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-rw-r--r--MAINTAINERS1
-rw-r--r--docs/devel/migration/vfio.rst19
-rw-r--r--hw/core/machine.c1
-rw-r--r--hw/vfio-user/container.c6
-rw-r--r--hw/vfio-user/proxy.c10
-rw-r--r--hw/vfio/device.c6
-rw-r--r--hw/vfio/helpers.c17
-rw-r--r--hw/vfio/migration-multifd.c100
-rw-r--r--hw/vfio/migration-multifd.h3
-rw-r--r--hw/vfio/migration.c10
-rw-r--r--hw/vfio/pci.c48
-rw-r--r--hw/vfio/pci.h6
-rw-r--r--hw/vfio/trace-events1
-rw-r--r--hw/vfio/vfio-helpers.h2
-rw-r--r--hw/vfio/vfio-migration-internal.h1
-rw-r--r--include/hw/vfio/vfio-device.h2
16 files changed, 212 insertions, 21 deletions
diff --git a/MAINTAINERS b/MAINTAINERS
index e88ed2c0a9..30e9b71e6e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4287,6 +4287,7 @@ F: tests/functional/test_multiprocess.py
 VFIO-USER:
 M: John Levon <john.levon@nutanix.com>
 M: Thanos Makatos <thanos.makatos@nutanix.com>
+M: Cédric Le Goater <clg@redhat.com>
 S: Supported
 F: docs/interop/vfio-user.rst
 F: docs/system/devices/vfio-user.rst
diff --git a/docs/devel/migration/vfio.rst b/docs/devel/migration/vfio.rst
index 2d8e5ca9dd..0790e5031d 100644
--- a/docs/devel/migration/vfio.rst
+++ b/docs/devel/migration/vfio.rst
@@ -247,3 +247,22 @@ The multifd VFIO device state transfer is controlled by
 "x-migration-multifd-transfer" VFIO device property. This property defaults to
 AUTO, which means that VFIO device state transfer via multifd channels is
 attempted in configurations that otherwise support it.
+
+Since the target QEMU needs to load device state buffers in-order it needs to
+queue incoming buffers until they can be loaded into the device.
+This means that a malicious QEMU source could theoretically cause the target
+QEMU to allocate unlimited amounts of memory for such buffers-in-flight.
+
+The "x-migration-max-queued-buffers-size" property allows capping the total size
+of these VFIO device state buffers queued at the destination.
+
+Because a malicious QEMU source causing OOM on the target is not expected to be
+a realistic threat in most of VFIO live migration use cases and the right value
+depends on the particular setup by default this queued buffers size limit is
+disabled by setting it to UINT64_MAX.
+
+Some host platforms (like ARM64) require that VFIO device config is loaded only
+after all iterables were loaded, during non-iterables loading phase.
+Such interlocking is controlled by "x-migration-load-config-after-iter" VFIO
+device property, which in its default setting (AUTO) does so only on platforms
+that actually require it.
diff --git a/hw/core/machine.c b/hw/core/machine.c
index ceee058cad..8063271a74 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -39,6 +39,7 @@
 
 GlobalProperty hw_compat_10_0[] = {
     { "scsi-hd", "dpofua", "off" },
+    { "vfio-pci", "x-migration-load-config-after-iter", "off" },
 };
 const size_t hw_compat_10_0_len = G_N_ELEMENTS(hw_compat_10_0);
 
diff --git a/hw/vfio-user/container.c b/hw/vfio-user/container.c
index d318e6a339..d589dd90f5 100644
--- a/hw/vfio-user/container.c
+++ b/hw/vfio-user/container.c
@@ -64,8 +64,6 @@ static int vfio_user_dma_unmap(const VFIOContainerBase *bcontainer,
                               0, &local_err)) {
             error_report_err(local_err);
             ret = -EFAULT;
-        } else {
-            ret = 0;
         }
     } else {
         if (!vfio_user_send_wait(container->proxy, &msgp->hdr, NULL,
@@ -92,7 +90,7 @@ static int vfio_user_dma_map(const VFIOContainerBase *bcontainer, hwaddr iova,
                                                 bcontainer);
     int fd = memory_region_get_fd(mrp);
     Error *local_err = NULL;
-    int ret;
+    int ret = 0;
 
