diff options
Diffstat (limited to 'hw/virtio-pci.c')
| -rw-r--r-- | hw/virtio-pci.c | 213 |
1 files changed, 184 insertions, 29 deletions
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c index 6186142b2b..d07ff976be 100644 --- a/hw/virtio-pci.c +++ b/hw/virtio-pci.c @@ -80,9 +80,13 @@ * 12 is historical, and due to x86 page size. */ #define VIRTIO_PCI_QUEUE_ADDR_SHIFT 12 -/* We can catch some guest bugs inside here so we continue supporting older - guests. */ -#define VIRTIO_PCI_BUG_BUS_MASTER (1 << 0) +/* Flags track per-device state like workarounds for quirks in older guests. */ +#define VIRTIO_PCI_FLAG_BUS_MASTER_BUG (1 << 0) + +/* Performance improves when virtqueue kick processing is decoupled from the + * vcpu thread using ioeventfd for some devices. */ +#define VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT 1 +#define VIRTIO_PCI_FLAG_USE_IOEVENTFD (1 << VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT) /* QEMU doesn't strictly need write barriers since everything runs in * lock-step. We'll leave the calls to wmb() in though to make it obvious for @@ -95,7 +99,7 @@ typedef struct { PCIDevice pci_dev; VirtIODevice *vdev; - uint32_t bugs; + uint32_t flags; uint32_t addr; uint32_t class_code; uint32_t nvectors; @@ -108,6 +112,8 @@ typedef struct { /* Max. number of ports we can have for a the virtio-serial device */ uint32_t max_virtserial_ports; virtio_net_conf net; + bool ioeventfd_disabled; + bool ioeventfd_started; } VirtIOPCIProxy; /* virtio device */ @@ -159,7 +165,7 @@ static int virtio_pci_load_config(void * opaque, QEMUFile *f) in ready state. Then we have a buggy guest OS. */ if ((proxy->vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) && !(proxy->pci_dev.config[PCI_COMMAND] & PCI_COMMAND_MASTER)) { - proxy->bugs |= VIRTIO_PCI_BUG_BUS_MASTER; + proxy->flags |= VIRTIO_PCI_FLAG_BUS_MASTER_BUG; } return 0; } @@ -180,12 +186,139 @@ static int virtio_pci_load_queue(void * opaque, int n, QEMUFile *f) return 0; } +static int virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy, + int n, bool assign) +{ + VirtQueue *vq = virtio_get_queue(proxy->vdev, n); + EventNotifier *notifier = virtio_queue_get_host_notifier(vq); + int r; + if (assign) { + r = event_notifier_init(notifier, 1); + if (r < 0) { + error_report("%s: unable to init event notifier: %d", + __func__, r); + return r; + } + r = kvm_set_ioeventfd_pio_word(event_notifier_get_fd(notifier), + proxy->addr + VIRTIO_PCI_QUEUE_NOTIFY, + n, assign); + if (r < 0) { + error_report("%s: unable to map ioeventfd: %d", + __func__, r); + event_notifier_cleanup(notifier); + } + } else { + r = kvm_set_ioeventfd_pio_word(event_notifier_get_fd(notifier), + proxy->addr + VIRTIO_PCI_QUEUE_NOTIFY, + n, assign); + if (r < 0) { + error_report("%s: unable to unmap ioeventfd: %d", + __func__, r); + return r; + } + + /* Handle the race condition where the guest kicked and we deassigned + * before we got around to handling the kick. + */ + if (event_notifier_test_and_clear(notifier)) { + virtio_queue_notify_vq(vq); + } + + event_notifier_cleanup(notifier); + } + return r; +} + +static void virtio_pci_host_notifier_read(void *opaque) +{ + VirtQueue *vq = opaque; + EventNotifier *n = virtio_queue_get_host_notifier(vq); + if (event_notifier_test_and_clear(n)) { + virtio_queue_notify_vq(vq); + } +} + +static void virtio_pci_set_host_notifier_fd_handler(VirtIOPCIProxy *proxy, + int n, bool assign) +{ + VirtQueue *vq = virtio_get_queue(proxy->vdev, n); + EventNotifier *notifier = virtio_queue_get_host_notifier(vq); + if (assign) { + qemu_set_fd_handler(event_notifier_get_fd(notifier), + virtio_pci_host_notifier_read, NULL, vq); + } else { + qemu_set_fd_handler(event_notifier_get_fd(notifier), + NULL, NULL, NULL); + } +} + +static void virtio_pci_start_ioeventfd(VirtIOPCIProxy *proxy) +{ + int n, r; + + if (!