff00
+#define SITD_RESULTS_CPROGMASK_SH     8
+#define SITD_RESULTS_ACTIVE           (1 << 7)
+#define SITD_RESULTS_ERR              (1 << 6)
+#define SITD_RESULTS_DBERR            (1 << 5)
+#define SITD_RESULTS_BABBLE           (1 << 4)
+#define SITD_RESULTS_XACTERR          (1 << 3)
+#define SITD_RESULTS_MISSEDUF         (1 << 2)
+#define SITD_RESULTS_SPLITXSTATE      (1 << 1)
+
+    uint32_t bufptr[2];
+#define SITD_BUFPTR_MASK              0xfffff000
+#define SITD_BUFPTR_CURROFF_MASK      0x00000fff
+#define SITD_BUFPTR_TPOS_MASK         0x00000018
+#define SITD_BUFPTR_TPOS_SH           3
+#define SITD_BUFPTR_TCNT_MASK         0x00000007
+
+    uint32_t backptr;                 // Standard next link pointer
+} EHCIsitd;
+
+/*  EHCI spec version 1.0 Section 3.5
+ */
+typedef struct EHCIqtd {
+    uint32_t next;                    // Standard next link pointer
+    uint32_t altnext;                 // Standard next link pointer
+    uint32_t token;
+#define QTD_TOKEN_DTOGGLE             (1 << 31)
+#define QTD_TOKEN_TBYTES_MASK         0x7fff0000
+#define QTD_TOKEN_TBYTES_SH           16
+#define QTD_TOKEN_IOC                 (1 << 15)
+#define QTD_TOKEN_CPAGE_MASK          0x00007000
+#define QTD_TOKEN_CPAGE_SH            12
+#define QTD_TOKEN_CERR_MASK           0x00000c00
+#define QTD_TOKEN_CERR_SH             10
+#define QTD_TOKEN_PID_MASK            0x00000300
+#define QTD_TOKEN_PID_SH              8
+#define QTD_TOKEN_ACTIVE              (1 << 7)
+#define QTD_TOKEN_HALT                (1 << 6)
+#define QTD_TOKEN_DBERR               (1 << 5)
+#define QTD_TOKEN_BABBLE              (1 << 4)
+#define QTD_TOKEN_XACTERR             (1 << 3)
+#define QTD_TOKEN_MISSEDUF            (1 << 2)
+#define QTD_TOKEN_SPLITXSTATE         (1 << 1)
+#define QTD_TOKEN_PING                (1 << 0)
+
+    uint32_t bufptr[5];               // Standard buffer pointer
+#define QTD_BUFPTR_MASK               0xfffff000
+} EHCIqtd;
+
+/*  EHCI spec version 1.0 Section 3.6
+ */
+typedef struct EHCIqh {
+    uint32_t next;                    // Standard next link pointer
+
+    /* endpoint characteristics */
+    uint32_t epchar;
+#define QH_EPCHAR_RL_MASK             0xf0000000
+#define QH_EPCHAR_RL_SH               28
+#define QH_EPCHAR_C                   (1 << 27)
+#define QH_EPCHAR_MPLEN_MASK          0x07FF0000
+#define QH_EPCHAR_MPLEN_SH            16
+#define QH_EPCHAR_H                   (1 << 15)
+#define QH_EPCHAR_DTC                 (1 << 14)
+#define QH_EPCHAR_EPS_MASK            0x00003000
+#define QH_EPCHAR_EPS_SH              12
+#define EHCI_QH_EPS_FULL              0
+#define EHCI_QH_EPS_LOW               1
+#define EHCI_QH_EPS_HIGH              2
+#define EHCI_QH_EPS_RESERVED          3
+
+#define QH_EPCHAR_EP_MASK             0x00000f00
+#define QH_EPCHAR_EP_SH               8
+#define QH_EPCHAR_I                   (1 << 7)
+#define QH_EPCHAR_DEVADDR_MASK        0x0000007f
+#define QH_EPCHAR_DEVADDR_SH          0
+
+    /* endpoint capabilities */
+    uint32_t epcap;
+#define QH_EPCAP_MULT_MASK            0xc0000000
+#define QH_EPCAP_MULT_SH              30
+#define QH_EPCAP_PORTNUM_MASK         0x3f800000
+#define QH_EPCAP_PORTNUM_SH           23
+#define QH_EPCAP_HUBADDR_MASK         0x007f0000
+#define QH_EPCAP_HUBADDR_SH           16
+#define QH_EPCAP_CMASK_MASK           0x0000ff00
+#define QH_EPCAP_CMASK_SH             8
+#define QH_EPCAP_SMASK_MASK           0x000000ff
+#define QH_EPCAP_SMASK_SH             0
+
+    uint32_t current_qtd;             // Standard next link pointer
+    uint32_t next_qtd;                // Standard next link pointer
+    uint32_t altnext_qtd;
+#define QH_ALTNEXT_NAKCNT_MASK        0x0000001e
+#define QH_ALTNEXT_NAKCNT_SH          1
+
+    uint32_t token;                   // Same as QTD token
+    uint32_t bufptr[5];               // Standard buffer pointer
+#define BUFPTR_CPROGMASK_MASK         0x000000ff
+#define BUFPTR_FRAMETAG_MASK          0x0000001f
+#define BUFPTR_SBYTES_MASK            0x00000fe0
+#define BUFPTR_SBYTES_SH              5
+} EHCIqh;
+
+/*  EHCI spec version 1.0 Section 3.7
+ */
+typedef struct EHCIfstn {
+    uint32_t next;                    // Standard next link pointer
+    uint32_t backptr;                 // Standard next link pointer
+} EHCIfstn;
+
+typedef struct {
+    PCIDevice dev;
+    qemu_irq irq;
+    target_phys_addr_t mem_base;
+    int mem;
+    int num_ports;
+    /*
+     *  EHCI spec version 1.0 Section 2.3
+     *  Host Controller Operational Registers
+     */
+    union {
+        uint8_t mmio[MMIO_SIZE];
+        struct {
+            uint8_t cap[OPREGBASE];
+            uint32_t usbcmd;
+            uint32_t usbsts;
+            uint32_t usbintr;
+            uint32_t frindex;
+            uint32_t ctrldssegment;
+            uint32_t periodiclistbase;
+            uint32_t asynclistaddr;
+            uint32_t notused[9];
+            uint32_t configflag;
+            uint32_t portsc[NB_PORTS];
+        };
+    };
+    /*
+     *  Internal states, shadow registers, etc
+     */
+    uint32_t sofv;
+    QEMUTimer *frame_timer;
+    int attach_poll_counter;
+    int astate;                        // Current state in asynchronous schedule
+    int pstate;                        // Current state in periodic schedule
+    USBPort ports[NB_PORTS];
+    uint8_t buffer[BUFF_SIZE];
+    uint32_t usbsts_pending;
+
+    /* cached data from guest - needs to be flushed
+     * when guest removes an entry (doorbell, handshake sequence)
+     */
+    EHCIqh qh;             // copy of current QH (being worked on)
+    uint32_t qhaddr;       // address QH read from
+
+    EHCIqtd qtd;           // copy of current QTD (being worked on)
+    uint32_t qtdaddr;      // address QTD read from
+
+    uint32_t itdaddr;      // current ITD
+
+    uint32_t fetch_addr;   // which address to look at next
+
+    USBBus bus;
+    USBPacket usb_packet;
+    int async_complete;
+    uint32_t tbytes;
+    int pid;
+    int exec_status;
+    int isoch_pause;
+    uint32_t last_run_usec;
+    uint32_t frame_end_usec;
+} EHCIState;
+
+#define SET_LAST_RUN_CLOCK(s) \
+    (s)->last_run_usec = qemu_get_clock_ns(vm_clock) / 1000;
+
+/* nifty macros from Arnon's EHCI version  */
+#define get_field(data, field) \
+    (((data) & field##_MASK) >> field##_SH)
+
+#define set_field(data, newval, field) do { \
+    uint32_t val = *data; \
+    val &= ~ field##_MASK; \
+    val |= ((newval) << field##_SH) & field##_MASK; \
+    *data = val; \
+    } while(0)
+
+
+#if EHCI_DEBUG
+static const char *addr2str(unsigned addr)
+{
+    const char *r            = "   unknown";
+    const char *n[] = {
+        [ CAPLENGTH ]        = " CAPLENGTH",
+        [ HCIVERSION ]       = "HCIVERSION",
+        [ HCSPARAMS ]        = " HCSPARAMS",
+        [ HCCPARAMS ]        = " HCCPARAMS",
+        [ USBCMD ]           = "   COMMAND",
+        [ USBSTS ]           = "    STATUS",
+        [ USBINTR ]          = " INTERRUPT",
+        [ FRINDEX ]          = " FRAME IDX",
+        [ PERIODICLISTBASE ] = "P-LIST BASE",
+        [ ASYNCLISTADDR ]    = "A-LIST ADDR",
+        [ PORTSC_BEGIN ...
+          PORTSC_END ]       = "PORT STATUS",
+        [ CONFIGFLAG ]       = "CONFIG FLAG",
+    };
+
+    if (addr < ARRAY_SIZE(n) && n[addr] != NULL) {
+        return n[addr];
+    } else {
+        return r;
+    }
+}
+#endif
+
+
+static inline void ehci_set_interrupt(EHCIState *s, int intr)
+{
+    int level = 0;
+
+    // TODO honour interrupt threshold requests
+
+    s->usbsts |= intr;
+
+    if ((s->usbsts & USBINTR_MASK) & s->usbintr) {
+        level = 1;
+    }
+
+    qemu_set_irq(s->irq, level);
+}
+
+static inline void ehci_record_interrupt(EHCIState *s, int intr)
+{
+    s->usbsts_pending |= intr;
+}
+
+static inline void ehci_commit_interrupt(EHCIState *s)
+{
+    if (!s->usbsts_pending) {
+        return;
+    }
+    ehci_set_interrupt(s, s->usbsts_pending);
+    s->usbsts_pending = 0;
+}
+
+/* Attach or detach a device on root hub */
+
+static void ehci_attach(USBPort *port)
+{
+    EHCIState *s = port->opaque;
+    uint32_t *portsc = &s->portsc[port->index];
+
+    DPRINTF("ehci_attach invoked for index %d, portsc 0x%x, desc %s\n",
+           port->index, *portsc, port->dev->product_desc);
+
+    *portsc |= PORTSC_CONNECT;
+    *portsc |= PORTSC_CSC;
+
+    /*
+     *  If a high speed device is attached then we own this port(indicated
+     *  by zero in the PORTSC_POWNER bit field) so set the status bit
+     *  and set an interrupt if enabled.
+     */
+    if ( !(*portsc & PORTSC_POWNER)) {
+        ehci_set_interrupt(s, USBSTS_PCD);
+    }
+}
+
+static void ehci_detach(USBPort *port)
+{
+    EHCIState *s = port->opaque;
+    uint32_t *portsc = &s->portsc[port->index];
+
+    DPRINTF("ehci_attach invoked for index %d, portsc 0x%x\n",
+           port->index, *portsc);
+
+    *portsc &= ~PORTSC_CONNECT;
+    *portsc |= PORTSC_CSC;
+
+    /*
+     *  If a high speed device is attached then we own this port(indicated
+     *  by zero in the PORTSC_POWNER bit field) so set the status bit
+     *  and set an interrupt if enabled.
+     */
+    if ( !(*portsc & PORTSC_POWNER)) {
+        ehci_set_interrupt(s, USBSTS_PCD);
+    }
+}
+
+/* 4.1 host controller initialization */
+static void ehci_reset(void *opaque)
+{
+    EHCIState *s = opaque;
+    uint8_t *pci_conf;
+    int i;
+
+    pci_conf = s->dev.config;
+
+    memset(&s->mmio[OPREGBASE], 0x00, MMIO_SIZE - OPREGBASE);
+
+    s->usbcmd = NB_MAXINTRATE << USBCMD_ITC_SH;
+    s->usbsts = USBSTS_HALT;
+
+    s->astate = EST_INACTIVE;
+    s->pstate = EST_INACTIVE;
+    s->async_complete = 0;
+    s->isoch_pause = -1;
+    s->attach_poll_counter = 0;
+
+    for(i = 0; i < NB_PORTS; i++) {
+        s->portsc[i] = PORTSC_POWNER | PORTSC_PPOWER;
+
+        if (s->ports[i].dev) {
+            usb_attach(&s->ports[i], s->ports[i].dev);
+        }
+    }
+}
+
+static uint32_t ehci_mem_readb(void *ptr, target_phys_addr_t addr)
+{
+    EHCIState *s = ptr;
+    uint32_t val;
+
+    val = s->mmio[addr];
+
+    return val;
+}
+
+static uint32_t ehci_mem_readw(void *ptr, target_phys_addr_t addr)
+{
+    EHCIState *s = ptr;
+    uint32_t val;
+
+    val = s->mmio[addr] | (s->mmio[addr+1] << 8);
+
+    return val;
+}
+
+static uint32_t ehci_mem_readl(void *ptr, target_phys_addr_t addr)
+{
+    EHCIState *s = ptr;
+    uint32_t val;
+
+    val = s->mmio[addr] | (s->mmio[addr+1] << 8) |
+          (s->mmio[addr+2] << 16) | (s->mmio[addr+3] << 24);
+
+    return val;
+}
+
+static void ehci_mem_writeb(void *ptr, target_phys_addr_t addr, uint32_t val)
+{
+    fprintf(stderr, "EHCI doesn't handle byte writes to MMIO\n");
+    exit(1);
+}
+
+static void ehci_mem_writew(void *ptr, target_phys_addr_t addr, uint32_t val)
+{
+    fprintf(stderr, "EHCI doesn't handle 16-bit writes to MMIO\n");
+    exit(1);
+}
+
+static void handle_port_status_write(EHCIState *s, int port, uint32_t val)
+{
+    uint32_t *portsc = &s->portsc[port];
+    int rwc;
+    USBDevice *dev = s->ports[port].dev;
+
+    DPRINTF("port_status_write: "
+            "PORTSC (port %d) curr %08X new %08X rw-clear %08X rw %08X\n",
+            port, *portsc, val, (val & PORTSC_RWC_MASK), val & PORTSC_RO_MASK);
+
+    rwc = val & PORTSC_RWC_MASK;
+    val &= PORTSC_RO_MASK;
+
+    // handle_read_write_clear(&val, portsc, PORTSC_PEDC | PORTSC_CSC);
+
+    *portsc &= ~rwc;
+
+    if ((val & PORTSC_PRESET) && !(*portsc & PORTSC_PRESET)) {
+        DPRINTF("port_status_write: USBTRAN Port %d reset begin\n", port);
+    }
+
+    if (!(val & PORTSC_PRESET) &&(*portsc & PORTSC_PRESET)) {
+        DPRINTF("port_status_write: USBTRAN Port %d reset done\n", port);
+        usb_attach(&s->ports[port], dev);
+
+        // TODO how to handle reset of ports with no device
+        if (dev) {
+            usb_send_msg(dev, USB_MSG_RESET);
+        }
+
+        if (s->ports[port].dev) {
+            DPRINTF("port_status_write: "
+                    "Device was connected before reset, clearing CSC bit\n");
+            *portsc &= ~PORTSC_CSC;
+        }
+
+        /*  Table 2.16 Set the enable bit(and enable bit change) to indicate
+         *  to SW that this port has a high speed device attached
+         *
+         *  TODO - when to disable?
+         */
+        val |= PORTSC_PED;
+        val |= PORTSC_PEDC;
+    }
+
+    *portsc &= ~PORTSC_RO_MASK;
+    *portsc |= val;
+    DPRINTF("port_status_write: Port %d status set to 0x%08x\n", port, *portsc);
+}
+
+static void ehci_mem_writel(void *ptr, target_phys_addr_t addr, uint32_t val)
+{
+    EHCIState *s = ptr;
+    int i;
+#if EHCI_DEBUG
+    const char *str;
+#endif
+
+    /* Only aligned reads are allowed on OHCI */
+    if (addr & 3) {
+        fprintf(stderr, "usb-ehci: Mis-aligned write to addr 0x"
+                TARGET_FMT_plx "\n", addr);
+        return;
+    }
+
+    if (addr >= PORTSC && addr < PORTSC + 4 * NB_PORTS) {
+        handle_port_status_write(s, (addr-PORTSC)/4, val);
+        return;
+    }
+
+    if (addr < OPREGBASE) {
+        fprintf(stderr, "usb-ehci: write attempt to read-only register"
+                TARGET_FMT_plx "\n", addr);
+        return;
+    }
+
+
+    /* Do any register specific pre-write processing here.  */
+#if EHCI_DEBUG
+    str = addr2str((unsigned) addr);
+#endif
+    switch(addr) {
+    case USBCMD:
+        DPRINTF("ehci_mem_writel: USBCMD val=0x%08X, current cmd=0x%08X\n",
+                val, s->usbcmd);
+
+        if ((val & USBCMD_RUNSTOP) && !(s->usbcmd & USBCMD_RUNSTOP)) {
+            DPRINTF("ehci_mem_writel: %s run, clear halt\n", str);
+            qemu_mod_timer(s->frame_timer, qemu_get_clock_ns(vm_clock));
+            SET_LAST_RUN_CLOCK(s);
+            s->usbsts &= ~USBSTS_HALT;
+        }
+
+        if (!(val & USBCMD_RUNSTOP) && (s->usbcmd & USBCMD_RUNSTOP)) {
+            DPRINTF("                         ** STOP **\n");
+            qemu_del_timer(s->frame_timer);
+            // TODO - should finish out some stuff before setting halt
+            s->usbsts |= USBSTS_HALT;
+        }
+
+        if (val & USBCMD_HCRESET) {
+            DPRINTF("ehci_mem_writel: %s run, resetting\n", str);
+            ehci_reset(s);
+            val &= ~USBCMD_HCRESET;
+        }
+
+        /* not supporting dynamic frame list size at the moment */
+        if ((val & USBCMD_FLS) && !(s->usbcmd & USBCMD_FLS)) {
+            fprintf(stderr, "attempt to set frame list size -- value %d\n",
+                    val & USBCMD_FLS);
+            val &= ~USBCMD_FLS;
+        }
+#if EHCI_DEBUG
+        if ((val & USBCMD_PSE) && !(s->usbcmd & USBCMD_PSE)) {
+            DPRINTF("periodic scheduling enabled\n");
+        }
+        if (!(val & USBCMD_PSE) && (s->usbcmd & USBCMD_PSE)) {
+            DPRINTF("periodic scheduling disabled\n");
+        }
+        if ((val & USBCMD_ASE) && !(s->usbcmd & USBCMD_ASE)) {
+            DPRINTF("asynchronous scheduling enabled\n");
+        }
+        if (!(val & USBCMD_ASE) && (s->usbcmd & USBCMD_ASE)) {
+            DPRINTF("asynchronous scheduling disabled\n");
+        }
+        if ((val & USBCMD_IAAD) && !(s->usbcmd & USBCMD_IAAD)) {
+            DPRINTF("doorbell request received\n");
+        }
+        if ((val & USBCMD_LHCR) && !(s->usbcmd & USBCMD_LHCR)) {
+            DPRINTF("light host controller reset received\n");
+        }
+        if ((val & USBCMD_ITC) != (s->usbcmd & USBCMD_ITC)) {
+            DPRINTF("interrupt threshold control set to %x\n",
+                    (val & USBCMD_ITC)>>USBCMD_ITC_SH);
+        }
+#endif
+        break;
+
+
+    case USBSTS:
+        val &= USBSTS_RO_MASK;              // bits 6 thru 31 are RO
+        DPRINTF("ehci_mem_writel: %s RWC set to 0x%08X\n", str, val);
+
+        val = (s->usbsts &= ~val);         // bits 0 thru 5 are R/WC
+
+        DPRINTF("ehci_mem_writel: %s updating interrupt condition\n", str);
+        ehci_set_interrupt(s, 0);
+        break;
+
+
+    case USBINTR:
+        val &= USBINTR_MASK;
+        DPRINTF("ehci_mem_writel: %s set to 0x%08X\n", str, val);
+        break;
+
+    case FRINDEX:
+        s->sofv = val >> 3;
+        DPRINTF("ehci_mem_writel: %s set to 0x%08X\n", str, val);
+        break;
+
+    case CONFIGFLAG:
+        DPRINTF("ehci_mem_writel: %s set to 0x%08X\n", str, val);
+        val &= 0x1;
+        if (val) {
+            for(i = 0; i < NB_PORTS; i++)
+                s->portsc[i] &= ~PORTSC_POWNER;
+        }
+        break;
+
+    case PERIODICLISTBASE:
+        if ((s->usbcmd & USBCMD_PSE) && (s->usbcmd & USBCMD_RUNSTOP)) {
+            fprintf(stderr,
+              "ehci: PERIODIC list base register set while periodic schedule\n"
+              "      is enabled and HC is enabled\n");
+        }
+        DPRINTF("ehci_mem_writel: P-LIST BASE set to 0x%08X\n", val);
+        break;
+
+    case ASYNCLISTADDR:
+        if ((s->usbcmd & USBCMD_ASE) && (s->usbcmd & USBCMD_RUNSTOP)) {
+            fprintf(stderr,
+              "ehci: ASYNC list address register set while async schedule\n"
+              "      is enabled and HC is enabled\n");
+        }
+        DPRINTF("ehci_mem_writel: A-LIST ADDR set to 0x%08X\n", val);
+        break;
+    }
+
+    *(uint32_t *)(&s->mmio[addr]) = val;
+}
+
+
+// TODO : Put in common header file, duplication from usb-ohci.c
+
+/* Get an array of dwords from main memory */
+static inline int get_dwords(uint32_t addr, uint32_t *buf, int num)
+{
+    int i;
+
+    for(i = 0; i < num; i++, buf++, addr += sizeof(*buf)) {
+        cpu_physical_memory_rw(addr,(uint8_t *)buf, sizeof(*buf), 0);
+        *buf = le32_to_cpu(*buf);
+    }
+
+    return 1;
+}
+
+/* Put an array of dwords in to main memory */
+static inline int put_dwords(uint32_t addr, uint32_t *buf, int num)
+{
+    int i;
+
+    for(i = 0; i < num; i++, buf++, addr += sizeof(*buf)) {
+        uint32_t tmp = cpu_to_le32(*buf);
+        cpu_physical_memory_rw(addr,(uint8_t *)&tmp, sizeof(tmp), 1);
+    }
+
+    return 1;
+}
+
+// 4.10.2
+
+static int ehci_qh_do_overlay(EHCIState *ehci, EHCIqh *qh, EHCIqtd *qtd)
+{
+    int i;
+    int dtoggle;
+    int ping;
+    int eps;
+    int reload;
+
+    // remember values in fields to preserve in qh after overlay
+
+    dtoggle = qh->token & QTD_TOKEN_DTOGGLE;
+    ping    = qh->token & QTD_TOKEN_PING;
+
+    DPRINTF("setting qh.current from %08X to 0x%08X\n", qh->current_qtd,