     VFIOUserFDs *fds = NULL;
     VFIOUserDMAMap *msgp = g_malloc0(sizeof(*msgp));
@@ -135,8 +133,6 @@ static int vfio_user_dma_map(const VFIOContainerBase *bcontainer, hwaddr iova,
                               0, &local_err)) {
             error_report_err(local_err);
             ret = -EFAULT;
-        } else {
-            ret = 0;
         }
     } else {
         VFIOUserFDs local_fds = { 1, 0, &fd };
diff --git a/hw/vfio-user/proxy.c b/hw/vfio-user/proxy.c
index c418954440..2275d3fe39 100644
--- a/hw/vfio-user/proxy.c
+++ b/hw/vfio-user/proxy.c
@@ -32,7 +32,6 @@ static void vfio_user_recycle(VFIOUserProxy *proxy, VFIOUserMsg *msg);
 
 static void vfio_user_recv(void *opaque);
 static void vfio_user_send(void *opaque);
-static void vfio_user_cb(void *opaque);
 
 static void vfio_user_request(void *opaque);
 
@@ -492,7 +491,7 @@ static void vfio_user_send(void *opaque)
     }
 }
 
-static void vfio_user_cb(void *opaque)
+static void vfio_user_close_cb(void *opaque)
 {
     VFIOUserProxy *proxy = opaque;
 
@@ -984,8 +983,11 @@ void vfio_user_disconnect(VFIOUserProxy *proxy)
      * handler to run after the proxy fd handlers were
      * deleted above.
      */
-    aio_bh_schedule_oneshot(proxy->ctx, vfio_user_cb, proxy);
-    qemu_cond_wait(&proxy->close_cv, &proxy->lock);
+    aio_bh_schedule_oneshot(proxy->ctx, vfio_user_close_cb, proxy);
+
+    while (proxy->state != VFIO_PROXY_CLOSED) {
+        qemu_cond_wait(&proxy->close_cv, &proxy->lock);
+    }
 
     /* we now hold the only ref to proxy */
     qemu_mutex_unlock(&proxy->lock);
diff --git a/hw/vfio/device.c b/hw/vfio/device.c
index 96cf21462c..52a1996dc4 100644
--- a/hw/vfio/device.c
+++ b/hw/vfio/device.c
@@ -463,6 +463,8 @@ void vfio_device_detach(VFIODevice *vbasedev)
 void vfio_device_prepare(VFIODevice *vbasedev, VFIOContainerBase *bcontainer,
                          struct vfio_device_info *info)
 {
+    int i;
+
     vbasedev->num_irqs = info->num_irqs;
     vbasedev->num_regions = info->num_regions;
     vbasedev->flags = info->flags;
@@ -477,6 +479,9 @@ void vfio_device_prepare(VFIODevice *vbasedev, VFIOContainerBase *bcontainer,
                                vbasedev->num_regions);
     if (vbasedev->use_region_fds) {
         vbasedev->region_fds = g_new0(int, vbasedev->num_regions);
+        for (i = 0; i < vbasedev->num_regions; i++) {
+            vbasedev->region_fds[i] = -1;
+        }
     }
 }
 
@@ -489,7 +494,6 @@ void vfio_device_unprepare(VFIODevice *vbasedev)
         if (vbasedev->region_fds != NULL && vbasedev->region_fds[i] != -1) {
             close(vbasedev->region_fds[i]);
         }
-
     }
 
     g_clear_pointer(&vbasedev->reginfo, g_free);
diff --git a/hw/vfio/helpers.c b/hw/vfio/helpers.c
index 9a5f621545..23d13e5db5 100644
--- a/hw/vfio/helpers.c
+++ b/hw/vfio/helpers.c
@@ -209,3 +209,20 @@ retry:
 
     return info;
 }
+
+bool vfio_arch_wants_loading_config_after_iter(void)
+{
+    /*
+     * Starting the config load only after all iterables were loaded (during
+     * non-iterables loading phase) is required for ARM64 due to this platform
+     * VFIO dependency on interrupt controller being loaded first.
+     *
+     * See commit d329f5032e17 ("vfio: Move the saving of the config space to
+     * the right place in VFIO migration").
+     */
+#if defined(TARGET_ARM)
+    return true;
+#else
+    return false;
+#endif
+}
diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c
index 9dc70fdf16..e4785031a7 100644
--- a/hw/vfio/migration-multifd.c
+++ b/hw/vfio/migration-multifd.c
@@ -22,6 +22,7 @@
 #include "migration-multifd.h"
 #include "vfio-migration-internal.h"
 #include "trace.h"
+#include "vfio-helpers.h"
 
 #define VFIO_DEVICE_STATE_CONFIG_STATE (1)
 