(proxy->flags & VIRTIO_PCI_FLAG_USE_IOEVENTFD) || + proxy->ioeventfd_disabled || + proxy->ioeventfd_started) { + return; + } + + for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) { + if (!virtio_queue_get_num(proxy->vdev, n)) { + continue; + } + + r = virtio_pci_set_host_notifier_internal(proxy, n, true); + if (r < 0) { + goto assign_error; + } + + virtio_pci_set_host_notifier_fd_handler(proxy, n, true); + } + proxy->ioeventfd_started = true; + return; + +assign_error: + while (--n >= 0) { + if (!virtio_queue_get_num(proxy->vdev, n)) { + continue; + } + + virtio_pci_set_host_notifier_fd_handler(proxy, n, false); + r = virtio_pci_set_host_notifier_internal(proxy, n, false); + assert(r >= 0); + } + proxy->ioeventfd_started = false; + error_report("%s: failed. Fallback to a userspace (slower).", __func__); +} + +static void virtio_pci_stop_ioeventfd(VirtIOPCIProxy *proxy) +{ + int r; + int n; + + if (!proxy->ioeventfd_started) { + return; + } + + for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) { + if (!virtio_queue_get_num(proxy->vdev, n)) { + continue; + } + + virtio_pci_set_host_notifier_fd_handler(proxy, n, false); + r = virtio_pci_set_host_notifier_internal(proxy, n, false); + assert(r >= 0); + } + proxy->ioeventfd_started = false; +} + static void virtio_pci_reset(DeviceState *d) { VirtIOPCIProxy *proxy = container_of(d, VirtIOPCIProxy, pci_dev.qdev); + virtio_pci_stop_ioeventfd(proxy); virtio_reset(proxy->vdev); msix_reset(&proxy->pci_dev); - proxy->bugs = 0; + proxy->flags &= ~VIRTIO_PCI_FLAG_BUS_MASTER_BUG; } static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val) @@ -210,6 +343,7 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val) case VIRTIO_PCI_QUEUE_PFN: pa = (target_phys_addr_t)val << VIRTIO_PCI_QUEUE_ADDR_SHIFT; if (pa == 0) { + virtio_pci_stop_ioeventfd(proxy); virtio_reset(proxy->vdev); msix_unuse_all_vectors(&proxy->pci_dev); } @@ -224,7 +358,16 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val) virtio_queue_notify(vdev, val); break; case VIRTIO_PCI_STATUS: + if (!(val & VIRTIO_CONFIG_S_DRIVER_OK)) { + virtio_pci_stop_ioeventfd(proxy); + } + virtio_set_status(vdev, val & 0xFF); + + if (val & VIRTIO_CONFIG_S_DRIVER_OK) { + virtio_pci_start_ioeventfd(proxy); + } + if (vdev->status == 0) { virtio_reset(proxy->vdev); msix_unuse_all_vectors(&proxy->pci_dev); @@ -235,7 +378,7 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val) some safety checks. */ if ((val & VIRTIO_CONFIG_S_DRIVER_OK) && !(proxy->pci_dev.config[PCI_COMMAND] & PCI_COMMAND_MASTER)) { - proxy->bugs |= VIRTIO_PCI_BUG_BUS_MASTER; + proxy->flags |= VIRTIO_PCI_FLAG_BUS_MASTER_BUG; } break; case VIRTIO_MSI_CONFIG_VECTOR: @@ -403,7 +546,8 @@ static void virtio_write_config(PCIDevice *pci_dev, uint32_t address, if (PCI_COMMAND == address) { if (!(val & PCI_COMMAND_MASTER)) { - if (!(proxy->bugs & VIRTIO_PCI_BUG_BUS_MASTER)) { + if (!