+            ehci->qtdaddr);
+    qh->current_qtd = ehci->qtdaddr;
+    qh->next_qtd    = qtd->next;
+    qh->altnext_qtd = qtd->altnext;
+    qh->token       = qtd->token;
+
+
+    eps = get_field(qh->epchar, QH_EPCHAR_EPS);
+    if (eps == EHCI_QH_EPS_HIGH) {
+        qh->token &= ~QTD_TOKEN_PING;
+        qh->token |= ping;
+    }
+
+    reload = get_field(qh->epchar, QH_EPCHAR_RL);
+    set_field(&qh->altnext_qtd, reload, QH_ALTNEXT_NAKCNT);
+
+    for (i = 0; i < 5; i++) {
+        qh->bufptr[i] = qtd->bufptr[i];
+    }
+
+    if (!(qh->epchar & QH_EPCHAR_DTC)) {
+        // preserve QH DT bit
+        qh->token &= ~QTD_TOKEN_DTOGGLE;
+        qh->token |= dtoggle;
+    }
+
+    qh->bufptr[1] &= ~BUFPTR_CPROGMASK_MASK;
+    qh->bufptr[2] &= ~BUFPTR_FRAMETAG_MASK;
+
+    put_dwords(NLPTR_GET(ehci->qhaddr), (uint32_t *) qh, sizeof(EHCIqh) >> 2);
+
+    return 0;
+}
+
+static int ehci_buffer_rw(uint8_t *buffer, EHCIqh *qh, int bytes, int rw)
+{
+    int bufpos = 0;
+    int cpage, offset;
+    uint32_t head;
+    uint32_t tail;
+
+
+    if (!bytes) {
+        return 0;
+    }
+
+    cpage = get_field(qh->token, QTD_TOKEN_CPAGE);
+    if (cpage > 4) {
+        fprintf(stderr, "cpage out of range (%d)\n", cpage);
+        return USB_RET_PROCERR;
+    }
+
+    offset = qh->bufptr[0] & ~QTD_BUFPTR_MASK;
+    DPRINTF("ehci_buffer_rw: %sing %d bytes %08x cpage %d offset %d\n",
+           rw ? "writ" : "read", bytes, qh->bufptr[0], cpage, offset);
+
+    do {
+        /* start and end of this page */
+        head = qh->bufptr[cpage] & QTD_BUFPTR_MASK;
+        tail = head + ~QTD_BUFPTR_MASK + 1;
+        /* add offset into page */
+        head |= offset;
+
+        if (bytes <= (tail - head)) {
+            tail = head + bytes;
+        }
+
+        DPRINTF("DATA %s cpage:%d head:%08X tail:%08X target:%08X\n",
+                rw ? "WRITE" : "READ ", cpage, head, tail, bufpos);
+
+        cpu_physical_memory_rw(head, &buffer[bufpos], tail - head, rw);
+
+        bufpos += (tail - head);
+        bytes -= (tail - head);
+
+        if (bytes > 0) {
+            cpage++;
+            offset = 0;
+        }
+    } while (bytes > 0);
+
+    /* save cpage */
+    set_field(&qh->token, cpage, QTD_TOKEN_CPAGE);
+
+    /* save offset into cpage */
+    offset = tail - head;
+    qh->bufptr[0] &= ~QTD_BUFPTR_MASK;
+    qh->bufptr[0] |= offset;
+
+    return 0;
+}
+
+static void ehci_async_complete_packet(USBDevice *dev, USBPacket *packet)
+{
+    EHCIState *ehci = container_of(packet, EHCIState, usb_packet);
+
+    DPRINTF("Async packet complete\n");
+    ehci->async_complete = 1;
+    ehci->exec_status = packet->len;
+}
+
+static int ehci_execute_complete(EHCIState *ehci, EHCIqh *qh, int ret)
+{
+    int c_err, reload;
+
+    if (ret == USB_RET_ASYNC && !ehci->async_complete) {
+        DPRINTF("not done yet\n");
+        return ret;
+    }
+
+    ehci->async_complete = 0;
+
+    DPRINTF("execute_complete: qhaddr 0x%x, next %x, qtdaddr 0x%x, status %d\n",
+            ehci->qhaddr, qh->next, ehci->qtdaddr, ret);
+
+    if (ret < 0) {
+err:
+        /* TO-DO: put this is in a function that can be invoked below as well */
+        c_err = get_field(qh->token, QTD_TOKEN_CERR);
+        c_err--;
+        set_field(&qh->token, c_err, QTD_TOKEN_CERR);
+
+        switch(ret) {
+        case USB_RET_NODEV:
+            fprintf(stderr, "USB no device\n");
+            break;
+        case USB_RET_STALL:
+            fprintf(stderr, "USB stall\n");
+            qh->token |= QTD_TOKEN_HALT;
+            ehci_record_interrupt(ehci, USBSTS_ERRINT);
+            break;
+        case USB_RET_NAK:
+            /* 4.10.3 */
+            reload = get_field(qh->epchar, QH_EPCHAR_RL);
+            if ((ehci->pid == USB_TOKEN_IN) && reload) {
+                int nakcnt = get_field(qh->altnext_qtd, QH_ALTNEXT_NAKCNT);
+                nakcnt--;
+                set_field(&qh->altnext_qtd, nakcnt, QH_ALTNEXT_NAKCNT);
+            } else if (!reload) {
+                return USB_RET_NAK;
+            }
+            break;
+        case USB_RET_BABBLE:
+            fprintf(stderr, "USB babble TODO\n");
+            qh->token |= QTD_TOKEN_BABBLE;
+            ehci_record_interrupt(ehci, USBSTS_ERRINT);
+            break;
+        default:
+            fprintf(stderr, "USB invalid response %d to handle\n", ret);
+            /* TO-DO: transaction error */
+            ret = USB_RET_PROCERR;
+            break;
+        }
+    } else {
+        // DPRINTF("Short packet condition\n");
+        // TODO check 4.12 for splits
+
+        if ((ret > ehci->tbytes) && (ehci->pid == USB_TOKEN_IN)) {
+            ret = USB_RET_BABBLE;
+            goto err;
+        }
+
+        if (ehci->tbytes && ehci->pid == USB_TOKEN_IN) {
+            if (ehci_buffer_rw(ehci->buffer, qh, ret, 1) != 0) {
+                return USB_RET_PROCERR;
+            }
+            ehci->tbytes -= ret;
+        } else {
+            ehci->tbytes = 0;
+        }
+
+        DPRINTF("updating tbytes to %d\n", ehci->tbytes);
+        set_field(&qh->token, ehci->tbytes, QTD_TOKEN_TBYTES);
+    }
+
+    qh->token ^= QTD_TOKEN_DTOGGLE;
+    qh->token &= ~QTD_TOKEN_ACTIVE;
+
+    if ((ret >= 0) && (qh->token & QTD_TOKEN_IOC)) {
+        ehci_record_interrupt(ehci, USBSTS_INT);
+    }
+
+    return ret;
+}
+
+// 4.10.3
+
+static int ehci_execute(EHCIState *ehci, EHCIqh *qh)
+{
+    USBPort *port;
+    USBDevice *dev;
+    int ret;
+    int i;
+    int endp;
+    int devadr;
+
+    if ( !(qh->token & QTD_TOKEN_ACTIVE)) {
+        fprintf(stderr, "Attempting to execute inactive QH\n");
+        return USB_RET_PROCERR;
+    }
+
+    ehci->tbytes = (qh->token & QTD_TOKEN_TBYTES_MASK) >> QTD_TOKEN_TBYTES_SH;
+    if (ehci->tbytes > BUFF_SIZE) {
+        fprintf(stderr, "Request for more bytes than allowed\n");
+        return USB_RET_PROCERR;
+    }
+
+    ehci->pid = (qh->token & QTD_TOKEN_PID_MASK) >> QTD_TOKEN_PID_SH;
+    switch(ehci->pid) {
+        case 0: ehci->pid = USB_TOKEN_OUT; break;
+        case 1: ehci->pid = USB_TOKEN_IN; break;
+        case 2: ehci->pid = USB_TOKEN_SETUP; break;
+        default: fprintf(stderr, "bad token\n"); break;
+    }
+
+    if ((ehci->tbytes && ehci->pid != USB_TOKEN_IN) &&
+        (ehci_buffer_rw(ehci->buffer, qh, ehci->tbytes, 0) != 0)) {
+        return USB_RET_PROCERR;
+    }
+
+    endp = get_field(qh->epchar, QH_EPCHAR_EP);
+    devadr = get_field(qh->epchar, QH_EPCHAR_DEVADDR);
+
+    ret = USB_RET_NODEV;
+
+    // TO-DO: associating device with ehci port
+    for(i = 0; i < NB_PORTS; i++) {
+        port = &ehci->ports[i];
+        dev = port->dev;
+
+        // TODO sometime we will also need to check if we are the port owner
+
+        if (!(ehci->portsc[i] &(PORTSC_CONNECT))) {
+            DPRINTF("Port %d, no exec, not connected(%08X)\n",
+                    i, ehci->portsc[i]);
+            continue;
+        }
+
+        ehci->usb_packet.pid = ehci->pid;
+        ehci->usb_packet.devaddr = devadr;
+        ehci->usb_packet.devep = endp;
+        ehci->usb_packet.data = ehci->buffer;
+        ehci->usb_packet.len = ehci->tbytes;
+
+        ret = usb_handle_packet(dev, &ehci->usb_packet);
+
+        DPRINTF("submit: qh %x next %x qtd %x pid %x len %d (total %d) endp %x ret %d\n",
+                ehci->qhaddr, qh->next, ehci->qtdaddr, ehci->pid,
+                ehci->usb_packet.len, ehci->tbytes, endp, ret);
+
+        if (ret != USB_RET_NODEV) {
+            break;
+        }
+    }
+
+    if (ret > BUFF_SIZE) {
+        fprintf(stderr, "ret from usb_handle_packet > BUFF_SIZE\n");
+        return USB_RET_PROCERR;
+    }
+
+    if (ret == USB_RET_ASYNC) {
+        ehci->async_complete = 0;
+    }
+
+    return ret;
+}
+
+/*  4.7.2
+ */
+
+static int ehci_process_itd(EHCIState *ehci,
+                            EHCIitd *itd)
+{
+    USBPort *port;
+    USBDevice *dev;
+    int ret;
+    int i, j;
+    int ptr;
+    int pid;
+    int pg;
+    int len;
+    int dir;
+    int devadr;
+    int endp;
+    int maxpkt;
+
+    dir =(itd->bufptr[1] & ITD_BUFPTR_DIRECTION);
+    devadr = get_field(itd->bufptr[0], ITD_BUFPTR_DEVADDR);
+    endp = get_field(itd->bufptr[0], ITD_BUFPTR_EP);
+    maxpkt = get_field(itd->bufptr[1], ITD_BUFPTR_MAXPKT);
+
+    for(i = 0; i < 8; i++) {
+        if (itd->transact[i] & ITD_XACT_ACTIVE) {
+            DPRINTF("ISOCHRONOUS active for frame %d, interval %d\n",
+                    ehci->frindex >> 3, i);
+
+            pg = get_field(itd->transact[i], ITD_XACT_PGSEL);
+            ptr = (itd->bufptr[pg] & ITD_BUFPTR_MASK) |
+                (itd->transact[i] & ITD_XACT_OFFSET_MASK);
+            len = get_field(itd->transact[i], ITD_XACT_LENGTH);
+
+            if (len > BUFF_SIZE) {
+                return USB_RET_PROCERR;
+            }
+
+            DPRINTF("ISOCH: buffer %08X len %d\n", ptr, len);
+
+            if (!dir) {
+                cpu_physical_memory_rw(ptr, &ehci->buffer[0], len, 0);
+                pid = USB_TOKEN_OUT;
+            } else
+                pid = USB_TOKEN_IN;
+
+            ret = USB_RET_NODEV;
+
+            for (j = 0; j < NB_PORTS; j++) {
+                port = &ehci->ports[j];
+                dev = port->dev;
+
+                // TODO sometime we will also need to check if we are the port owner
+
+                if (!(ehci->portsc[j] &(PORTSC_CONNECT))) {
+                    DPRINTF("Port %d, no exec, not connected(%08X)\n",
+                            j, ehci->portsc[j]);
+                    continue;
+                }
+
+                ehci->usb_packet.pid = ehci->pid;
+                ehci->usb_packet.devaddr = devadr;
+                ehci->usb_packet.devep = endp;
+                ehci->usb_packet.data = ehci->buffer;
+                ehci->usb_packet.len = len;
+
+                DPRINTF("calling usb_handle_packet\n");
+                ret = usb_handle_packet(dev, &ehci->usb_packet);
+
+                if (ret != USB_RET_NODEV) {
+                    break;
+                }
+            }
+
+            /*  In isoch, there is no facility to indicate a NAK so let's
+             *  instead just complete a zero-byte transaction.  Setting
+             *  DBERR seems too draconian.
+             */
+
+            if (ret == USB_RET_NAK) {
+                if (ehci->isoch_pause > 0) {
+                    DPRINTF("ISOCH: received a NAK but paused so returning\n");
+                    ehci->isoch_pause--;
+                    return 0;
+                } else if (ehci->isoch_pause == -1) {
+                    DPRINTF("ISOCH: recv NAK & isoch pause inactive, setting\n");
+                    // Pause frindex for up to 50 msec waiting for data from
+                    // remote
+                    ehci->isoch_pause = 50;
+                    return 0;
+                } else {
+                    DPRINTF("ISOCH: isoch pause timeout! return 0\n");
+                    ret = 0;
+                }
+            } else {
+                DPRINTF("ISOCH: received ACK, clearing pause\n");
+                ehci->isoch_pause = -1;
+            }
+
+            if (ret >= 0) {
+                itd->transact[i] &= ~ITD_XACT_ACTIVE;
+
+                if (itd->transact[i] & ITD_XACT_IOC) {
+                    ehci_record_interrupt(ehci, USBSTS_INT);
+                }
+            }
+
+            if (ret >= 0 && dir) {
+                cpu_physical_memory_rw(ptr, &ehci->buffer[0], len, 1);
+
+                if (ret != len) {
+                    DPRINTF("ISOCH IN expected %d, got %d\n",
+                            len, ret);
+                    set_field(&itd->transact[i], ret, ITD_XACT_LENGTH);
+                }
+            }
+        }
+    }
+    return 0;
+}
+
+/*  This state is the entry point for asynchronous schedule
+ *  processing.  Entry here consitutes a EHCI start event state (4.8.5)
+ */
+static int ehci_state_waitlisthead(EHCIState *ehci,  int async, int *state)
+{
+    EHCIqh *qh = &ehci->qh;
+    int i = 0;
+    int again = 0;
+    uint32_t entry = ehci->asynclistaddr;
+
+    /* set reclamation flag at start event (4.8.6) */
+    if (async) {
+        ehci->usbsts |= USBSTS_REC;
+    }
+
+    /*  Find the head of the list (4.9.1.1) */
+    for(i = 0; i < MAX_QH; i++) {
+        get_dwords(NLPTR_GET(entry), (uint32_t *) qh, sizeof(EHCIqh) >> 2);
+
+        if (qh->epchar & QH_EPCHAR_H) {
+            DPRINTF_ST("WAITLISTHEAD: QH %08X is the HEAD of the list\n",
+                       entry);
+            if (async) {
+                entry |= (NLPTR_TYPE_QH << 1);
+            }
+
+            ehci->fetch_addr = entry;
+            *state = EST_FETCHENTRY;
+            again = 1;
+            goto out;
+        }
+
+        DPRINTF_ST("WAITLISTHEAD: QH %08X is NOT the HEAD of the list\n",
+                   entry);
+        entry = qh->next;
+        if (entry == ehci->asynclistaddr) {
+            DPRINTF("WAITLISTHEAD: reached beginning of QH list\n");
+            break;
+        }
+    }
+
+    /* no head found for list. */
+
+    *state = EST_ACTIVE;
+
+out:
+    return again;
+}
+
+
+/*  This state is the entry point for periodic schedule processing as
+ *  well as being a continuation state for async processing.
+ */
+static int ehci_state_fetchentry(EHCIState *ehci, int async, int *state)
+{
+    int again = 0;
+    uint32_t entry = ehci->fetch_addr;
+
+#if EHCI_DEBUG == 0
+    if (qemu_get_clock_ns(vm_clock) / 1000 >= ehci->frame_end_usec) {
+        if (async) {
+            DPRINTF("FETCHENTRY: FRAME timer elapsed, exit state machine\n");
+            goto out;
+        } else {
+            DPRINTF("FETCHENTRY: WARNING "
+                    "- frame timer elapsed during periodic\n");
+        }
+    }
+#endif
+    if (entry < 0x1000) {
+        DPRINTF("fetchentry: entry invalid (0x%08x)\n", entry);
+        *state = EST_ACTIVE;
+        goto out;
+    }
+
+    /* section 4.8, only QH in async schedule */
+    if (async && (NLPTR_TYPE_GET(entry) != NLPTR_TYPE_QH)) {
+        fprintf(stderr, "non queue head request in async schedule\n");
+        return -1;
+    }
+
+    switch (NLPTR_TYPE_GET(entry)) {
+    case NLPTR_TYPE_QH:
+        DPRINTF_ST("FETCHENTRY: entry %X is a Queue Head\n", entry);
+        *state = EST_FETCHQH;
+        ehci->qhaddr = entry;
+        again = 1;
+        break;
+
+    case NLPTR_TYPE_ITD:
+        DPRINTF_ST("FETCHENTRY: entry %X is an ITD\n", entry);
+        *state = EST_FETCHITD;
+        ehci->itdaddr = entry;
+        again = 1;
+        break;
+
+    default:
+        // TODO: handle siTD and FSTN types
+        fprintf(stderr, "FETCHENTRY: entry at %X is of type %d "
+                "which is not supported yet\n", entry, NLPTR_TYPE_GET(entry));
+        return -1;
+    }
+
+out:
+    return again;
+}
+
+static int ehci_state_fetchqh(EHCIState *ehci, int async, int *state)
+{
+    EHCIqh *qh = &ehci->qh;
+    int reload;
+    int again = 0;
+
+    get_dwords(NLPTR_GET(ehci->qhaddr), (uint32_t *) qh, sizeof(EHCIqh) >> 2);
+
+    if (async && (qh->epchar & QH_EPCHAR_H)) {
+
+        /*  EHCI spec version 1.0 Section 4.8.3 & 4.10.1 */
+        if (ehci->usbsts & USBSTS_REC) {
+            ehci->usbsts &= ~USBSTS_REC;
+        } else {
+            DPRINTF("FETCHQH:  QH 0x%08x. H-bit set, reclamation status reset"
+                       " - done processing\n", ehci->qhaddr);
+            *state = EST_ACTIVE;
+            goto out;
+        }
+    }
+
+#if EHCI_DEBUG
+    if (ehci->qhaddr != qh->next) {
+    DPRINTF("FETCHQH:  QH 0x%08x (h %x halt %x active %x) next 0x%08x\n",
+               ehci->qhaddr,
+               qh->epchar & QH_EPCHAR_H,
+               qh->token & QTD_TOKEN_HALT,
+               qh->token & QTD_TOKEN_ACTIVE,
+               qh->next);
+    }
+#endif
+
+    reload = get_field(qh->epchar, QH_EPCHAR_RL);
+    if (reload) {
+        DPRINTF_ST("FETCHQH: reloading nakcnt to %d\n", reload);
+        set_field(&qh->altnext_qtd, reload, QH_ALTNEXT_NAKCNT);
+    }
+
+    if (qh->token & QTD_TOKEN_HALT) {
+        DPRINTF_ST("FETCHQH: QH Halted, go horizontal\n");
+        *state = EST_HORIZONTALQH;
+        again = 1;
+
+    } else if ((qh->token & QTD_TOKEN_ACTIVE) && (qh->current_qtd > 0x1000)) {
+        DPRINTF_ST("FETCHQH: Active, !Halt, execute - fetch qTD\n");
+        ehci->qtdaddr = qh->current_qtd;
+        *state = EST_FETCHQTD;
+        again = 1;
+
+    } else {
+        /*  EHCI spec version 1.0 Section 4.10.2 */
+        DPRINTF_ST("FETCHQH: !Active, !Halt, advance queue\n");
+        *state = EST_ADVANCEQUEUE;
+        again = 1;
+    }
+
+out:
+    return again;
+}
+
+static int ehci_state_fetchitd(EHCIState *ehci, int async, int *state)
+{
+    EHCIitd itd;
+
+    get_dwords(NLPTR_GET(ehci->itdaddr),(uint32_t *) &itd,
+               sizeof(EHCIitd) >> 2);
+    DPRINTF_ST("FETCHITD: Fetched ITD at address %08X " "(next is %08X)\n",
+               ehci->itdaddr, itd.next);
+
+    if (ehci_process_itd(ehci, &itd) != 0) {
+        return -1;
+    }
+
+    put_dwords(NLPTR_GET(ehci->itdaddr), (uint32_t *) &itd,
+                sizeof(EHCIitd) >> 2);
+    ehci->fetch_addr = itd.next;
+    *state = EST_FETCHENTRY;
+
+    return 1;
+}
+
+/* Section 4.10.2 - paragraph 3 */
+static int ehci_state_advqueue(EHCIState *ehci, int async, int *state)
+{
+#if 0
+    /* TO-DO: 4.10.2 - paragraph 2
+     * if I-bit is set to 1 and QH is not active
+     * go to horizontal QH
+     */
+    if (I-bit set) {
+        *state = EST_HORIZONTALQH;
+        goto out;
+    }
+#endif
+
+    /*
+     * want data and alt-next qTD is valid
+     */
+    if (((ehci->qh.token & QTD_TOKEN_TBYTES_MASK) != 0) &&
+        (ehci->qh.altnext_qtd > 0x1000) &&
+        (NLPTR_TBIT(ehci->qh.altnext_qtd) == 0)) {
+        DPRINTF_ST("ADVQUEUE: goto alt next qTD. "
+                   "curr 0x%08x next 0x%08x alt 0x%08x (next qh %x)\n",
+                   ehci->qh.current_qtd, ehci->qh.altnext_qtd,
+                   ehci->qh.next_qtd, ehci->qh.next);
+        ehci->qtdaddr = ehci->qh.altnext_qtd;
+        *state = EST_FETCHQTD;
+
+    /*
+     *  next qTD is valid
+     */
+    } else if ((ehci->qh.next_qtd > 0x1000) &&
+               (NLPTR_TBIT(ehci->qh.next_qtd) == 0)) {
+        DPRINTF_ST("ADVQUEUE: next qTD. "
+                   "curr 0x%08x next 0x%08x alt 0x%08x (next qh %x)\n",