@@ -34,6 +35,18 @@ typedef struct VFIODeviceStatePacket {
     uint8_t data[0];
 } QEMU_PACKED VFIODeviceStatePacket;
 
+bool vfio_load_config_after_iter(VFIODevice *vbasedev)
+{
+    if (vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_ON) {
+        return true;
+    } else if (vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_OFF) {
+        return false;
+    }
+
+    assert(vbasedev->migration_load_config_after_iter == ON_OFF_AUTO_AUTO);
+    return vfio_arch_wants_loading_config_after_iter();
+}
+
 /* type safety */
 typedef struct VFIOStateBuffers {
     GArray *array;
@@ -49,12 +62,16 @@ typedef struct VFIOMultifd {
     bool load_bufs_thread_running;
     bool load_bufs_thread_want_exit;
 
+    bool load_bufs_iter_done;
+    QemuCond load_bufs_iter_done_cond;
+
     VFIOStateBuffers load_bufs;
     QemuCond load_bufs_buffer_ready_cond;
     QemuCond load_bufs_thread_finished_cond;
     QemuMutex load_bufs_mutex; /* Lock order: this lock -> BQL */
     uint32_t load_buf_idx;
     uint32_t load_buf_idx_last;
+    size_t load_buf_queued_pending_buffers_size;
 } VFIOMultifd;
 
 static void vfio_state_buffer_clear(gpointer data)
@@ -111,6 +128,7 @@ static bool vfio_load_state_buffer_insert(VFIODevice *vbasedev,
     VFIOMigration *migration = vbasedev->migration;
     VFIOMultifd *multifd = migration->multifd;
     VFIOStateBuffer *lb;
+    size_t data_size = packet_total_size - sizeof(*packet);
 
     vfio_state_buffers_assert_init(&multifd->load_bufs);
     if (packet->idx >= vfio_state_buffers_size_get(&multifd->load_bufs)) {
@@ -126,8 +144,19 @@ static bool vfio_load_state_buffer_insert(VFIODevice *vbasedev,
 
     assert(packet->idx >= multifd->load_buf_idx);
 
-    lb->data = g_memdup2(&packet->data, packet_total_size - sizeof(*packet));
-    lb->len = packet_total_size - sizeof(*packet);
+    multifd->load_buf_queued_pending_buffers_size += data_size;
+    if (multifd->load_buf_queued_pending_buffers_size >
+        vbasedev->migration_max_queued_buffers_size) {
+        error_setg(errp,
+                   "%s: queuing state buffer %" PRIu32
+                   " would exceed the size max of %" PRIu64,
+                   vbasedev->name, packet->idx,
+                   vbasedev->migration_max_queued_buffers_size);
+        return false;
+    }
+
+    lb->data = g_memdup2(&packet->data, data_size);
+    lb->len = data_size;
     lb->is_present = true;
 
     return true;
@@ -311,6 +340,9 @@ static bool vfio_load_state_buffer_write(VFIODevice *vbasedev,
         assert(wr_ret <= buf_len);
         buf_len -= wr_ret;
         buf_cur += wr_ret;
+
+        assert(multifd->load_buf_queued_pending_buffers_size >= wr_ret);
+        multifd->load_buf_queued_pending_buffers_size -= wr_ret;
     }
 
     trace_vfio_load_state_device_buffer_load_end(vbasedev->name,
@@ -393,6 +425,22 @@ static bool vfio_load_bufs_thread(void *opaque, bool *should_quit, Error **errp)
         multifd->load_buf_idx++;
     }
 
+    if (vfio_load_config_after_iter(vbasedev)) {
+        while (!multifd->load_bufs_iter_done) {
+            qemu_cond_wait(&multifd->load_bufs_iter_done_cond,
+                           &multifd->load_bufs_mutex);
+
+            /*
+             * Need to re-check cancellation immediately after wait in case
+             * cond was signalled by vfio_load_cleanup_load_bufs_thread().
+             */
+            if (vfio_load_bufs_thread_want_exit(multifd, should_quit)) {
+                error_setg(errp, "operation cancelled");
+                goto thread_exit;
+            }
+        }
+    }
+
     if (!vfio_load_bufs_thread_load_config(vbasedev, errp)) {
         goto thread_exit;
     }
@@ -412,6 +460,48 @@ thread_exit:
     return ret;
 }
 