(proxy->flags & VIRTIO_PCI_FLAG_BUS_MASTER_BUG)) { + virtio_pci_stop_ioeventfd(proxy); virtio_set_status(proxy->vdev, proxy->vdev->status & ~VIRTIO_CONFIG_S_DRIVER_OK); } @@ -481,30 +625,30 @@ assign_error: static int virtio_pci_set_host_notifier(void *opaque, int n, bool assign) { VirtIOPCIProxy *proxy = opaque; - VirtQueue *vq = virtio_get_queue(proxy->vdev, n); - EventNotifier *notifier = virtio_queue_get_host_notifier(vq); - int r; + + /* Stop using ioeventfd for virtqueue kick if the device starts using host + * notifiers. This makes it easy to avoid stepping on each others' toes. + */ + proxy->ioeventfd_disabled = assign; if (assign) { - r = event_notifier_init(notifier, 1); - if (r < 0) { - return r; - } - r = kvm_set_ioeventfd_pio_word(event_notifier_get_fd(notifier), - proxy->addr + VIRTIO_PCI_QUEUE_NOTIFY, - n, assign); - if (r < 0) { - event_notifier_cleanup(notifier); - } + virtio_pci_stop_ioeventfd(proxy); + } + /* We don't need to start here: it's not needed because backend + * currently only stops on status change away from ok, + * reset, vmstop and such. If we do add code to start here, + * need to check vmstate, device state etc. */ + return virtio_pci_set_host_notifier_internal(proxy, n, assign); +} + +static void virtio_pci_vmstate_change(void *opaque, bool running) +{ + VirtIOPCIProxy *proxy = opaque; + + if (running) { + virtio_pci_start_ioeventfd(proxy); } else { - r = kvm_set_ioeventfd_pio_word(event_notifier_get_fd(notifier), - proxy->addr + VIRTIO_PCI_QUEUE_NOTIFY, - n, assign); - if (r < 0) { - return r; - } - event_notifier_cleanup(notifier); + virtio_pci_stop_ioeventfd(proxy); } - return r; } static const VirtIOBindings virtio_pci_bindings = { @@ -516,6 +660,7 @@ static const VirtIOBindings virtio_pci_bindings = { .get_features = virtio_pci_get_features, .set_host_notifier = virtio_pci_set_host_notifier, .set_guest_notifiers = virtio_pci_set_guest_notifiers, + .vmstate_change = virtio_pci_vmstate_change, }; static void virtio_init_pci(VirtIOPCIProxy *proxy, VirtIODevice *vdev, @@ -560,6 +705,10 @@ static void virtio_init_pci(VirtIOPCIProxy *proxy, VirtIODevice *vdev, pci_register_bar(&proxy->pci_dev, 0, size, PCI_BASE_ADDRESS_SPACE_IO, virtio_map); + if (!kvm_has_many_ioeventfds()) { + proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD; + } + virtio_bind_device(vdev, &virtio_pci_bindings, proxy); proxy->host_features |= 0x1 << VIRTIO_F_NOTIFY_ON_EMPTY; proxy->host_features |= 0x1 << VIRTIO_F_BAD_FEATURE; @@ -598,6 +747,7 @@ static int virtio_blk_exit_pci(PCIDevice *pci_dev) { VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev); + virtio_pci_stop_ioeventfd(proxy); virtio_blk_exit(proxy->vdev); blockdev_mark_auto_del(proxy->block.bs); return virtio_exit_pci(pci_dev); @@ -659,6 +809,7 @@ static int virtio_net_exit_pci(PCIDevice *pci_dev) { VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev); + virtio_pci_stop_ioeventfd(proxy); virtio_net_exit(proxy->vdev); return virtio_exit_pci(pci_dev); } @@ -706,6 +857,8 @@ static PCIDeviceInfo virtio_info[] = { .qdev.props = (Property[]) { DEFINE_PROP_HEX32("class", VirtIOPCIProxy, class_code, 0), DEFINE_BLOCK_PROPERTIES(VirtIOPCIProxy, block), + DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags, + VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true), DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2), DEFINE_VIRTIO_BLK_FEATURES(VirtIOPCIProxy, host_features), DEFINE_PROP_END_OF_LIST(), @@ -718,6 +871,8 @@ static PCIDeviceInfo virtio_info[] = { .exit = virtio_net_exit_pci, .romfile = "pxe-virtio.bin", .qdev.props = (Property[]) { + DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags, + VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, false), DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 3), DEFINE_VIRTIO_NET_FEATURES(VirtIOPCIProxy, host_features), DEFINE_NIC_PROPERTIES(VirtIOPCIProxy, nic), |