+                   ehci->qh.current_qtd, ehci->qh.altnext_qtd,
+                   ehci->qh.next_qtd, ehci->qh.next);
+        ehci->qtdaddr = ehci->qh.next_qtd;
+        *state = EST_FETCHQTD;
+
+    /*
+     *  no valid qTD, try next QH
+     */
+    } else {
+        DPRINTF_ST("ADVQUEUE: go to horizontal QH\n");
+        *state = EST_HORIZONTALQH;
+    }
+
+    return 1;
+}
+
+/* Section 4.10.2 - paragraph 4 */
+static int ehci_state_fetchqtd(EHCIState *ehci, int async, int *state)
+{
+    EHCIqtd *qtd = &ehci->qtd;
+    int again = 0;
+
+    get_dwords(NLPTR_GET(ehci->qtdaddr),(uint32_t *) qtd, sizeof(EHCIqtd) >> 2);
+
+    if (qtd->token & QTD_TOKEN_ACTIVE) {
+        *state = EST_EXECUTE;
+        again = 1;
+    } else {
+        *state = EST_HORIZONTALQH;
+        again = 1;
+    }
+
+    return again;
+}
+
+static int ehci_state_horizqh(EHCIState *ehci, int async, int *state)
+{
+    int again = 0;
+
+    if (ehci->fetch_addr != ehci->qh.next) {
+        ehci->fetch_addr = ehci->qh.next;
+        *state = EST_FETCHENTRY;
+        again = 1;
+    } else {
+        *state = EST_ACTIVE;
+    }
+
+    return again;
+}
+
+static int ehci_state_execute(EHCIState *ehci, int async, int *state)
+{
+    EHCIqh *qh = &ehci->qh;
+    EHCIqtd *qtd = &ehci->qtd;
+    int again = 0;
+    int reload, nakcnt;
+    int smask;
+
+    if (async) {
+        DPRINTF_ST(">>>>> ASYNC STATE MACHINE execute QH 0x%08x, QTD 0x%08x\n",
+                  ehci->qhaddr, ehci->qtdaddr);
+    } else {
+        DPRINTF_ST(">>>>> PERIODIC STATE MACHINE execute\n");
+    }
+
+    if (ehci_qh_do_overlay(ehci, qh, qtd) != 0) {
+        return -1;
+    }
+
+    smask = get_field(qh->epcap, QH_EPCAP_SMASK);
+
+    if (!smask) {
+        reload = get_field(qh->epchar, QH_EPCHAR_RL);
+        nakcnt = get_field(qh->altnext_qtd, QH_ALTNEXT_NAKCNT);
+        if (reload && !nakcnt) {
+            DPRINTF_ST("EXECUTE: RL != 0 but NakCnt == 0 -- no execute\n");
+            *state = EST_HORIZONTALQH;
+            again = 1;
+            goto out;
+        }
+    }
+
+    // TODO verify enough time remains in the uframe as in 4.4.1.1
+    // TODO write back ptr to async list when done or out of time
+    // TODO Windows does not seem to ever set the MULT field
+
+    if (!async) {
+        int transactCtr = get_field(qh->epcap, QH_EPCAP_MULT);
+        if (!transactCtr) {
+            DPRINTF("ZERO transactctr for int qh, go HORIZ\n");
+            *state = EST_HORIZONTALQH;
+            again = 1;
+            goto out;
+        }
+    }
+
+    if (async) {
+        ehci->usbsts |= USBSTS_REC;
+    }
+
+    ehci->exec_status = ehci_execute(ehci, qh);
+    if (ehci->exec_status == USB_RET_PROCERR) {
+        again = -1;
+        goto out;
+    }
+    *state = EST_EXECUTING;
+
+    if (ehci->exec_status != USB_RET_ASYNC) {
+        again = 1;
+    }
+
+out:
+    return again;
+}
+
+static int ehci_state_executing(EHCIState *ehci, int async, int *state)
+{
+    EHCIqh *qh = &ehci->qh;
+    int again = 0;
+    int reload, nakcnt;
+
+    ehci->exec_status = ehci_execute_complete(ehci, qh, ehci->exec_status);
+    if (ehci->exec_status == USB_RET_ASYNC) {
+        goto out;
+    }
+    if (ehci->exec_status == USB_RET_PROCERR) {
+        again = -1;
+        goto out;
+    }
+
+    // 4.10.3
+    if (!async) {
+        int transactCtr = get_field(qh->epcap, QH_EPCAP_MULT);
+        transactCtr--;
+        set_field(&qh->epcap, transactCtr, QH_EPCAP_MULT);
+        // 4.10.3, bottom of page 82, should exit this state when transaction
+        // counter decrements to 0
+    }
+
+
+    reload = get_field(qh->epchar, QH_EPCHAR_RL);
+    if (reload) {
+        nakcnt = get_field(qh->altnext_qtd, QH_ALTNEXT_NAKCNT);
+        if (ehci->exec_status == USB_RET_NAK) {
+            if (nakcnt) {
+                nakcnt--;
+            }
+            DPRINTF_ST("EXECUTING: Nak occured and RL != 0, dec NakCnt to %d\n",
+                    nakcnt);
+        } else {
+            nakcnt = reload;
+            DPRINTF_ST("EXECUTING: Nak didn't occur, reloading to %d\n",
+                       nakcnt);
+        }
+        set_field(&qh->altnext_qtd, nakcnt, QH_ALTNEXT_NAKCNT);
+    }
+
+    /*
+     *  Write the qh back to guest physical memory.  This step isn't
+     *  in the EHCI spec but we need to do it since we don't share
+     *  physical memory with our guest VM.
+     */
+
+    DPRINTF("EXECUTING: write QH to VM memory: qhaddr 0x%x, next 0x%x\n",
+              ehci->qhaddr, qh->next);
+    put_dwords(NLPTR_GET(ehci->qhaddr), (uint32_t *) qh, sizeof(EHCIqh) >> 2);
+
+    /* 4.10.5 */
+    if ((ehci->exec_status == USB_RET_NAK) || (qh->token & QTD_TOKEN_ACTIVE)) {
+        *state = EST_HORIZONTALQH;
+    } else {
+        *state = EST_WRITEBACK;
+    }
+
+    again = 1;
+
+out:
+    return again;
+}
+
+
+static int ehci_state_writeback(EHCIState *ehci, int async, int *state)
+{
+    EHCIqh *qh = &ehci->qh;
+    int again = 0;
+
+    /*  Write back the QTD from the QH area */
+    DPRINTF_ST("WRITEBACK: write QTD to VM memory\n");
+    put_dwords(NLPTR_GET(ehci->qtdaddr),(uint32_t *) &qh->next_qtd,
+                sizeof(EHCIqtd) >> 2);
+
+    /* TODO confirm next state.  For now, keep going if async
+     * but stop after one qtd if periodic
+     */
+    //if (async) {
+        *state = EST_ADVANCEQUEUE;
+        again = 1;
+    //} else {
+    //    *state = EST_ACTIVE;
+    //}
+    return again;
+}
+
+/*
+ * This is the state machine that is common to both async and periodic
+ */
+
+static int ehci_advance_state(EHCIState *ehci,
+                              int async,
+                              int state)
+{
+    int again;
+    int iter = 0;
+
+    do {
+        if (state == EST_FETCHQH) {
+            iter++;
+            /* if we are roaming a lot of QH without executing a qTD
+             * something is wrong with the linked list. TO-DO: why is
+             * this hack needed?
+             */
+            if (iter > MAX_ITERATIONS) {
+                DPRINTF("\n*** advance_state: bailing on MAX ITERATIONS***\n");
+                state = EST_ACTIVE;
+                break;
+            }
+        }
+        switch(state) {
+        case EST_WAITLISTHEAD:
+            again = ehci_state_waitlisthead(ehci, async, &state);
+            break;
+
+        case EST_FETCHENTRY:
+            again = ehci_state_fetchentry(ehci, async, &state);
+            break;
+
+        case EST_FETCHQH:
+            again = ehci_state_fetchqh(ehci, async, &state);
+            break;
+
+        case EST_FETCHITD:
+            again = ehci_state_fetchitd(ehci, async, &state);
+            break;
+
+        case EST_ADVANCEQUEUE:
+            again = ehci_state_advqueue(ehci, async, &state);
+            break;
+
+        case EST_FETCHQTD:
+            again = ehci_state_fetchqtd(ehci, async, &state);
+            break;
+
+        case EST_HORIZONTALQH:
+            again = ehci_state_horizqh(ehci, async, &state);
+            break;
+
+        case EST_EXECUTE:
+            iter = 0;
+            again = ehci_state_execute(ehci, async, &state);
+            break;
+
+        case EST_EXECUTING:
+            again = ehci_state_executing(ehci, async, &state);
+            break;
+
+        case EST_WRITEBACK:
+            again = ehci_state_writeback(ehci, async, &state);
+            break;
+
+        default:
+            fprintf(stderr, "Bad state!\n");
+            again = -1;
+            break;
+        }
+
+        if (again < 0) {
+            fprintf(stderr, "processing error - resetting ehci HC\n");
+            ehci_reset(ehci);
+            again = 0;
+        }
+    }
+    while (again);
+
+    ehci_commit_interrupt(ehci);
+    return state;
+}
+
+static void ehci_advance_async_state(EHCIState *ehci)
+{
+    EHCIqh qh;
+    int state = ehci->astate;
+
+    switch(state) {
+    case EST_INACTIVE:
+        if (!(ehci->usbcmd & USBCMD_ASE)) {
+            break;
+        }
+        ehci->usbsts |= USBSTS_ASS;
+        ehci->astate = EST_ACTIVE;
+        // No break, fall through to ACTIVE
+
+    case EST_ACTIVE:
+        if ( !(ehci->usbcmd & USBCMD_ASE)) {
+            ehci->usbsts &= ~USBSTS_ASS;
+            ehci->astate = EST_INACTIVE;
+            break;
+        }
+
+        /* If the doorbell is set, the guest wants to make a change to the
+         * schedule. The host controller needs to release cached data.
+         * (section 4.8.2)
+         */
+        if (ehci->usbcmd & USBCMD_IAAD) {
+            DPRINTF("ASYNC: doorbell request acknowledged\n");
+            ehci->usbcmd &= ~USBCMD_IAAD;
+            ehci_set_interrupt(ehci, USBSTS_IAA);
+            break;
+        }
+
+        /* make sure guest has acknowledged */
+        /* TO-DO: is this really needed? */
+        if (ehci->usbsts & USBSTS_IAA) {
+            DPRINTF("IAA status bit still set.\n");
+            break;
+        }
+
+        DPRINTF_ST("ASYNC: waiting for listhead, starting at %08x\n",
+                ehci->asynclistaddr);
+        /* check that address register has been set */
+        if (ehci->asynclistaddr == 0) {
+            break;
+        }
+
+        state = EST_WAITLISTHEAD;
+        /* fall through */
+
+    case EST_FETCHENTRY:
+        /* fall through */
+
+    case EST_EXECUTING:
+        get_dwords(NLPTR_GET(ehci->qhaddr), (uint32_t *) &qh,
+                   sizeof(EHCIqh) >> 2);
+        ehci->astate = ehci_advance_state(ehci, 1, state);
+        break;
+
+    default:
+        /* this should only be due to a developer mistake */
+        fprintf(stderr, "ehci: Bad asynchronous state %d. "
+                "Resetting to active\n", ehci->astate);
+        ehci->astate = EST_ACTIVE;
+    }
+}
+
+static void ehci_advance_periodic_state(EHCIState *ehci)
+{
+    uint32_t entry;
+    uint32_t list;
+
+    // 4.6
+
+    switch(ehci->pstate) {
+    case EST_INACTIVE:
+        if ( !(ehci->frindex & 7) && (ehci->usbcmd & USBCMD_PSE)) {
+            DPRINTF("PERIODIC going active\n");
+            ehci->usbsts |= USBSTS_PSS;
+            ehci->pstate = EST_ACTIVE;
+            // No break, fall through to ACTIVE
+        } else
+            break;
+
+    case EST_ACTIVE:
+        if ( !(ehci->frindex & 7) && !(ehci->usbcmd & USBCMD_PSE)) {
+            DPRINTF("PERIODIC going inactive\n");
+            ehci->usbsts &= ~USBSTS_PSS;
+            ehci->pstate = EST_INACTIVE;
+            break;
+        }
+
+        list = ehci->periodiclistbase & 0xfffff000;
+        /* check that register has been set */
+        if (list == 0) {
+            break;
+        }
+        list |= ((ehci->frindex & 0x1ff8) >> 1);
+
+        cpu_physical_memory_rw(list, (uint8_t *) &entry, sizeof entry, 0);
+        entry = le32_to_cpu(entry);
+
+        DPRINTF("PERIODIC state adv fr=%d.  [%08X] -> %08X\n",
+                ehci->frindex / 8, list, entry);
+        ehci->fetch_addr = entry;
+        ehci->pstate = ehci_advance_state(ehci, 0, EST_FETCHENTRY);
+        break;
+
+    case EST_EXECUTING:
+        DPRINTF("PERIODIC state adv for executing\n");
+        ehci->pstate = ehci_advance_state(ehci, 0, EST_EXECUTING);
+        break;
+
+    default:
+        /* this should only be due to a developer mistake */
+        fprintf(stderr, "ehci: Bad periodic state %d. "
+                "Resetting to active\n", ehci->pstate);
+        ehci->pstate = EST_ACTIVE;
+    }
+}
+
+static void ehci_frame_timer(void *opaque)
+{
+    EHCIState *ehci = opaque;
+    int64_t expire_time, t_now;
+    int usec_elapsed;
+    int frames;
+    int usec_now;
+    int i;
+    int skipped_frames = 0;
+
+
+    t_now = qemu_get_clock_ns(vm_clock);
+    expire_time = t_now + (get_ticks_per_sec() / FRAME_TIMER_FREQ);
+    if (expire_time == t_now) {
+        expire_time++;
+    }
+
+    usec_now = t_now / 1000;
+    usec_elapsed = usec_now - ehci->last_run_usec;
+    frames = usec_elapsed / FRAME_TIMER_USEC;
+    ehci->frame_end_usec = usec_now + FRAME_TIMER_USEC - 10;
+
+    for (i = 0; i < frames; i++) {
+        if ( !(ehci->usbsts & USBSTS_HALT)) {
+            if (ehci->isoch_pause <= 0) {
+                ehci->frindex += 8;
+            }
+
+            if (ehci->frindex > 0x00001fff) {
+                ehci->frindex = 0;
+                ehci_set_interrupt(ehci, USBSTS_FLR);
+            }
+
+            ehci->sofv = (ehci->frindex - 1) >> 3;
+            ehci->sofv &= 0x000003ff;
+        }
+
+        if (frames - i > 10) {
+            skipped_frames++;
+        } else {
+            // TODO could this cause periodic frames to get skipped if async
+            // active?
+            if (ehci->astate != EST_EXECUTING) {
+                ehci_advance_periodic_state(ehci);
+            }
+        }
+
+        ehci->last_run_usec += FRAME_TIMER_USEC;
+    }
+
+#if 0
+    if (skipped_frames) {
+        DPRINTF("WARNING - EHCI skipped %d frames\n", skipped_frames);
+    }
+#endif
+
+    /*  Async is not inside loop since it executes everything it can once
+     *  called
+     */
+    if (ehci->pstate != EST_EXECUTING) {
+        ehci_advance_async_state(ehci);
+    }
+
+    qemu_mod_timer(ehci->frame_timer, expire_time);
+}
+
+static CPUReadMemoryFunc *ehci_readfn[3]={
+    ehci_mem_readb,
+    ehci_mem_readw,
+    ehci_mem_readl
+};
+
+static CPUWriteMemoryFunc *ehci_writefn[3]={
+    ehci_mem_writeb,
+    ehci_mem_writew,
+    ehci_mem_writel
+};
+
+static void ehci_map(PCIDevice *pci_dev, int region_num,
+                     pcibus_t addr, pcibus_t size, int type)
+{
+    EHCIState *s =(EHCIState *)pci_dev;
+
+    DPRINTF("ehci_map: region %d, addr %08" PRIx64 ", size %" PRId64 ", s->mem %08X\n",
+            region_num, addr, size, s->mem);
+    s->mem_base = addr;
+    cpu_register_physical_memory(addr, size, s->mem);
+}
+
+static int usb_ehci_initfn(PCIDevice *dev);
+
+static USBPortOps ehci_port_ops = {
+    .attach = ehci_attach,
+    .detach = ehci_detach,
+    .complete = ehci_async_complete_packet,
+};
+
+static PCIDeviceInfo ehci_info = {
+    .qdev.name    = "usb-ehci",
+    .qdev.size    = sizeof(EHCIState),
+    .init         = usb_ehci_initfn,
+};
+
+static int usb_ehci_initfn(PCIDevice *dev)
+{
+    EHCIState *s = DO_UPCAST(EHCIState, dev, dev);
+    uint8_t *pci_conf = s->dev.config;
+    int i;
+
+    pci_config_set_vendor_id(pci_conf, PCI_VENDOR_ID_INTEL);
+    pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_INTEL_82801D);
+    pci_set_byte(&pci_conf[PCI_REVISION_ID], 0x10);
+    pci_set_byte(&pci_conf[PCI_CLASS_PROG], 0x20);
+    pci_config_set_class(pci_conf, PCI_CLASS_SERIAL_USB);
+    pci_set_byte(&pci_conf[PCI_HEADER_TYPE], PCI_HEADER_TYPE_NORMAL);
+
+    /* capabilities pointer */
+    pci_set_byte(&pci_conf[PCI_CAPABILITY_LIST], 0x00);
+    //pci_set_byte(&pci_conf[PCI_CAPABILITY_LIST], 0x50);
+
+    pci_set_byte(&pci_conf[PCI_INTERRUPT_PIN], 4); // interrupt pin 3
+    pci_set_byte(&pci_conf[PCI_MIN_GNT], 0);
+    pci_set_byte(&pci_conf[PCI_MAX_LAT], 0);
+
+    // pci_conf[0x50] = 0x01; // power management caps
+
+    pci_set_byte(&pci_conf[0x60], 0x20);  // spec release number (2.1.4)
+    pci_set_byte(&pci_conf[0x61], 0x20);  // frame length adjustment (2.1.5)
+    pci_set_word(&pci_conf[0x62], 0x00);  // port wake up capability (2.1.6)
+
+    pci_conf[0x64] = 0x00;
+    pci_conf[0x65] = 0x00;
+    pci_conf[0x66] = 0x00;
+    pci_conf[0x67] = 0x00;
+    pci_conf[0x68] = 0x01;
+    pci_conf[0x69] = 0x00;
+    pci_conf[0x6a] = 0x00;
+    pci_conf[0x6b] = 0x00;  // USBLEGSUP
+    pci_conf[0x6c] = 0x00;
+    pci_conf[0x6d] = 0x00;
+    pci_conf[0x6e] = 0x00;
+    pci_conf[0x6f] = 0xc0;  // USBLEFCTLSTS
+
+    // 2.2 host controller interface version
+    s->mmio[0x00] = (uint8_t) OPREGBASE;
+    s->mmio[0x01] = 0x00;
+    s->mmio[0x02] = 0x00;
+    s->mmio[0x03] = 0x01;        // HC version
+    s->mmio[0x04] = NB_PORTS;    // Number of downstream ports
+    s->mmio[0x05] = 0x00;        // No companion ports at present
+    s->mmio[0x06] = 0x00;
+    s->mmio[0x07] = 0x00;
+    s->mmio[0x08] = 0x80;        // We can cache whole frame, not 64-bit capable
+    s->mmio[0x09] = 0x68;        // EECP
+    s->mmio[0x0a] = 0x00;
+    s->mmio[0x0b] = 0x00;
+
+    s->irq = s->dev.irq[3];
+
+    usb_bus_new(&s->bus, &s->dev.qdev);
+    for(i = 0; i < NB_PORTS; i++) {
+        usb_register_port(&s->bus, &s->ports[i], s, i, &ehci_port_ops,
+                          USB_SPEED_MASK_HIGH);
+        usb_port_location(&s->ports[i], NULL, i+1);
+        s->ports[i].dev = 0;
+    }
+
+    s->frame_timer = qemu_new_timer_ns(vm_clock, ehci_frame_timer, s);
+
+    qemu_register_reset(ehci_reset, s);
+
+    s->mem = cpu_register_io_memory(ehci_readfn, ehci_writefn, s,
+                                    DEVICE_LITTLE_ENDIAN);
+
+    pci_register_bar(&s->dev, 0, MMIO_SIZE, PCI_BASE_ADDRESS_SPACE_MEMORY,
+                                                            ehci_map);
+
+    fprintf(stderr, "*** EHCI support is under development ***\n");
+
+    return 0;
+}
+
+static void ehci_register(void)
+{
+    pci_qdev_register(&ehci_info);
+}
+device_init(ehci_register);
+
+/*
+ * vim: expandtab ts=4
+ */
diff --git a/hw/usb-hid.c b/hw/usb-hid.c
index 89c293c466..53b261c3b9 100644
--- a/hw/usb-hid.c
+++ b/hw/usb-hid.c
@@ -211,6 +211,7 @@ static const USBDescDevice desc_device_mouse = {
             .iConfiguration        = STR_CONFIG_MOUSE,
             .bmAttributes          = 0xa0,
             .bMaxPower             = 50,
+            .nif = 1,
             .ifs = &desc_iface_mouse,
         },
     },
@@ -227,6 +228,7 @@ static const USBDescDevice desc_device_tablet = {
             .iConfiguration        = STR_CONFIG_TABLET,
             .bmAttributes          = 0xa0,
             .bMaxPower             = 50,
+            .nif = 1,
             .ifs = &desc_iface_tablet,
         },
     },
@@ -243,6 +245,7 @@ static const USBDescDevice desc_device_keyboard = {
             .iConfiguration        = STR_CONFIG_KEYBOARD,
             .bmAttributes          = 0xa0,
             .bMaxPower             = 50,
+            .nif = 1,
             .ifs = &desc_iface_keyboard,
         },
     },
@@ -724,13 +727,13 @@ static void usb_hid_set_next_idle(USBHIDState *s, int64_t curtime)
     s->next_idle_clock = curtime + (get_ticks_per_sec() * s->idle * 4) / 1000;
 }
 