+int vfio_load_state_config_load_ready(VFIODevice *vbasedev)
+{
+    VFIOMigration *migration = vbasedev->migration;
+    VFIOMultifd *multifd = migration->multifd;
+    int ret = 0;
+
+    if (!vfio_multifd_transfer_enabled(vbasedev)) {
+        error_report("%s: got DEV_CONFIG_LOAD_READY outside multifd transfer",
+                     vbasedev->name);
+        return -EINVAL;
+    }
+
+    if (!vfio_load_config_after_iter(vbasedev)) {
+        error_report("%s: got DEV_CONFIG_LOAD_READY but was disabled",
+                     vbasedev->name);
+        return -EINVAL;
+    }
+
+    assert(multifd);
+
+    /* The lock order is load_bufs_mutex -> BQL so unlock BQL here first */
+    bql_unlock();
+    WITH_QEMU_LOCK_GUARD(&multifd->load_bufs_mutex) {
+        if (multifd->load_bufs_iter_done) {
+            /* Can't print error here as we're outside BQL */
+            ret = -EINVAL;
+            break;
+        }
+
+        multifd->load_bufs_iter_done = true;
+        qemu_cond_signal(&multifd->load_bufs_iter_done_cond);
+    }
+    bql_lock();
+
+    if (ret) {
+        error_report("%s: duplicate DEV_CONFIG_LOAD_READY",
+                     vbasedev->name);
+    }
+
+    return ret;
+}
+
 static VFIOMultifd *vfio_multifd_new(void)
 {
     VFIOMultifd *multifd = g_new(VFIOMultifd, 1);
@@ -422,8 +512,12 @@ static VFIOMultifd *vfio_multifd_new(void)
 
     multifd->load_buf_idx = 0;
     multifd->load_buf_idx_last = UINT32_MAX;
+    multifd->load_buf_queued_pending_buffers_size = 0;
     qemu_cond_init(&multifd->load_bufs_buffer_ready_cond);
 
+    multifd->load_bufs_iter_done = false;
+    qemu_cond_init(&multifd->load_bufs_iter_done_cond);
+
     multifd->load_bufs_thread_running = false;
     multifd->load_bufs_thread_want_exit = false;
     qemu_cond_init(&multifd->load_bufs_thread_finished_cond);
@@ -447,6 +541,7 @@ static void vfio_load_cleanup_load_bufs_thread(VFIOMultifd *multifd)
             multifd->load_bufs_thread_want_exit = true;
 
             qemu_cond_signal(&multifd->load_bufs_buffer_ready_cond);
+            qemu_cond_signal(&multifd->load_bufs_iter_done_cond);
             qemu_cond_wait(&multifd->load_bufs_thread_finished_cond,
                            &multifd->load_bufs_mutex);
         }
@@ -459,6 +554,7 @@ static void vfio_multifd_free(VFIOMultifd *multifd)
     vfio_load_cleanup_load_bufs_thread(multifd);
 
     qemu_cond_destroy(&multifd->load_bufs_thread_finished_cond);
+    qemu_cond_destroy(&multifd->load_bufs_iter_done_cond);
     vfio_state_buffers_destroy(&multifd->load_bufs);
     qemu_cond_destroy(&multifd->load_bufs_buffer_ready_cond);
     qemu_mutex_destroy(&multifd->load_bufs_mutex);
diff --git a/hw/vfio/migration-multifd.h b/hw/vfio/migration-multifd.h
index ebf22a7997..82d2d3a1fd 100644
--- a/hw/vfio/migration-multifd.h
+++ b/hw/vfio/migration-multifd.h
@@ -20,9 +20,12 @@ void vfio_multifd_cleanup(VFIODevice *vbasedev);
 bool vfio_multifd_transfer_supported(void);
 bool vfio_multifd_transfer_enabled(VFIODevice *vbasedev);
 
+bool vfio_load_config_after_iter(VFIODevice *vbasedev);
 bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size,
                                     Error **errp);
 
+int vfio_load_state_config_load_ready(VFIODevice *vbasedev);
+
 void vfio_multifd_emit_dummy_eos(VFIODevice *vbasedev, QEMUFile *f);
 
 bool
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index c329578eec..4c06e3db93 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -675,7 +675,11 @@ static void vfio_save_state(QEMUFile *f, void *opaque)
     int ret;
 
     if (vfio_multifd_transfer_enabled(vbasedev)) {
-        vfio_multifd_emit_dummy_eos(vbasedev, f);
+        if (vfio_load_config_after_iter(vbasedev)) {
+            qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY);
+        } else {
+            vfio_multifd_emit_dummy_eos(vbasedev, f);
+        }
         return;
     }
 
