diff options
Diffstat (limited to 'hw/virtio/virtio-bus.c')
-rw-r--r-- | hw/virtio/virtio-bus.c | 154 |
1 files changed, 60 insertions, 94 deletions
diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c index 11f65bd..bf61f66 100644 --- a/hw/virtio/virtio-bus.c +++ b/hw/virtio/virtio-bus.c @@ -147,131 +147,97 @@ void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config) } } -/* - * This function handles both assigning the ioeventfd handler and - * registering it with the kernel. - * assign: register/deregister ioeventfd with the kernel - * set_handler: use the generic ioeventfd handler - */ -static int set_host_notifier_internal(DeviceState *proxy, VirtioBusState *bus, - int n, bool assign, bool set_handler) +int virtio_bus_start_ioeventfd(VirtioBusState *bus) { - VirtIODevice *vdev = virtio_bus_get_device(bus); VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus); - VirtQueue *vq = virtio_get_queue(vdev, n); - EventNotifier *notifier = virtio_queue_get_host_notifier(vq); - int r = 0; + DeviceState *proxy = DEVICE(BUS(bus)->parent); + VirtIODevice *vdev = virtio_bus_get_device(bus); + VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev); + int r; - if (assign) { - r = event_notifier_init(notifier, 1); - if (r < 0) { - error_report("%s: unable to init event notifier: %s (%d)", - __func__, strerror(-r), r); - return r; - } - virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler); - r = k->ioeventfd_assign(proxy, notifier, n, assign); - if (r < 0) { - error_report("%s: unable to assign ioeventfd: %d", __func__, r); - virtio_queue_set_host_notifier_fd_handler(vq, false, false); - event_notifier_cleanup(notifier); - return r; - } - } else { - k->ioeventfd_assign(proxy, notifier, n, assign); - virtio_queue_set_host_notifier_fd_handler(vq, false, false); - event_notifier_cleanup(notifier); + if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) { + return -ENOSYS; } - return r; + if (bus->ioeventfd_started) { + return 0; + } + r = vdc->start_ioeventfd(vdev); + if (r < 0) { + error_report("%s: failed. Fallback to userspace (slower).", __func__); + return r; + } + bus->ioeventfd_started = true; + return 0; } -void virtio_bus_start_ioeventfd(VirtioBusState *bus) +void virtio_bus_stop_ioeventfd(VirtioBusState *bus) { - VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus); - DeviceState *proxy = DEVICE(BUS(bus)->parent); VirtIODevice *vdev; - int n, r; + VirtioDeviceClass *vdc; - if (!k->ioeventfd_started || k->ioeventfd_started(proxy)) { + if (!bus->ioeventfd_started) { return; } - if (k->ioeventfd_disabled(proxy)) { - return; - } - vdev = virtio_bus_get_device(bus); - for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { - if (!virtio_queue_get_num(vdev, n)) { - continue; - } - r = set_host_notifier_internal(proxy, bus, n, true, true); - if (r < 0) { - goto assign_error; - } - } - k->ioeventfd_set_started(proxy, true, false); - return; - -assign_error: - while (--n >= 0) { - if (!virtio_queue_get_num(vdev, n)) { - continue; - } - r = set_host_notifier_internal(proxy, bus, n, false, false); - assert(r >= 0); - } - k->ioeventfd_set_started(proxy, false, true); - error_report("%s: failed. Fallback to userspace (slower).", __func__); + vdev = virtio_bus_get_device(bus); + vdc = VIRTIO_DEVICE_GET_CLASS(vdev); + vdc->stop_ioeventfd(vdev); + bus->ioeventfd_started = false; } -void virtio_bus_stop_ioeventfd(VirtioBusState *bus) +bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus) { VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus); DeviceState *proxy = DEVICE(BUS(bus)->parent); - VirtIODevice *vdev; - int n, r; - if (!k->ioeventfd_started || !k->ioeventfd_started(proxy)) { - return; - } - vdev = virtio_bus_get_device(bus); - for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { - if (!virtio_queue_get_num(vdev, n)) { - continue; - } - r = set_host_notifier_internal(proxy, bus, n, false, false); - assert(r >= 0); - } - k->ioeventfd_set_started(proxy, false, false); + return k->ioeventfd_assign && k->ioeventfd_enabled(proxy); } /* - * This function switches from/to the generic ioeventfd handler. - * assign==false means 'use generic ioeventfd handler'. + * This function switches ioeventfd on/off in the device. + * The caller must set or clear the handlers for the EventNotifier. */ int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign) { + VirtIODevice *vdev = virtio_bus_get_device(bus); VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus); DeviceState *proxy = DEVICE(BUS(bus)->parent); + VirtQueue *vq = virtio_get_queue(vdev, n); + EventNotifier *notifier = virtio_queue_get_host_notifier(vq); + int r = 0; - if (!k->ioeventfd_started) { + if (!k->ioeventfd_assign) { return -ENOSYS; } - k->ioeventfd_set_disabled(proxy, assign); + if (assign) { - /* - * Stop using the generic ioeventfd, we are doing eventfd handling - * ourselves below - * - * FIXME: We should just switch the handler and not deassign the - * ioeventfd. - * Otherwise, there's a window where we don't have an - * ioeventfd and we may end up with a notification where - * we don't expect one. - */ - virtio_bus_stop_ioeventfd(bus); + assert(!bus->ioeventfd_started); + r = event_notifier_init(notifier, 1); + if (r < 0) { + error_report("%s: unable to init event notifier: %s (%d)", + __func__, strerror(-r), r); + return r; + } + r = k->ioeventfd_assign(proxy, notifier, n, true); + if (r < 0) { + error_report("%s: unable to assign ioeventfd: %d", __func__, r); + goto cleanup_event_notifier; + } + return 0; + } else { + if (!bus->ioeventfd_started) { + return 0; + } + k->ioeventfd_assign(proxy, notifier, n, false); } - return set_host_notifier_internal(proxy, bus, n, assign, false); + +cleanup_event_notifier: + /* Test and clear notifier after disabling event, + * in case poll callback didn't have time to run. + */ + virtio_queue_host_notifier_read(notifier); + event_notifier_cleanup(notifier); + return r; } static char *virtio_bus_get_dev_path(DeviceState *dev) |