-static int usb_hid_handle_control(USBDevice *dev, int request, int value,
-                                  int index, int length, uint8_t *data)
+static int usb_hid_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     USBHIDState *s = (USBHIDState *)dev;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
diff --git a/hw/usb-hub.c b/hw/usb-hub.c
index e0588f891d..6e2a35839d 100644
--- a/hw/usb-hub.c
+++ b/hw/usb-hub.c
@@ -119,6 +119,7 @@ static const USBDescDevice desc_device_hub = {
             .bNumInterfaces        = 1,
             .bConfigurationValue   = 1,
             .bmAttributes          = 0xe0,
+            .nif = 1,
             .ifs = &desc_iface_hub,
         },
     },
@@ -284,13 +285,13 @@ static void usb_hub_handle_reset(USBDevice *dev)
     /* XXX: do it */
 }
 
-static int usb_hub_handle_control(USBDevice *dev, int request, int value,
-                                  int index, int length, uint8_t *data)
+static int usb_hub_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     USBHubState *s = (USBHubState *)dev;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
@@ -494,7 +495,7 @@ static int usb_hub_broadcast_packet(USBHubState *s, USBPacket *p)
         port = &s->ports[i];
         dev = port->port.dev;
         if (dev && (port->wPortStatus & PORT_STAT_ENABLE)) {
-            ret = dev->info->handle_packet(dev, p);
+            ret = usb_handle_packet(dev, p);
             if (ret != USB_RET_NODEV) {
                 return ret;
             }
diff --git a/hw/usb-msd.c b/hw/usb-msd.c
index bd1c3a415f..c59797b27e 100644
--- a/hw/usb-msd.c
+++ b/hw/usb-msd.c
@@ -48,6 +48,7 @@ typedef struct {
     uint32_t data_len;
     uint32_t residue;
     uint32_t tag;
+    SCSIRequest *req;
     SCSIBus bus;
     BlockConf conf;
     SCSIDevice *scsi_dev;
@@ -119,6 +120,7 @@ static const USBDescDevice desc_device_full = {
             .bConfigurationValue   = 1,
             .iConfiguration        = STR_CONFIG_FULL,
             .bmAttributes          = 0xc0,
+            .nif = 1,
             .ifs = &desc_iface_full,
         },
     },
@@ -153,6 +155,7 @@ static const USBDescDevice desc_device_high = {
             .bConfigurationValue   = 1,
             .iConfiguration        = STR_CONFIG_HIGH,
             .bmAttributes          = 0xc0,
+            .nif = 1,
             .ifs = &desc_iface_high,
         },
     },
@@ -189,11 +192,7 @@ static void usb_msd_copy_data(MSDState *s)
     s->scsi_buf += len;
     s->data_len -= len;
     if (s->scsi_len == 0 || s->data_len == 0) {
-        if (s->mode == USB_MSDM_DATAIN) {
-            s->scsi_dev->info->read_data(s->scsi_dev, s->tag);
-        } else if (s->mode == USB_MSDM_DATAOUT) {
-            s->scsi_dev->info->write_data(s->scsi_dev, s->tag);
-        }
+        scsi_req_continue(s->req);
     }
 }
 