@@ -784,6 +788,10 @@ static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
 
             return ret;
         }
+        case VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY:
+        {
+            return vfio_load_state_config_load_ready(vbasedev);
+        }
         default:
             error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data);
             return -EINVAL;
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 1093b28df7..be05002b98 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2893,10 +2893,6 @@ bool vfio_populate_vga(VFIOPCIDevice *vdev, Error **errp)
                           "vfio-vga-io@0x3c0",
                           QEMU_PCI_VGA_IO_HI_SIZE);
 
-    pci_register_vga(&vdev->pdev, &vdev->vga->region[QEMU_PCI_VGA_MEM].mem,
-                     &vdev->vga->region[QEMU_PCI_VGA_IO_LO].mem,
-                     &vdev->vga->region[QEMU_PCI_VGA_IO_HI].mem);
-
     return true;
 }
 
@@ -3228,6 +3224,23 @@ bool vfio_pci_config_setup(VFIOPCIDevice *vdev, Error **errp)
                                               vdev->sub_device_id);
     }
 
+    /*
+     * Class code is a 24-bit value at config space 0x09. Allow overriding it
+     * with any 24-bit value.
+     */
+    if (vdev->class_code != PCI_ANY_ID) {
+        if (vdev->class_code > 0xffffff) {
+            error_setg(errp, "invalid PCI class code provided");
+            return false;
+        }
+        /* Higher 24 bits of PCI_CLASS_REVISION are class code */
+        vfio_add_emulated_long(vdev, PCI_CLASS_REVISION,
+                               vdev->class_code << 8, ~0xff);
+        trace_vfio_pci_emulated_class_code(vbasedev->name, vdev->class_code);
+    } else {
+        vdev->class_code = pci_get_long(pdev->config + PCI_CLASS_REVISION) >> 8;
+    }
+
     /* QEMU can change multi-function devices to single function, or reverse */
     vdev->emulated_config_bits[PCI_HEADER_TYPE] =
                                               PCI_HEADER_TYPE_MULTI_FUNCTION;
@@ -3257,6 +3270,12 @@ bool vfio_pci_config_setup(VFIOPCIDevice *vdev, Error **errp)
 
     vfio_bars_register(vdev);
 
+    if (vdev->vga && vfio_is_vga(vdev)) {
+        pci_register_vga(&vdev->pdev, &vdev->vga->region[QEMU_PCI_VGA_MEM].mem,
+                         &vdev->vga->region[QEMU_PCI_VGA_IO_LO].mem,
+                         &vdev->vga->region[QEMU_PCI_VGA_IO_HI].mem);
+    }
+
     return true;
 }
 
@@ -3623,6 +3642,11 @@ static const Property vfio_pci_dev_properties[] = {
                 vbasedev.migration_multifd_transfer,
                 vfio_pci_migration_multifd_transfer_prop, OnOffAuto,
                 .set_default = true, .defval.i = ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_ON_OFF_AUTO("x-migration-load-config-after-iter", VFIOPCIDevice,
+                            vbasedev.migration_load_config_after_iter,
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_SIZE("x-migration-max-queued-buffers-size", VFIOPCIDevice,
+                     vbasedev.migration_max_queued_buffers_size, UINT64_MAX),
     DEFINE_PROP_BOOL("migration-events", VFIOPCIDevice,
                      vbasedev.migration_events, false),
     DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false),
@@ -3643,6 +3667,8 @@ static const Property vfio_pci_dev_properties[] = {
                        sub_vendor_id, PCI_ANY_ID),
     DEFINE_PROP_UINT32("x-pci-sub-device-id", VFIOPCIDevice,
                        sub_device_id, PCI_ANY_ID),
+    DEFINE_PROP_UINT32("x-pci-class-code", VFIOPCIDevice,
+                       class_code, PCI_ANY_ID),
     DEFINE_PROP_UINT32("x-igd-gms", VFIOPCIDevice, igd_gms, 0),
     DEFINE_PROP_UNSIGNED_NODEFAULT("x-nv-gpudirect-clique", VFIOPCIDevice,
                                    nv_gpudirect_clique,
@@ -3797,6 +3823,20 @@ static void vfio_pci_dev_class_init(ObjectClass *klass, const void *data)
                                           "x-migration-multifd-transfer",
                                           "Transfer this device state via "
                                           "multifd channels when live migrating it");
+    object_class_property_set_description(klass, /* 10.1 */
+                                          "x-migration-load-config-after-iter",
+                                          "Start the config load only after "
+                                          "all iterables were loaded (during "
+                                          "non-iterables loading phase) when "
+                                          "doing live migration of device state "
+                                          "via multifd channels");
+    object_class_property_set_description(klass, /* 10.1 */
+                                          "x-migration-max-queued-buffers-size",
+                                          "Maximum size of in-flight VFIO "
+                                          "device state buffers queued at the "
+                                          "destination when doing live "
+                                          "migration of device state via "
+                                          "multifd channels");
 }
 
