diff options
| -rw-r--r-- | hw/virtio/virtio.c | 38 | ||||
| -rw-r--r-- | include/hw/virtio/virtio.h | 1 |
2 files changed, 39 insertions, 0 deletions
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index baffff703f..aa4f38f50a 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -783,6 +783,44 @@ err_undo_map: return NULL; } +/* virtqueue_drop_all: + * @vq: The #VirtQueue + * Drops all queued buffers and indicates them to the guest + * as if they are done. Useful when buffers can not be + * processed but must be returned to the guest. + */ +unsigned int virtqueue_drop_all(VirtQueue *vq) +{ + unsigned int dropped = 0; + VirtQueueElement elem = {}; + VirtIODevice *vdev = vq->vdev; + bool fEventIdx = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); + + if (unlikely(vdev->broken)) { + return 0; + } + + while (!virtio_queue_empty(vq) && vq->inuse < vq->vring.num) { + /* works similar to virtqueue_pop but does not map buffers + * and does not allocate any memory */ + smp_rmb(); + if (!virtqueue_get_head(vq, vq->last_avail_idx, &elem.index)) { + break; + } + vq->inuse++; + vq->last_avail_idx++; + if (fEventIdx) { + vring_set_avail_event(vq, vq->last_avail_idx); + } + /* immediately push the element, nothing to unmap + * as both in_num and out_num are set to 0 */ + virtqueue_push(vq, &elem, 0); + dropped++; + } + + return dropped; +} + /* Reading and writing a structure directly to QEMUFile is *awful*, but * it is what QEMU has always done by mistake. We can change it sooner * or later by bumping the version number of the affected vm states. diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index e15c06489b..e5541c61f7 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -173,6 +173,7 @@ void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem); void *virtqueue_pop(VirtQueue *vq, size_t sz); +unsigned int virtqueue_drop_all(VirtQueue *vq); void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz); void qemu_put_virtqueue_element(QEMUFile *f, VirtQueueElement *elem); int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes, |