@@ -211,47 +210,21 @@ static void usb_msd_send_status(MSDState *s, USBPacket *p)
     memcpy(p->data, &csw, len);
 }
 
-static void usb_msd_command_complete(SCSIBus *bus, int reason, uint32_t tag,
-                                     uint32_t arg)
+static void usb_msd_transfer_data(SCSIRequest *req, uint32_t len)
 {
-    MSDState *s = DO_UPCAST(MSDState, dev.qdev, bus->qbus.parent);
+    MSDState *s = DO_UPCAST(MSDState, dev.qdev, req->bus->qbus.parent);
     USBPacket *p = s->packet;
 
-    if (tag != s->tag) {
-        fprintf(stderr, "usb-msd: Unexpected SCSI Tag 0x%x\n", tag);
+    if (req->tag != s->tag) {
+        fprintf(stderr, "usb-msd: Unexpected SCSI Tag 0x%x\n", req->tag);
     }
-    if (reason == SCSI_REASON_DONE) {
-        DPRINTF("Command complete %d\n", arg);
-        s->residue = s->data_len;
-        s->result = arg != 0;
-        if (s->packet) {
-            if (s->data_len == 0 && s->mode == USB_MSDM_DATAOUT) {
-                /* A deferred packet with no write data remaining must be
-                   the status read packet.  */
-                usb_msd_send_status(s, p);
-                s->mode = USB_MSDM_CBW;
-            } else {
-                if (s->data_len) {
-                    s->data_len -= s->usb_len;
-                    if (s->mode == USB_MSDM_DATAIN)
-                        memset(s->usb_buf, 0, s->usb_len);
-                    s->usb_len = 0;
-                }
-                if (s->data_len == 0)
-                    s->mode = USB_MSDM_CSW;
-            }
-            s->packet = NULL;
-            usb_packet_complete(&s->dev, p);
-        } else if (s->data_len == 0) {
-            s->mode = USB_MSDM_CSW;
-        }
-        return;
-    }
-    s->scsi_len = arg;
-    s->scsi_buf = s->scsi_dev->info->get_buf(s->scsi_dev, tag);
+
+    assert((s->mode == USB_MSDM_DATAOUT) == (req->cmd.mode == SCSI_XFER_TO_DEV));
+    s->scsi_len = len;
+    s->scsi_buf = scsi_req_get_buf(req);
     if (p) {
         usb_msd_copy_data(s);
-        if (s->usb_len == 0) {
+        if (s->packet && s->usb_len == 0) {
             /* Set s->packet to NULL before calling usb_packet_complete
                because another request may be issued before
                usb_packet_complete returns.  */
@@ -262,6 +235,56 @@ static void usb_msd_command_complete(SCSIBus *bus, int reason, uint32_t tag,
     }
 }
 
+static void usb_msd_command_complete(SCSIRequest *req, uint32_t status)
+{
+    MSDState *s = DO_UPCAST(MSDState, dev.qdev, req->bus->qbus.parent);
+    USBPacket *p = s->packet;
+
+    if (req->tag != s->tag) {
+        fprintf(stderr, "usb-msd: Unexpected SCSI Tag 0x%x\n", req->tag);
+    }
+    DPRINTF("Command complete %d\n", status);
+    s->residue = s->data_len;
+    s->result = status != 0;
+    if (s->packet) {
+        if (s->data_len == 0 && s->mode == USB_MSDM_DATAOUT) {
+            /* A deferred packet with no write data remaining must be
+               the status read packet.  */
+            usb_msd_send_status(s, p);
+            s->mode = USB_MSDM_CBW;
+        } else {
+            if (s->data_len) {
+                s->data_len -= s->usb_len;
+                if (s->mode == USB_MSDM_DATAIN) {
+                    memset(s->usb_buf, 0, s->usb_len);
+                }
+                s->usb_len = 0;
+            }
+            if (s->data_len == 0) {
+                s->mode = USB_MSDM_CSW;
+            }
+        }
+        s->packet = NULL;
+        usb_packet_complete(&s->dev, p);
+    } else if (s->data_len == 0) {
+        s->mode = USB_MSDM_CSW;
+    }
+    scsi_req_unref(req);
+    s->req = NULL;
+}
+
+static void usb_msd_request_cancelled(SCSIRequest *req)
+{
+    MSDState *s = DO_UPCAST(MSDState, dev.qdev, req->bus->qbus.parent);
+
+    if (req == s->req) {
+        scsi_req_unref(s->req);
+        s->req = NULL;
+        s->packet = NULL;
+        s->scsi_len = 0;
+    }
+}
+
 static void usb_msd_handle_reset(USBDevice *dev)
 {
     MSDState *s = (MSDState *)dev;
@@ -270,13 +293,13 @@ static void usb_msd_handle_reset(USBDevice *dev)
     s->mode = USB_MSDM_CBW;
 }
 
-static int usb_msd_handle_control(USBDevice *dev, int request, int value,
-                                  int index, int length, uint8_t *data)
+static int usb_msd_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     MSDState *s = (MSDState *)dev;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
@@ -313,12 +336,10 @@ static int usb_msd_handle_control(USBDevice *dev, int request, int value,
     return ret;
 }
 
-static void usb_msd_cancel_io(USBPacket *p, void *opaque)
+static void usb_msd_cancel_io(USBDevice *dev, USBPacket *p)
 {
-    MSDState *s = opaque;
-    s->scsi_dev->info->cancel_io(s->scsi_dev, s->tag);
-    s->packet = NULL;
-    s->scsi_len = 0;
+    MSDState *s = DO_UPCAST(MSDState, dev, dev);
+    scsi_req_cancel(s->req);
 }
 
 static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
@@ -365,15 +386,12 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                     s->tag, cbw.flags, cbw.cmd_len, s->data_len);
             s->residue = 0;
             s->scsi_len = 0;
-            s->scsi_dev->info->send_command(s->scsi_dev, s->tag, cbw.cmd, 0);
+            s->req = scsi_req_new(s->scsi_dev, s->tag, 0);
+            scsi_req_enqueue(s->req, cbw.cmd);
             /* ??? Should check that USB and SCSI data transfer
                directions match.  */
-            if (s->residue == 0) {
-                if (s->mode == USB_MSDM_DATAIN) {
-                    s->scsi_dev->info->read_data(s->scsi_dev, s->tag);
-                } else if (s->mode == USB_MSDM_DATAOUT) {
-                    s->scsi_dev->info->write_data(s->scsi_dev, s->tag);
-                }
+            if (s->mode != USB_MSDM_CSW && s->residue == 0) {
+                scsi_req_continue(s->req);
             }
             ret = len;
             break;
@@ -396,7 +414,6 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             }
             if (s->usb_len) {
                 DPRINTF("Deferring packet %p\n", p);
-                usb_defer_packet(p, usb_msd_cancel_io, s);
                 s->packet = p;
                 ret = USB_RET_ASYNC;
             } else {
@@ -419,7 +436,6 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             if (s->data_len != 0 || len < 13)
                 goto fail;
             /* Waiting for SCSI write to complete.  */
-            usb_defer_packet(p, usb_msd_cancel_io, s);
             s->packet = p;
             ret = USB_RET_ASYNC;
             break;
@@ -453,7 +469,6 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             }
             if (s->usb_len) {
                 DPRINTF("Deferring packet %p\n", p);
-                usb_defer_packet(p, usb_msd_cancel_io, s);
                 s->packet = p;
                 ret = USB_RET_ASYNC;
             } else {
@@ -487,6 +502,12 @@ static void usb_msd_password_cb(void *opaque, int err)
         qdev_unplug(&s->dev.qdev);
 }
 
+static const struct SCSIBusOps usb_msd_scsi_ops = {
+    .transfer_data = usb_msd_transfer_data,
+    .complete = usb_msd_command_complete,
+    .cancel = usb_msd_request_cancelled
+};
+
 static int usb_msd_initfn(USBDevice *dev)
 {
     MSDState *s = DO_UPCAST(MSDState, dev, dev);
@@ -516,7 +537,7 @@ static int usb_msd_initfn(USBDevice *dev)
     }
 
     usb_desc_init(dev);
-    scsi_bus_new(&s->bus, &s->dev.qdev, 0, 1, usb_msd_command_complete);
+    scsi_bus_new(&s->bus, &s->dev.qdev, 0, 1, &usb_msd_scsi_ops);
     s->scsi_dev = scsi_bus_legacy_add_drive(&s->bus, bs, 0, !!s->removable);
     if (!s->scsi_dev) {
         return -1;
@@ -602,6 +623,7 @@ static struct USBDeviceInfo msd_info = {
     .usb_desc       = &desc,
     .init           = usb_msd_initfn,
     .handle_packet  = usb_generic_handle_packet,
+    .cancel_packet  = usb_msd_cancel_io,
     .handle_attach  = usb_desc_attach,
     .handle_reset   = usb_msd_handle_reset,
     .handle_control = usb_msd_handle_control,
diff --git a/hw/usb-musb.c b/hw/usb-musb.c
index 38986d3689..6037193db8 100644
--- a/hw/usb-musb.c
+++ b/hw/usb-musb.c
@@ -601,7 +601,7 @@ static void musb_packet(MUSBState *s, MUSBEndPoint *ep,
     ep->packey[dir].dir = dir;
 
     if (s->port.dev)
-        ret = s->port.dev->info->handle_packet(s->port.dev, &ep->packey[dir].p);
+        ret = usb_handle_packet(s->port.dev, &ep->packey[dir].p);
     else
         ret = USB_RET_NODEV;
 
diff --git a/hw/usb-net.c b/hw/usb-net.c
index bf51bb3890..9be709f7cf 100644
--- a/hw/usb-net.c
+++ b/hw/usb-net.c
@@ -1042,13 +1042,13 @@ static void usb_net_handle_reset(USBDevice *dev)
 {
 }
 
-static int usb_net_handle_control(USBDevice *dev, int request, int value,
-                int index, int length, uint8_t *data)
+static int usb_net_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     USBNetState *s = (USBNetState *) dev;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
diff --git a/hw/usb-ohci.c b/hw/usb-ohci.c
index 32913ebb06..8b966f7907 100644
--- a/hw/usb-ohci.c
+++ b/hw/usb-ohci.c
@@ -748,7 +748,7 @@ static int ohci_service_iso_td(OHCIState *ohci, struct ohci_ed *ed,
             ohci->usb_packet.devep = OHCI_BM(ed->flags, ED_EN);
             ohci->usb_packet.data = ohci->usb_buf;
             ohci->usb_packet.len = len;
-            ret = dev->info->handle_packet(dev, &ohci->usb_packet);
+            ret = usb_handle_packet(dev, &ohci->usb_packet);
             if (ret != USB_RET_NODEV)
                 break;
         }
@@ -944,7 +944,7 @@ static int ohci_service_td(OHCIState *ohci, struct ohci_ed *ed)
             ohci->usb_packet.devep = OHCI_BM(ed->flags, ED_EN);
             ohci->usb_packet.data = ohci->usb_buf;
             ohci->usb_packet.len = len;
-            ret = dev->info->handle_packet(dev, &ohci->usb_packet);
+            ret = usb_handle_packet(dev, &ohci->usb_packet);
             if (ret != USB_RET_NODEV)
                 break;
         }
diff --git a/hw/usb-serial.c b/hw/usb-serial.c
index 6763d52040..59cb0fb2f7 100644
--- a/hw/usb-serial.c
+++ b/hw/usb-serial.c
@@ -146,6 +146,7 @@ static const USBDescDevice desc_device = {
             .bConfigurationValue   = 1,
             .bmAttributes          = 0x80,
             .bMaxPower             = 50,
+            .nif = 1,
             .ifs = &desc_iface0,
         },
     },
@@ -218,14 +219,14 @@ static uint8_t usb_get_modem_lines(USBSerialState *s)
     return ret;
 }
 
-static int usb_serial_handle_control(USBDevice *dev, int request, int value,
-                                  int index, int length, uint8_t *data)
+static int usb_serial_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     USBSerialState *s = (USBSerialState *)dev;
     int ret;
 
     DPRINTF("got control %x, value %x\n",request, value);
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
diff --git a/hw/usb-uhci.c b/hw/usb-uhci.c
index a65e0b3af6..c0de05b4ff 100644
--- a/hw/usb-uhci.c
+++ b/hw/usb-uhci.c
@@ -632,7 +632,7 @@ static int uhci_broadcast_packet(UHCIState *s, USBPacket *p)
         USBDevice *dev = port->port.dev;
 
         if (dev && (port->ctrl & UHCI_PORT_EN))
-            ret = dev->info->handle_packet(dev, p);
+            ret = usb_handle_packet(dev, p);
     }
 