 static const TypeInfo vfio_pci_dev_info = {
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index 495fae737d..4aa6461117 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -157,6 +157,7 @@ struct VFIOPCIDevice {
     uint32_t device_id;
     uint32_t sub_vendor_id;
     uint32_t sub_device_id;
+    uint32_t class_code;
     uint32_t features;
 #define VFIO_FEATURE_ENABLE_VGA_BIT 0
 #define VFIO_FEATURE_ENABLE_VGA (1 << VFIO_FEATURE_ENABLE_VGA_BIT)
@@ -205,10 +206,7 @@ static inline bool vfio_pci_is(VFIOPCIDevice *vdev, uint32_t vendor, uint32_t de
 
 static inline bool vfio_is_vga(VFIOPCIDevice *vdev)
 {
-    PCIDevice *pdev = &vdev->pdev;
-    uint16_t class = pci_get_word(pdev->config + PCI_CLASS_DEVICE);
-
-    return class == PCI_CLASS_DISPLAY_VGA;
+    return (vdev->class_code >> 8) == PCI_CLASS_DISPLAY_VGA;
 }
 
 /* MSI/MSI-X/INTx */
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index 8ec0ad0cde..fc6ed230d0 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -48,6 +48,7 @@ vfio_pci_emulated_vendor_id(const char *name, uint16_t val) "%s 0x%04x"
 vfio_pci_emulated_device_id(const char *name, uint16_t val) "%s 0x%04x"
 vfio_pci_emulated_sub_vendor_id(const char *name, uint16_t val) "%s 0x%04x"
 vfio_pci_emulated_sub_device_id(const char *name, uint16_t val) "%s 0x%04x"
+vfio_pci_emulated_class_code(const char *name, uint32_t val) "%s 0x%06x"
 
 # pci-quirks.c
 vfio_quirk_rom_in_denylist(const char *name, uint16_t vid, uint16_t did) "%s %04x:%04x"
diff --git a/hw/vfio/vfio-helpers.h b/hw/vfio/vfio-helpers.h
index 54a327ffbc..ce31758080 100644
--- a/hw/vfio/vfio-helpers.h
+++ b/hw/vfio/vfio-helpers.h
@@ -32,4 +32,6 @@ struct vfio_device_info *vfio_get_device_info(int fd);
 int vfio_kvm_device_add_fd(int fd, Error **errp);
 int vfio_kvm_device_del_fd(int fd, Error **errp);
 
+bool vfio_arch_wants_loading_config_after_iter(void);
+
 #endif /* HW_VFIO_VFIO_HELPERS_H */
diff --git a/hw/vfio/vfio-migration-internal.h b/hw/vfio/vfio-migration-internal.h
index a8b456b239..54141e27e6 100644
--- a/hw/vfio/vfio-migration-internal.h
+++ b/hw/vfio/vfio-migration-internal.h
@@ -32,6 +32,7 @@
 #define VFIO_MIG_FLAG_DEV_SETUP_STATE   (0xffffffffef100003ULL)
 #define VFIO_MIG_FLAG_DEV_DATA_STATE    (0xffffffffef100004ULL)
 #define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL)
+#define VFIO_MIG_FLAG_DEV_CONFIG_LOAD_READY (0xffffffffef100006ULL)
 
 typedef struct VFIODevice VFIODevice;
 typedef struct VFIOMultifd VFIOMultifd;
diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
index 1901a35aa9..6e4d5ccdac 100644
--- a/include/hw/vfio/vfio-device.h
+++ b/include/hw/vfio/vfio-device.h
@@ -67,6 +67,8 @@ typedef struct VFIODevice {
     bool ram_block_discard_allowed;
     OnOffAuto enable_migration;
     OnOffAuto migration_multifd_transfer;
+    OnOffAuto migration_load_config_after_iter;
+    uint64_t migration_max_queued_buffers_size;
     bool migration_events;
     bool use_region_fds;
     VFIODeviceOps *ops;