     DPRINTF("uhci: packet exit. ret %d len %d\n", ret, p->len);
@@ -702,11 +702,15 @@ out:
     case USB_RET_STALL:
         td->ctrl |= TD_CTRL_STALL;
         td->ctrl &= ~TD_CTRL_ACTIVE;
+        s->status |= UHCI_STS_USBERR;
+        uhci_update_irq(s);
         return 1;
 
     case USB_RET_BABBLE:
         td->ctrl |= TD_CTRL_BABBLE | TD_CTRL_STALL;
         td->ctrl &= ~TD_CTRL_ACTIVE;
+        s->status |= UHCI_STS_USBERR;
+        uhci_update_irq(s);
         /* frame interrupted */
         return -1;
 
diff --git a/hw/usb-wacom.c b/hw/usb-wacom.c
index 16be7a20cf..9d348e170e 100644
--- a/hw/usb-wacom.c
+++ b/hw/usb-wacom.c
@@ -108,6 +108,7 @@ static const USBDescDevice desc_device_wacom = {
             .bConfigurationValue   = 1,
             .bmAttributes          = 0x80,
             .bMaxPower             = 40,
+            .nif = 1,
             .ifs = &desc_iface_wacom,
         },
     },
@@ -249,13 +250,13 @@ static void usb_wacom_handle_reset(USBDevice *dev)
     s->mode = WACOM_MODE_HID;
 }
 
-static int usb_wacom_handle_control(USBDevice *dev, int request, int value,
-                                    int index, int length, uint8_t *data)
+static int usb_wacom_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     USBWacomState *s = (USBWacomState *) dev;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
diff --git a/hw/usb.c b/hw/usb.c
index d8c0a75c3a..4a39cbcc7d 100644
--- a/hw/usb.c
+++ b/hw/usb.c
@@ -63,9 +63,10 @@ void usb_wakeup(USBDevice *dev)
    protocol)
 */
 
-#define SETUP_STATE_IDLE 0
-#define SETUP_STATE_DATA 1
-#define SETUP_STATE_ACK  2
+#define SETUP_STATE_IDLE  0
+#define SETUP_STATE_SETUP 1
+#define SETUP_STATE_DATA  2
+#define SETUP_STATE_ACK   3
 
 static int do_token_setup(USBDevice *s, USBPacket *p)
 {
@@ -82,10 +83,14 @@ static int do_token_setup(USBDevice *s, USBPacket *p)
     request = (s->setup_buf[0] << 8) | s->setup_buf[1];
     value   = (s->setup_buf[3] << 8) | s->setup_buf[2];
     index   = (s->setup_buf[5] << 8) | s->setup_buf[4];
- 
+
     if (s->setup_buf[0] & USB_DIR_IN) {
-        ret = s->info->handle_control(s, request, value, index, 
+        ret = s->info->handle_control(s, p, request, value, index,
                                       s->setup_len, s->data_buf);
+        if (ret == USB_RET_ASYNC) {
+             s->setup_state = SETUP_STATE_SETUP;
+             return USB_RET_ASYNC;
+        }
         if (ret < 0)
             return ret;
 
@@ -123,9 +128,12 @@ static int do_token_in(USBDevice *s, USBPacket *p)
     switch(s->setup_state) {
     case SETUP_STATE_ACK:
         if (!(s->setup_buf[0] & USB_DIR_IN)) {
-            s->setup_state = SETUP_STATE_IDLE;
-            ret = s->info->handle_control(s, request, value, index,
+            ret = s->info->handle_control(s, p, request, value, index,
                                           s->setup_len, s->data_buf);
+            if (ret == USB_RET_ASYNC) {
+                return USB_RET_ASYNC;
+            }
+            s->setup_state = SETUP_STATE_IDLE;
             if (ret > 0)
                 return 0;
             return ret;
@@ -238,6 +246,36 @@ int usb_generic_handle_packet(USBDevice *s, USBPacket *p)
     }
 }
 
+/* ctrl complete function for devices which use usb_generic_handle_packet and
+   may return USB_RET_ASYNC from their handle_control callback. Device code
+   which does this *must* call this function instead of the normal
+   usb_packet_complete to complete their async control packets. */
+void usb_generic_async_ctrl_complete(USBDevice *s, USBPacket *p)
+{
+    if (p->len < 0) {
+        s->setup_state = SETUP_STATE_IDLE;
+    }
+
+    switch (s->setup_state) {
+    case SETUP_STATE_SETUP:
+        if (p->len < s->setup_len) {
+            s->setup_len = p->len;
+        }
+        s->setup_state = SETUP_STATE_DATA;
+        p->len = 8;
+        break;
+
+    case SETUP_STATE_ACK:
+        s->setup_state = SETUP_STATE_IDLE;
+        p->len = 0;
+        break;
+
+    default:
+        break;
+    }
+    usb_packet_complete(s, p);
+}
+
 /* XXX: fix overflow */
 int set_usb_string(uint8_t *buf, const char *str)
 {
@@ -259,9 +297,54 @@ int set_usb_string(uint8_t *buf, const char *str)
 void usb_send_msg(USBDevice *dev, int msg)
 {
     USBPacket p;
+    int ret;
+
     memset(&p, 0, sizeof(p));
     p.pid = msg;
-    dev->info->handle_packet(dev, &p);
-
+    ret = usb_handle_packet(dev, &p);
     /* This _must_ be synchronous */
+    assert(ret != USB_RET_ASYNC);
+}
+
+/* Hand over a packet to a device for processing.  Return value
+   USB_RET_ASYNC indicates the processing isn't finished yet, the
+   driver will call usb_packet_complete() when done processing it. */
+int usb_handle_packet(USBDevice *dev, USBPacket *p)
+{
+    int ret;
+
+    assert(p->owner == NULL);
+    ret = dev->info->handle_packet(dev, p);
+    if (ret == USB_RET_ASYNC) {
+        if (p->owner == NULL) {
+            p->owner = dev;
+        } else {
+            /* We'll end up here when usb_handle_packet is called
+             * recursively due to a hub being in the chain.  Nothing
+             * to do.  Leave p->owner pointing to the device, not the
+             * hub. */;
+        }
+    }
+    return ret;
+}
+
+/* Notify the controller that an async packet is complete.  This should only
+   be called for packets previously deferred by returning USB_RET_ASYNC from
+   handle_packet. */
+void usb_packet_complete(USBDevice *dev, USBPacket *p)
+{
+    /* Note: p->owner != dev is possible in case dev is a hub */
+    assert(p->owner != NULL);
+    dev->port->ops->complete(dev, p);
+    p->owner = NULL;
+}
+
+/* Cancel an active packet.  The packed must have been deferred by
+   returning USB_RET_ASYNC from handle_packet, and not yet
+   completed.  */
+void usb_cancel_packet(USBPacket * p)
+{
+    assert(p->owner != NULL);
+    p->owner->info->cancel_packet(p->owner, p);
+    p->owner = NULL;
 }
diff --git a/hw/usb.h b/hw/usb.h
index 7e46141fed..98824009b9 100644
--- a/hw/usb.h
+++ b/hw/usb.h
@@ -124,6 +124,7 @@
 #define USB_DT_ENDPOINT			0x05
 #define USB_DT_DEVICE_QUALIFIER         0x06
 #define USB_DT_OTHER_SPEED_CONFIG       0x07
+#define USB_DT_INTERFACE_ASSOC          0x0B
 
 #define USB_ENDPOINT_XFER_CONTROL	0
 #define USB_ENDPOINT_XFER_ISOC		1
@@ -140,6 +141,7 @@ typedef struct USBDesc USBDesc;
 typedef struct USBDescID USBDescID;
 typedef struct USBDescDevice USBDescDevice;
 typedef struct USBDescConfig USBDescConfig;
+typedef struct USBDescIfaceAssoc USBDescIfaceAssoc;
 typedef struct USBDescIface USBDescIface;
 typedef struct USBDescEndpoint USBDescEndpoint;
 typedef struct USBDescOther USBDescOther;
@@ -192,6 +194,11 @@ struct USBDeviceInfo {
     int (*handle_packet)(USBDevice *dev, USBPacket *p);
 
     /*
+     * Called when a packet is canceled.
+     */
+    void (*cancel_packet)(USBDevice *dev, USBPacket *p);
+
+    /*
      * Called when device is destroyed.
      */
     void (*handle_destroy)(USBDevice *dev);
@@ -212,7 +219,7 @@ struct USBDeviceInfo {
      *
      * Returns length or one of the USB_RET_ codes.
      */
-    int (*handle_control)(USBDevice *dev, int request, int value,
+    int (*handle_control)(USBDevice *dev, USBPacket *p, int request, int value,
                           int index, int length, uint8_t *data);
 
     /*
@@ -260,38 +267,17 @@ struct USBPacket {
     uint8_t *data;
     int len;
     /* Internal use by the USB layer.  */
-    USBCallback *cancel_cb;
-    void *cancel_opaque;
+    USBDevice *owner;
 };
 
-/* Defer completion of a USB packet.  The hadle_packet routine should then
-   return USB_RET_ASYNC.  Packets that complete immediately (before
-   handle_packet returns) should not call this method.  */
-static inline void usb_defer_packet(USBPacket *p, USBCallback *cancel,
-                                    void * opaque)
-{
-    p->cancel_cb = cancel;
-    p->cancel_opaque = opaque;
-}
-
-/* Notify the controller that an async packet is complete.  This should only
-   be called for packets previously deferred with usb_defer_packet, and
-   should never be called from within handle_packet.  */
-static inline void usb_packet_complete(USBDevice *dev, USBPacket *p)
-{
-    dev->port->ops->complete(dev, p);
-}
-
-/* Cancel an active packet.  The packed must have been deferred with
-   usb_defer_packet,  and not yet completed.  */
-static inline void usb_cancel_packet(USBPacket * p)
-{
-    p->cancel_cb(p, p->cancel_opaque);
-}
+int usb_handle_packet(USBDevice *dev, USBPacket *p);
+void usb_packet_complete(USBDevice *dev, USBPacket *p);
+void usb_cancel_packet(USBPacket * p);
 
 void usb_attach(USBPort *port, USBDevice *dev);
 void usb_wakeup(USBDevice *dev);
 int usb_generic_handle_packet(USBDevice *s, USBPacket *p);
+void usb_generic_async_ctrl_complete(USBDevice *s, USBPacket *p);
 int set_usb_string(uint8_t *buf, const char *str);
 void usb_send_msg(USBDevice *dev, int msg);
 
diff --git a/hw/virtio-console.c b/hw/virtio-console.c
index de539c4eac..b076331d37 100644
--- a/hw/virtio-console.c
+++ b/hw/virtio-console.c
@@ -74,25 +74,26 @@ static void chr_event(void *opaque, int event)
     }
 }
 
-static int generic_port_init(VirtConsole *vcon, VirtIOSerialPort *port)
+static int virtconsole_initfn(VirtIOSerialPort *port)
 {
+    VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
+    VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev,
+                                           vcon->port.dev.info);
+
+    if (port->id == 0 && !info->is_console) {
+        error_report("Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility.");
+        return -1;
+    }
+
     if (vcon->chr) {
         qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read, chr_event,
                               vcon);
-        vcon->port.info->have_data = flush_buf;
-        vcon->port.info->guest_open = guest_open;
-        vcon->port.info->guest_close = guest_close;
+        info->have_data = flush_buf;
+        info->guest_open = guest_open;
+        info->guest_close = guest_close;
     }
-    return 0;
-}
 
-/* Virtio Console Ports */
-static int virtconsole_initfn(VirtIOSerialPort *port)
-{
-    VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
-
-    port->is_console = true;
-    return generic_port_init(vcon, port);
+    return 0;
 }
 
 static int virtconsole_exitfn(VirtIOSerialPort *port)
@@ -113,10 +114,10 @@ static int virtconsole_exitfn(VirtIOSerialPort *port)
 static VirtIOSerialPortInfo virtconsole_info = {
     .qdev.name     = "virtconsole",
     .qdev.size     = sizeof(VirtConsole),
+    .is_console    = true,
     .init          = virtconsole_initfn,
     .exit          = virtconsole_exitfn,
     .qdev.props = (Property[]) {
-        DEFINE_PROP_UINT8("is_console", VirtConsole, port.is_console, 1),
         DEFINE_PROP_UINT32("nr", VirtConsole, port.id, VIRTIO_CONSOLE_BAD_ID),
         DEFINE_PROP_CHR("chardev", VirtConsole, chr),
         DEFINE_PROP_STRING("name", VirtConsole, port.name),
@@ -130,26 +131,10 @@ static void virtconsole_register(void)
 }
 device_init(virtconsole_register)
 
-/* Generic Virtio Serial Ports */
-static int virtserialport_initfn(VirtIOSerialPort *port)
-{
-    VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
-
-    if (port->id == 0) {
-        /*
-         * Disallow a generic port at id 0, that's reserved for
-         * console ports.
-         */
-        error_report("Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility.");
-        return -1;
-    }
-    return generic_port_init(vcon, port);
-}
-
 static VirtIOSerialPortInfo virtserialport_info = {
     .qdev.name     = "virtserialport",
     .qdev.size     = sizeof(VirtConsole),
-    .init          = virtserialport_initfn,
+    .init          = virtconsole_initfn,
     .exit          = virtconsole_exitfn,
     .qdev.props = (Property[]) {
         DEFINE_PROP_UINT32("nr", VirtConsole, port.id, VIRTIO_CONSOLE_BAD_ID),
diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index f10d48fdb0..9a12104982 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -39,7 +39,7 @@ struct VirtIOSerial {
     /* Arrays of ivqs and ovqs: one per port */
     VirtQueue **ivqs, **ovqs;
 
-    VirtIOSerialBus *bus;
+    VirtIOSerialBus bus;
 
     DeviceState *qdev;
 
@@ -129,9 +129,13 @@ static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
 static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
                                  VirtIODevice *vdev)
 {
+    VirtIOSerialPortInfo *info;
+
     assert(port);
     assert(virtio_queue_ready(vq));
 
+    info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info);
+
     while (!port->throttled) {
         unsigned int i;
 
@@ -149,10 +153,10 @@ static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
             ssize_t ret;
 
             buf_size = port->elem.out_sg[i].iov_len - port->iov_offset;
-            ret = port->info->have_data(port,
-                                        port->elem.out_sg[i].iov_base
-                                          + port->iov_offset,
-                                        buf_size);
+            ret = info->have_data(port,
+                                  port->elem.out_sg[i].iov_base
+                                  + port->iov_offset,
+                                  buf_size);
             if (ret < 0 && ret != -EAGAIN) {
                 /* We don't handle any other type of errors here */
                 abort();
@@ -285,6 +289,13 @@ size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
     return 0;
 }
 
+static void flush_queued_data_bh(void *opaque)
+{
+    VirtIOSerialPort *port = opaque;
+
+    flush_queued_data(port);
+}
+
 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
 {
     if (!port) {
@@ -295,14 +306,14 @@ void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
     if (throttle) {
         return;
     }
-
-    flush_queued_data(port);
+    qemu_bh_schedule(port->bh);
 }
 
 /* Guest wants to notify us of some event */
 static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
 {
     struct VirtIOSerialPort *port;
+    struct VirtIOSerialPortInfo *info;
     struct virtio_console_control cpkt, *gcpkt;
     uint8_t *buffer;
     size_t buffer_len;
@@ -321,11 +332,13 @@ static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
     if (!port && cpkt.event != VIRTIO_CONSOLE_DEVICE_READY)
         return;
 
+    info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info);
+
     switch(cpkt.event) {
     case VIRTIO_CONSOLE_DEVICE_READY:
         if (!cpkt.value) {
             error_report("virtio-serial-bus: Guest failure in adding device %s\n",
-                         vser->bus->qbus.name);
+                         vser->bus.qbus.name);
             break;
         }
         /*
@@ -340,7 +353,7 @@ static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
     case VIRTIO_CONSOLE_PORT_READY:
         if (!cpkt.value) {
             error_report("virtio-serial-bus: Guest failure in adding port %u for device %s\n",
-                         port->id, vser->bus->qbus.name);
+                         port->id, vser->bus.qbus.name);
             break;
         }
         /*
@@ -350,7 +363,7 @@ static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
          * this port is a console port so that the guest can hook it
          * up to hvc.
          */
-        if (port->is_console) {
+        if (info->is_console) {
             send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
         }
 
@@ -379,21 +392,21 @@ static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
          * initialised. If some app is interested in knowing about
          * this event, let it know.
          */
-        if (port->info->guest_ready) {
-            port->info->guest_ready(port);
+        if (info->guest_ready) {
+            info->guest_ready(port);
         }
         break;
 
     case VIRTIO_CONSOLE_PORT_OPEN:
         port->guest_connected = cpkt.value;
-        if (cpkt.value && port->info->guest_open) {
+        if (cpkt.value && info->guest_open) {
             /* Send the guest opened notification if an app is interested */
-            port->info->guest_open(port);
+            info->guest_open(port);
         }
 
-        if (!cpkt.value && port->info->guest_close) {
+        if (!cpkt.value && info->guest_close) {
             /* Send the guest closed notification if an app is interested */
-            port->info->guest_close(port);
+            info->guest_close(port);
         }
         break;
     }
@@ -442,11 +455,13 @@ static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 {
     VirtIOSerial *vser;
     VirtIOSerialPort *port;
+    VirtIOSerialPortInfo *info;
 
     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
     port = find_port_by_vq(vser, vq);
+    info = port ? DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info) : NULL;
 
-    if (!port || !port->host_connected || !port->info->have_data) {
+    if (!port || !port->host_connected || !info->have_data) {
         discard_vq_data(vq, vdev);
         return;
     }
@@ -467,7 +482,7 @@ static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
 
     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 
-    if (vser->bus->max_nr_ports > 1) {
+    if (vser->bus.max_nr_ports > 1) {
         features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
     }
     return features;
@@ -644,16 +659,6 @@ static struct BusInfo virtser_bus_info = {
     .print_dev = virtser_bus_dev_print,
 };
 
-static VirtIOSerialBus *virtser_bus_new(DeviceState *dev)
-{
-    VirtIOSerialBus *bus;
-
-    bus = FROM_QBUS(VirtIOSerialBus, qbus_create(&virtser_bus_info, dev, NULL));
-    bus->qbus.allow_hotplug = 1;
-
-    return bus;
-}
-
 static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 {
     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
@@ -726,13 +731,14 @@ static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
     bool plugging_port0;
 
     port->vser = bus->vser;
+    port->bh = qemu_bh_new(flush_queued_data_bh, port);
 
     /*
      * Is the first console port we're seeing? If so, put it up at
      * location 0. This is done for backward compatibility (old
      * kernel, new qemu).
      */
-    plugging_port0 = port->is_console && !find_port_by_id(port->vser, 0);
+    plugging_port0 = info->is_console && !find_port_by_id(port->vser, 0);
 
     if (find_port_by_id(port->vser, port->id)) {
         error_report("virtio-serial-bus: A port already exists at id %u\n",
@@ -759,7 +765,6 @@ static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
         return -1;
     }
 
-    port->info = info;
     ret = info->init(port);
     if (ret) {
         return ret;
@@ -790,15 +795,18 @@ static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
 static int virtser_port_qdev_exit(DeviceState *qdev)
 {
     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
+    VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev,
+                                           port->dev.info);
     VirtIOSerial *vser = port->vser;
 
+    qemu_bh_delete(port->bh);
     remove_port(port->vser, port->id);
 
     QTAILQ_REMOVE(&vser->ports, port, next);
 
-    if (port->info->exit)
-        port->info->exit(port);
-
+    if (info->exit) {
+        info->exit(port);
+    }
     return 0;
 }
 
@@ -835,11 +843,12 @@ VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
 
     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
-    vser->bus = virtser_bus_new(dev);
-    vser->bus->vser = vser;
+    qbus_create_inplace(&vser->bus.qbus, &virtser_bus_info, dev, NULL);
+    vser->bus.qbus.allow_hotplug = 1;
+    vser->bus.vser = vser;
     QTAILQ_INIT(&vser->ports);
 
-    vser->bus->max_nr_ports = conf->max_virtserial_ports;
+    vser->bus.max_nr_ports = conf->max_virtserial_ports;
     vser->ivqs = qemu_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
     vser->ovqs = qemu_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
 
@@ -859,7 +868,7 @@ VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
     /* control queue: guest to host */
     vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
 
-    for (i = 1; i < vser->bus->max_nr_ports; i++) {
+    for (i = 1; i < vser->bus.max_nr_ports; i++) {
         /* Add a per-port queue for host to guest transfers */
         vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
         /* Add a per-per queue for guest to host transfers */
diff --git a/hw/virtio-serial.h b/hw/virtio-serial.h
index 5eb948e3fd..36e9d222e5 100644
--- a/hw/virtio-serial.h
+++ b/hw/virtio-serial.h
@@ -75,7 +75,6 @@ typedef struct VirtIOSerialPortInfo VirtIOSerialPortInfo;
  */
 struct VirtIOSerialPort {
     DeviceState dev;
-    VirtIOSerialPortInfo *info;
 
     QTAILQ_ENTRY(VirtIOSerialPort) next;
 
@@ -119,8 +118,10 @@ struct VirtIOSerialPort {
     uint32_t iov_idx;
     uint64_t iov_offset;
 
-    /* Identify if this is a port that binds with hvc in the guest */
-    uint8_t is_console;
+    /*
+     * When unthrottling we use a bottom-half to call flush_queued_data.
+     */
+    QEMUBH *bh;
 
     /* Is the corresponding guest device open? */
     bool guest_connected;
@@ -132,6 +133,10 @@ struct VirtIOSerialPort {
 
 struct VirtIOSerialPortInfo {
     DeviceInfo qdev;
+
+    /* Is this a device that binds with hvc in the guest? */
+    bool is_console;
+
     /*
      * The per-port (or per-app) init function that's called when a
      * new device is found on the bus.
diff --git a/trace-events b/trace-events
index 385cb00009..3137a1518f 100644
--- a/trace-events
+++ b/trace-events
@@ -205,6 +205,14 @@ disable usb_set_config(int addr, int config, int ret) "dev %d, config %d, ret %d
 disable usb_clear_device_feature(int addr, int feature, int ret) "dev %d, feature %d, ret %d"
 disable usb_set_device_feature(int addr, int feature, int ret) "dev %d, feature %d, ret %d"
 
+# hw/scsi-bus.c
+disable scsi_req_alloc(int target, int lun, int tag) "target %d lun %d tag %d"
+disable scsi_req_data(int target, int lun, int tag, int len) "target %d lun %d tag %d len %d"
+disable scsi_req_dequeue(int target, int lun, int tag) "target %d lun %d tag %d"
+disable scsi_req_continue(int target, int lun, int tag) "target %d lun %d tag %d"
+disable scsi_req_parsed(int target, int lun, int tag, int cmd, int mode, int xfer, uint64_t lba) "target %d lun %d tag %d command %d dir %d length %d lba %"PRIu64""
+disable scsi_req_parse_bad(int target, int lun, int tag, int cmd) "target %d lun %d tag %d command %d"
+
 # vl.c
 disable vm_state_notify(int running, int reason) "running %d reason %d"
 
diff --git a/usb-bsd.c b/usb-bsd.c
index 50ccd489fe..9bab6e353b 100644
--- a/usb-bsd.c
+++ b/usb-bsd.c
@@ -126,6 +126,7 @@ static void usb_host_handle_reset(USBDevice *dev)
  *  and return appropriate response
  */
 static int usb_host_handle_control(USBDevice *dev,
+                                   USBPacket *p,
                                    int request,
                                    int value,
                                    int index,
diff --git a/usb-linux.c b/usb-linux.c
index 0ef1d2619b..baa6574ef5 100644
--- a/usb-linux.c
+++ b/usb-linux.c
@@ -54,15 +54,7 @@ struct usb_ctrltransfer {
     void *data;
 };
 
-struct usb_ctrlrequest {
-    uint8_t bRequestType;
-    uint8_t bRequest;
-    uint16_t wValue;
-    uint16_t wIndex;
-    uint16_t wLength;
-};
-
-typedef int USBScanFunc(void *opaque, int bus_num, int addr, int devpath,
+typedef int USBScanFunc(void *opaque, int bus_num, int addr, char *port,
                         int class_id, int vendor_id, int product_id,
                         const char *product_name, int speed);
 
@@ -79,6 +71,7 @@ typedef int USBScanFunc(void *opaque, int bus_num, int addr, int devpath,
 #define USBPROCBUS_PATH "/proc/bus/usb"
 #define PRODUCT_NAME_SZ 32
 #define MAX_ENDPOINTS 15
+#define MAX_PORTLEN 16
 #define USBDEVBUS_PATH "/dev/bus/usb"
 #define USBSYSBUS_PATH "/sys/bus/usb"
 
@@ -96,6 +89,9 @@ static int usb_fs_type;
 #define ISO_URB_COUNT 3
 #define INVALID_EP_TYPE 255
 
+/* devio.c limits single requests to 16k */
+#define MAX_USBFS_BUFFER_SIZE 16384
+
 typedef struct AsyncURB AsyncURB;
 
 struct endp_data {
@@ -108,29 +104,10 @@ struct endp_data {
     int max_packet_size;
 };
 
-enum {
-    CTRL_STATE_IDLE = 0,
-    CTRL_STATE_SETUP,
-    CTRL_STATE_DATA,
-    CTRL_STATE_ACK
-};
-
-/*
- * Control transfer state.
- * Note that 'buffer' _must_ follow 'req' field because
- * we need contiguous buffer when we submit control URB.
- */
-struct ctrl_struct {
-    uint16_t len;
-    uint16_t offset;
-    uint8_t  state;
-    struct   usb_ctrlrequest req;
-    uint8_t  buffer[8192];
-};
-
 struct USBAutoFilter {
     uint32_t bus_num;
     uint32_t addr;
+    char     *port;
     uint32_t vendor_id;
     uint32_t product_id;
 };
@@ -146,13 +123,13 @@ typedef struct USBHostDevice {
     int       closing;
     Notifier  exit;
 
-    struct ctrl_struct ctrl;
     struct endp_data endp_table[MAX_ENDPOINTS];
+    QLIST_HEAD(, AsyncURB) aurbs;
 
     /* Host side address */
     int bus_num;
     int addr;
-    int devpath;
+    char port[MAX_PORTLEN];
     struct USBAutoFilter match;
 
     QTAILQ_ENTRY(USBHostDevice) next;
@@ -236,6 +213,22 @@ static int get_iso_buffer_used(USBHostDevice *s, int ep)
     return s->endp_table[ep - 1].iso_buffer_used;
 }
 
+static void set_max_packet_size(USBHostDevice *s, int ep, uint8_t *descriptor)
+{
+    int raw = descriptor[4] + (descriptor[5] << 8);
+    int size, microframes;
+
+    size = raw & 0x7ff;
+    switch ((raw >> 11) & 3) {
+    case 1:  microframes = 2; break;
+    case 2:  microframes = 3; break;
+    default: microframes = 1; break;
+    }
+    DPRINTF("husb: max packet size: 0x%x -> %d x %d\n",
+            raw, microframes, size);
+    s->endp_table[ep - 1].max_packet_size = size * microframes;
+}
+
 static int get_max_packet_size(USBHostDevice *s, int ep)
 {
     return s->endp_table[ep - 1].max_packet_size;
@@ -250,45 +243,31 @@ struct AsyncURB
 {
     struct usbdevfs_urb urb;
     struct usbdevfs_iso_packet_desc isocpd[ISO_FRAME_DESC_PER_URB];
+    USBHostDevice *hdev;
+    QLIST_ENTRY(AsyncURB) next;
 
     /* For regular async urbs */
     USBPacket     *packet;
-    USBHostDevice *hdev;
+    int more; /* large transfer, more urbs follow */
 
     /* For buffered iso handling */
     int iso_frame_idx; /* -1 means in flight */
 };
 
-static AsyncURB *async_alloc(void)
+static AsyncURB *async_alloc(USBHostDevice *s)
 {
-    return (AsyncURB *) qemu_mallocz(sizeof(AsyncURB));
+    AsyncURB *aurb = qemu_mallocz(sizeof(AsyncURB));
+    aurb->hdev = s;
+    QLIST_INSERT_HEAD(&s->aurbs, aurb, next);
+    return aurb;
 }
 
 static void async_free(AsyncURB *aurb)
 {
+    QLIST_REMOVE(aurb, next);
     qemu_free(aurb);
 }
 
-static void async_complete_ctrl(USBHostDevice *s, USBPacket *p)
-{
-    switch(s->ctrl.state) {
-    case CTRL_STATE_SETUP:
-        if (p->len < s->ctrl.len)
-            s->ctrl.len = p->len;
-        s->ctrl.state = CTRL_STATE_DATA;
-        p->len = 8;
-        break;
-
-    case CTRL_STATE_ACK:
-        s->ctrl.state = CTRL_STATE_IDLE;
-        p->len = 0;
-        break;
-
-    default:
-        break;
-    }
-}
-
 static void async_complete(void *opaque)
 {
     USBHostDevice *s = opaque;
@@ -332,10 +311,7 @@ static void async_complete(void *opaque)
         if (p) {
             switch (aurb->urb.status) {
             case 0:
-                p->len = aurb->urb.actual_length;
-                if (aurb->urb.type == USBDEVFS_URB_TYPE_CONTROL) {
-                    async_complete_ctrl(s, p);
-                }
+                p->len += aurb->urb.actual_length;
                 break;
 
             case -EPIPE:
@@ -348,26 +324,36 @@ static void async_complete(void *opaque)
                 break;
             }
 
-            usb_packet_complete(&s->dev, p);
+            if (aurb->urb.type == USBDEVFS_URB_TYPE_CONTROL) {
+                usb_generic_async_ctrl_complete(&s->dev, p);
+            } else if (!aurb->more) {
+                usb_packet_complete(&s->dev, p);
+            }
         }
 
         async_free(aurb);
     }
 }
 
-static void async_cancel(USBPacket *unused, void *opaque)
+static void usb_host_async_cancel(USBDevice *dev, USBPacket *p)
 {
-    AsyncURB *aurb = opaque;
-    USBHostDevice *s = aurb->hdev;
+    USBHostDevice *s = DO_UPCAST(USBHostDevice, dev, dev);
+    AsyncURB *aurb;
 
-    DPRINTF("husb: async cancel. aurb %p\n", aurb);
+    QLIST_FOREACH(aurb, &s->aurbs, next) {
+        if (p != aurb->packet) {
+            continue;
+        }
+
+        DPRINTF("husb: async cancel: packet %p, aurb %p\n", p, aurb);
 
-    /* Mark it as dead (see async_complete above) */
-    aurb->packet = NULL;
+        /* Mark it as dead (see async_complete above) */
+        aurb->packet = NULL;
 
-    int r = ioctl(s->fd, USBDEVFS_DISCARDURB, aurb);
-    if (r < 0) {
-        DPRINTF("husb: async. discard urb failed errno %d\n", errno);
+        int r = ioctl(s->fd, USBDEVFS_DISCARDURB, aurb);
+        if (r < 0) {
+            DPRINTF("husb: async. discard urb failed errno %d\n", errno);
+        }
     }
 }
 
@@ -675,11 +661,13 @@ static int usb_host_handle_iso_data(USBHostDevice *s, USBPacket *p, int in)
     return len;
 }
 
-static int usb_host_handle_data(USBHostDevice *s, USBPacket *p)
+static int usb_host_handle_data(USBDevice *dev, USBPacket *p)
 {
+    USBHostDevice *s = DO_UPCAST(USBHostDevice, dev, dev);
     struct usbdevfs_urb *urb;
     AsyncURB *aurb;
-    int ret;
+    int ret, rem;
+    uint8_t *pbuf;
     uint8_t ep;
 
     if (!is_valid(s, p->devep)) {
@@ -706,37 +694,48 @@ static int usb_host_handle_data(USBHostDevice *s, USBPacket *p)
         return usb_host_handle_iso_data(s, p, p->pid == USB_TOKEN_IN);
     }
 
-    aurb = async_alloc();
-    aurb->hdev   = s;
-    aurb->packet = p;
+    rem = p->len;
+    pbuf = p->data;
+    p->len = 0;
+    while (rem) {
+        aurb = async_alloc(s);
+        aurb->packet = p;
 
-    urb = &aurb->urb;
+        urb = &aurb->urb;
+        urb->endpoint      = ep;
+        urb->type          = USBDEVFS_URB_TYPE_BULK;
+        urb->usercontext   = s;
+        urb->buffer        = pbuf;
 
-    urb->endpoint      = ep;
-    urb->buffer        = p->data;
-    urb->buffer_length = p->len;
-    urb->type          = USBDEVFS_URB_TYPE_BULK;
-    urb->usercontext   = s;
+        if (rem > MAX_USBFS_BUFFER_SIZE) {
+            urb->buffer_length = MAX_USBFS_BUFFER_SIZE;
+            aurb->more         = 1;
+        } else {
+            urb->buffer_length = rem;
+            aurb->more         = 0;
+        }
+        pbuf += urb->buffer_length;
+        rem  -= urb->buffer_length;
 
-    ret = ioctl(s->fd, USBDEVFS_SUBMITURB, urb);
+        ret = ioctl(s->fd, USBDEVFS_SUBMITURB, urb);
 
-    DPRINTF("husb: data submit. ep 0x%x len %u aurb %p\n",
-            urb->endpoint, p->len, aurb);
+        DPRINTF("husb: data submit: ep 0x%x, len %u, more %d, packet %p, aurb %p\n",
+                urb->endpoint, urb->buffer_length, aurb->more, p, aurb);
 
-    if (ret < 0) {
-        DPRINTF("husb: submit failed. errno %d\n", errno);
-        async_free(aurb);
+        if (ret < 0) {
+            DPRINTF("husb: submit failed. errno %d\n", errno);
+            async_free(aurb);
 
-        switch(errno) {
-        case ETIMEDOUT:
-            return USB_RET_NAK;
-        case EPIPE:
-        default:
-            return USB_RET_STALL;
+            switch(errno) {
+            case ETIMEDOUT:
+                return USB_RET_NAK;
+            case EPIPE:
+            default:
+                return USB_RET_STALL;
+            }
         }
     }
 
-    usb_defer_packet(p, async_cancel, aurb);
     return USB_RET_ASYNC;
 }
 
@@ -796,50 +795,43 @@ static int usb_host_set_interface(USBHostDevice *s, int iface, int alt)
     return 0;
 }
 
-static int usb_host_handle_control(USBHostDevice *s, USBPacket *p)
+static int usb_host_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
+    USBHostDevice *s = DO_UPCAST(USBHostDevice, dev, dev);
     struct usbdevfs_urb *urb;
     AsyncURB *aurb;
-    int ret, value, index;
-    int buffer_len;
+    int ret;
 
     /*
      * Process certain standard device requests.
      * These are infrequent and are processed synchronously.
      */
-    value = le16_to_cpu(s->ctrl.req.wValue);
-    index = le16_to_cpu(s->ctrl.req.wIndex);
 
+    /* Note request is (bRequestType << 8) | bRequest */
     DPRINTF("husb: ctrl type 0x%x req 0x%x val 0x%x index %u len %u\n",
-            s->ctrl.req.bRequestType, s->ctrl.req.bRequest, value, index,
-            s->ctrl.len);
+            request >> 8, request & 0xff, value, index, length);
 
-    if (s->ctrl.req.bRequestType == 0) {
-        switch (s->ctrl.req.bRequest) {
-        case USB_REQ_SET_ADDRESS:
-            return usb_host_set_address(s, value);
+    switch (request) {
+    case DeviceOutRequest | USB_REQ_SET_ADDRESS:
+        return usb_host_set_address(s, value);
 
-        case USB_REQ_SET_CONFIGURATION:
-            return usb_host_set_config(s, value & 0xff);
-        }
-    }
+    case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
+        return usb_host_set_config(s, value & 0xff);
 
-    if (s->ctrl.req.bRequestType == 1 &&
-                  s->ctrl.req.bRequest == USB_REQ_SET_INTERFACE) {
+    case InterfaceOutRequest | USB_REQ_SET_INTERFACE:
         return usb_host_set_interface(s, index, value);
     }
 
     /* The rest are asynchronous */
 
-    buffer_len = 8 + s->ctrl.len;
-    if (buffer_len > sizeof(s->ctrl.buffer)) {
-        fprintf(stderr, "husb: ctrl buffer too small (%u > %zu)\n",
-                buffer_len, sizeof(s->ctrl.buffer));
+    if (length > sizeof(dev->data_buf)) {
+        fprintf(stderr, "husb: ctrl buffer too small (%d > %zu)\n",
+                length, sizeof(dev->data_buf));
         return USB_RET_STALL;
     }
 
-    aurb = async_alloc();
-    aurb->hdev   = s;
+    aurb = async_alloc(s);
     aurb->packet = p;
 
     /*
@@ -853,8 +845,8 @@ static int usb_host_handle_control(USBHostDevice *s, USBPacket *p)
     urb->type     = USBDEVFS_URB_TYPE_CONTROL;
     urb->endpoint = p->devep;
 
-    urb->buffer        = &s->ctrl.req;
-    urb->buffer_length = buffer_len;
+    urb->buffer        = &dev->setup_buf;
+    urb->buffer_length = length + 8;
 
     urb->usercontext = s;
 
@@ -875,174 +867,9 @@ static int usb_host_handle_control(USBHostDevice *s, USBPacket *p)
         }
     }
 
-    usb_defer_packet(p, async_cancel, aurb);
     return USB_RET_ASYNC;
 }
 
-static int do_token_setup(USBDevice *dev, USBPacket *p)
-{
-    USBHostDevice *s = (USBHostDevice *) dev;
-    int ret = 0;
-
-    if (p->len != 8) {
-        return USB_RET_STALL;
-    }
-
-    memcpy(&s->ctrl.req, p->data, 8);
-    s->ctrl.len    = le16_to_cpu(s->ctrl.req.wLength);
-    s->ctrl.offset = 0;
-    s->ctrl.state  = CTRL_STATE_SETUP;
-
-    if (s->ctrl.req.bRequestType & USB_DIR_IN) {
-        ret = usb_host_handle_control(s, p);
-        if (ret < 0) {
-            return ret;
-        }
-
-        if (ret < s->ctrl.len) {
-            s->ctrl.len = ret;
-        }
-        s->ctrl.state = CTRL_STATE_DATA;
-    } else {
-        if (s->ctrl.len == 0) {
-            s->ctrl.state = CTRL_STATE_ACK;
-        } else {
-            s->ctrl.state = CTRL_STATE_DATA;
-        }
-    }
-
-    return ret;
-}
-
-static int do_token_in(USBDevice *dev, USBPacket *p)
-{
-    USBHostDevice *s = (USBHostDevice *) dev;
-    int ret = 0;
-
-    if (p->devep != 0) {
-        return usb_host_handle_data(s, p);
-    }
-
-    switch(s->ctrl.state) {
-    case CTRL_STATE_ACK:
-        if (!(s->ctrl.req.bRequestType & USB_DIR_IN)) {
-            ret = usb_host_handle_control(s, p);
-            if (ret == USB_RET_ASYNC) {
-                return USB_RET_ASYNC;
-            }
-            s->ctrl.state = CTRL_STATE_IDLE;
-            return ret > 0 ? 0 : ret;
-        }
-
-        return 0;
-
-    case CTRL_STATE_DATA:
-        if (s->ctrl.req.bRequestType & USB_DIR_IN) {
-            int len = s->ctrl.len - s->ctrl.offset;
-            if (len > p->len) {
-                len = p->len;
-            }
-            memcpy(p->data, s->ctrl.buffer + s->ctrl.offset, len);
-            s->ctrl.offset += len;
-            if (s->ctrl.offset >= s->ctrl.len) {
-                s->ctrl.state = CTRL_STATE_ACK;
-            }
-            return len;
-        }
-
-        s->ctrl.state = CTRL_STATE_IDLE;
-        return USB_RET_STALL;
-
-    default:
-        return USB_RET_STALL;
-    }
-}
-
-static int do_token_out(USBDevice *dev, USBPacket *p)
-{
-    USBHostDevice *s = (USBHostDevice *) dev;
-
-    if (p->devep != 0) {
-        return usb_host_handle_data(s, p);
-    }
-
-    switch(s->ctrl.state) {
-    case CTRL_STATE_ACK:
-        if (s->ctrl.req.bRequestType & USB_DIR_IN) {
-            s->ctrl.state = CTRL_STATE_IDLE;
-            /* transfer OK */
-        } else {
-            /* ignore additional output */
-        }
-        return 0;
-
-    case CTRL_STATE_DATA:
-        if (!(s->ctrl.req.bRequestType & USB_DIR_IN)) {
-            int len = s->ctrl.len - s->ctrl.offset;
-            if (len > p->len) {
-                len = p->len;
-            }
-            memcpy(s->ctrl.buffer + s->ctrl.offset, p->data, len);
-            s->ctrl.offset += len;
-            if (s->ctrl.offset >= s->ctrl.len) {
-                s->ctrl.state = CTRL_STATE_ACK;
-            }
-            return len;
-        }
-
-        s->ctrl.state = CTRL_STATE_IDLE;
-        return USB_RET_STALL;
-
-    default:
-        return USB_RET_STALL;
-    }
-}
-
-/*
- * Packet handler.
- * Called by the HC (host controller).
- *
- * Returns length of the transaction or one of the USB_RET_XXX codes.
- */
-static int usb_host_handle_packet(USBDevice *s, USBPacket *p)
-{
-    switch(p->pid) {
-    case USB_MSG_ATTACH:
-        s->state = USB_STATE_ATTACHED;
-        return 0;
-
-    case USB_MSG_DETACH:
-        s->state = USB_STATE_NOTATTACHED;
-        return 0;
-
-    case USB_MSG_RESET:
-        s->remote_wakeup = 0;
-        s->addr = 0;
-        s->state = USB_STATE_DEFAULT;
-        s->info->handle_reset(s);
-        return 0;
-    }
-
-    /* Rest of the PIDs must match our address */
-    if (s->state < USB_STATE_DEFAULT || p->devaddr != s->addr) {
-        return USB_RET_NODEV;
-    }
-
-    switch (p->pid) {
-    case USB_TOKEN_SETUP:
-        return do_token_setup(s, p);
-
-    case USB_TOKEN_IN:
-        return do_token_in(s, p);
-
-    case USB_TOKEN_OUT:
-        return do_token_out(s, p);
-
-    default:
-        return USB_RET_STALL;
-    }
-}
-
 static int usb_linux_get_configuration(USBHostDevice *s)
 {
     uint8_t configuration;
@@ -1053,7 +880,7 @@ static int usb_linux_get_configuration(USBHostDevice *s)
         char device_name[32], line[1024];
         int configuration;
 
-        sprintf(device_name, "%d-%d", s->bus_num, s->devpath);
+        sprintf(device_name, "%d-%s", s->bus_num, s->port);
 
         if (!usb_host_read_file(line, sizeof(line), "bConfigurationValue",
                                 device_name)) {
@@ -1099,7 +926,7 @@ static uint8_t usb_linux_get_alt_setting(USBHostDevice *s,
         char device_name[64], line[1024];
         int alt_setting;
 
-        sprintf(device_name, "%d-%d:%d.%d", s->bus_num, s->devpath,
+        sprintf(device_name, "%d-%s:%d.%d", s->bus_num, s->port,
                 (int)configuration, (int)interface);
 
         if (!usb_host_read_file(line, sizeof(line), "bAlternateSetting",
@@ -1195,8 +1022,7 @@ static int usb_linux_update_endp_table(USBHostDevice *s)
                 break;
             case 0x01:
                 type = USBDEVFS_URB_TYPE_ISO;
-                s->endp_table[(devep & 0xf) - 1].max_packet_size =
-                    descriptors[i + 4] + (descriptors[i + 5] << 8);
+                set_max_packet_size(s, (devep & 0xf), descriptors + i);
                 break;
             case 0x02:
                 type = USBDEVFS_URB_TYPE_BULK;
@@ -1218,7 +1044,7 @@ static int usb_linux_update_endp_table(USBHostDevice *s)
 }
 
 static int usb_host_open(USBHostDevice *dev, int bus_num,
-                         int addr, int devpath, const char *prod_name)
+                         int addr, char *port, const char *prod_name)
 {
     int fd = -1, ret;
     struct usbdevfs_connectinfo ci;
@@ -1244,7 +1070,7 @@ static int usb_host_open(USBHostDevice *dev, int bus_num,
 
     dev->bus_num = bus_num;
     dev->addr = addr;
-    dev->devpath = devpath;
+    strcpy(dev->port, port);
     dev->fd = fd;
 
     /* read the device description */
@@ -1368,7 +1194,10 @@ static struct USBDeviceInfo usb_host_dev_info = {
     .qdev.name      = "usb-host",
     .qdev.size      = sizeof(USBHostDevice),
     .init           = usb_host_initfn,
-    .handle_packet  = usb_host_handle_packet,
+    .handle_packet  = usb_generic_handle_packet,
+    .cancel_packet  = usb_host_async_cancel,
+    .handle_data    = usb_host_handle_data,
+    .handle_control = usb_host_handle_control,
     .handle_reset   = usb_host_handle_reset,
     .handle_destroy = usb_host_handle_destroy,
     .usbdevice_name = "host",
@@ -1376,6 +1205,7 @@ static struct USBDeviceInfo usb_host_dev_info = {
     .qdev.props     = (Property[]) {
         DEFINE_PROP_UINT32("hostbus",  USBHostDevice, match.bus_num,    0),
         DEFINE_PROP_UINT32("hostaddr", USBHostDevice, match.addr,       0),
+        DEFINE_PROP_STRING("hostport", USBHostDevice, match.port),
         DEFINE_PROP_HEX32("vendorid",  USBHostDevice, match.vendor_id,  0),
         DEFINE_PROP_HEX32("productid", USBHostDevice, match.product_id, 0),
         DEFINE_PROP_END_OF_LIST(),
@@ -1616,8 +1446,9 @@ static int usb_host_scan_sys(void *opaque, USBScanFunc *func)
 {
     DIR *dir = NULL;
     char line[1024];
-    int bus_num, addr, devpath, speed, class_id, product_id, vendor_id;
+    int bus_num, addr, speed, class_id, product_id, vendor_id;
     int ret = 0;
+    char port[MAX_PORTLEN];
     char product_name[512];
     struct dirent *de;
 
@@ -1629,12 +1460,8 @@ static int usb_host_scan_sys(void *opaque, USBScanFunc *func)
 
     while ((de = readdir(dir))) {
         if (de->d_name[0] != '.' && !strchr(de->d_name, ':')) {
-            char *tmpstr = de->d_name;
-            if (!strncmp(de->d_name, "usb", 3)) {
-                tmpstr += 3;
-            }
-            if (sscanf(tmpstr, "%d-%d", &bus_num, &devpath) < 1) {
-                goto the_end;
+            if (sscanf(de->d_name, "%d-%7[0-9.]", &bus_num, port) < 2) {
+                continue;
             }
 
             if (!usb_host_read_file(line, sizeof(line), "devnum", de->d_name)) {
@@ -1686,7 +1513,7 @@ static int usb_host_scan_sys(void *opaque, USBScanFunc *func)
                 speed = USB_SPEED_FULL;
             }
 
-            ret = func(opaque, bus_num, addr, devpath, class_id, vendor_id,
+            ret = func(opaque, bus_num, addr, port, class_id, vendor_id,
                        product_id, product_name, speed);
             if (ret) {
                 goto the_end;
@@ -1777,7 +1604,7 @@ static int usb_host_scan(void *opaque, USBScanFunc *func)
 
 static QEMUTimer *usb_auto_timer;
 
-static int usb_host_auto_scan(void *opaque, int bus_num, int addr, int devpath,
+static int usb_host_auto_scan(void *opaque, int bus_num, int addr, char *port,
                               int class_id, int vendor_id, int product_id,
                               const char *product_name, int speed)
 {
@@ -1797,6 +1624,9 @@ static int usb_host_auto_scan(void *opaque, int bus_num, int addr, int devpath,
         if (f->addr > 0 && f->addr != addr) {
             continue;
         }
+        if (f->port != NULL && (port == NULL || strcmp(f->port, port) != 0)) {
+            continue;
+        }
 
         if (f->vendor_id > 0 && f->vendor_id != vendor_id) {
             continue;
@@ -1813,7 +1643,7 @@ static int usb_host_auto_scan(void *opaque, int bus_num, int addr, int devpath,
         }
         DPRINTF("husb: auto open: bus_num %d addr %d\n", bus_num, addr);
 
-        usb_host_open(s, bus_num, addr, devpath, product_name);
+        usb_host_open(s, bus_num, addr, port, product_name);
     }
 
     return 0;
@@ -1935,8 +1765,8 @@ static const char *usb_class_str(uint8_t class)
     return p->class_name;
 }
 
-static void usb_info_device(Monitor *mon, int bus_num, int addr, int class_id,
-                            int vendor_id, int product_id,
+static void usb_info_device(Monitor *mon, int bus_num, int addr, char *port,
+                            int class_id, int vendor_id, int product_id,
                             const char *product_name,
                             int speed)
 {
@@ -1957,8 +1787,8 @@ static void usb_info_device(Monitor *mon, int bus_num, int addr, int class_id,
         break;
     }
 
-    monitor_printf(mon, "  Device %d.%d, speed %s Mb/s\n",
-                bus_num, addr, speed_str);
+    monitor_printf(mon, "  Bus %d, Addr %d, Port %s, Speed %s Mb/s\n",
+                   bus_num, addr, port, speed_str);
     class_str = usb_class_str(class_id);
     if (class_str) {
         monitor_printf(mon, "    %s:", class_str);
@@ -1973,14 +1803,14 @@ static void usb_info_device(Monitor *mon, int bus_num, int addr, int class_id,
 }
 
 static int usb_host_info_device(void *opaque, int bus_num, int addr,
-                                int devpath, int class_id,
+                                char *path, int class_id,
                                 int vendor_id, int product_id,
                                 const char *product_name,
                                 int speed)
 {
     Monitor *mon = opaque;
 
-    usb_info_device(mon, bus_num, addr, class_id, vendor_id, product_id,
+    usb_info_device(mon, bus_num, addr, path, class_id, vendor_id, product_id,
                     product_name, speed);
     return 0;
 }
@@ -2022,7 +1852,7 @@ void usb_host_info(Monitor *mon)
         dec2str(f->addr, addr, sizeof(addr));
         hex2str(f->vendor_id, vid, sizeof(vid));
         hex2str(f->product_id, pid, sizeof(pid));
-        monitor_printf(mon, "    Device %s.%s ID %s:%s\n",
-                       bus, addr, vid, pid);
+        monitor_printf(mon, "    Bus %s, Addr %s, Port %s, ID %s:%s\n",
+                       bus, addr, f->port ? f->port : "*", vid, pid);
     }
 }