diff options
| -rw-r--r-- | hw/net/virtio-net.c | 28 | ||||
| -rw-r--r-- | hw/virtio/virtio.c | 64 | ||||
| -rw-r--r-- | include/hw/virtio/virtio.h | 19 |
3 files changed, 92 insertions, 19 deletions
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 5635620a31..08aa0b65e3 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -1641,24 +1641,28 @@ static bool virtio_net_can_receive(NetClientState *nc) static int virtio_net_has_buffers(VirtIONetQueue *q, int bufsize) { + int opaque; + unsigned int in_bytes; VirtIONet *n = q->n; - if (virtio_queue_empty(q->rx_vq) || - (n->mergeable_rx_bufs && - !virtqueue_avail_bytes(q->rx_vq, bufsize, 0))) { - virtio_queue_set_notification(q->rx_vq, 1); - - /* To avoid a race condition where the guest has made some buffers - * available after the above check but before notification was - * enabled, check for available buffers again. - */ - if (virtio_queue_empty(q->rx_vq) || - (n->mergeable_rx_bufs && - !virtqueue_avail_bytes(q->rx_vq, bufsize, 0))) { + + while (virtio_queue_empty(q->rx_vq) || n->mergeable_rx_bufs) { + opaque = virtqueue_get_avail_bytes(q->rx_vq, &in_bytes, NULL, + bufsize, 0); + /* Buffer is enough, disable notifiaction */ + if (bufsize <= in_bytes) { + break; + } + + if (virtio_queue_enable_notification_and_check(q->rx_vq, opaque)) { + /* Guest has added some buffers, try again */ + continue; + } else { return 0; } } virtio_queue_set_notification(q->rx_vq, 0); + return 1; } diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 397c261c3c..9e10cbc058 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -744,6 +744,60 @@ int virtio_queue_empty(VirtQueue *vq) } } +static bool virtio_queue_split_poll(VirtQueue *vq, unsigned shadow_idx) +{ + if (unlikely(!vq->vring.avail)) { + return false; + } + + return (uint16_t)shadow_idx != vring_avail_idx(vq); +} + +static bool virtio_queue_packed_poll(VirtQueue *vq, unsigned shadow_idx) +{ + VRingPackedDesc desc; + VRingMemoryRegionCaches *caches; + + if (unlikely(!vq->vring.desc)) { + return false; + } + + caches = vring_get_region_caches(vq); + if (!caches) { + return false; + } + + vring_packed_desc_read(vq->vdev, &desc, &caches->desc, + shadow_idx, true); + + return is_desc_avail(desc.flags, vq->shadow_avail_wrap_counter); +} + +static bool virtio_queue_poll(VirtQueue *vq, unsigned shadow_idx) +{ + if (virtio_device_disabled(vq->vdev)) { + return false; + } + + if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { + return virtio_queue_packed_poll(vq, shadow_idx); + } else { + return virtio_queue_split_poll(vq, shadow_idx); + } +} + +bool virtio_queue_enable_notification_and_check(VirtQueue *vq, + int opaque) +{ + virtio_queue_set_notification(vq, 1); + + if (opaque >= 0) { + return virtio_queue_poll(vq, (unsigned)opaque); + } else { + return false; + } +} + static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len) { @@ -1442,9 +1496,9 @@ err: goto done; } -void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, - unsigned int *out_bytes, - unsigned max_in_bytes, unsigned max_out_bytes) +int virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, + unsigned int *out_bytes, unsigned max_in_bytes, + unsigned max_out_bytes) { uint16_t desc_size; VRingMemoryRegionCaches *caches; @@ -1477,7 +1531,7 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, caches); } - return; + return (int)vq->shadow_avail_idx; err: if (in_bytes) { *in_bytes = 0; @@ -1485,6 +1539,8 @@ err: if (out_bytes) { *out_bytes = 0; } + + return -1; } int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes, diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index d2a1938757..0fcbc5c0c6 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -273,9 +273,13 @@ void qemu_put_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, VirtQueueElement *elem); int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes, unsigned int out_bytes); -void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, - unsigned int *out_bytes, - unsigned max_in_bytes, unsigned max_out_bytes); +/** + * Return <0 on error or an opaque >=0 to pass to + * virtio_queue_enable_notification_and_check on success. + */ +int virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, + unsigned int *out_bytes, unsigned max_in_bytes, + unsigned max_out_bytes); void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq); void virtio_notify(VirtIODevice *vdev, VirtQueue *vq); @@ -309,6 +313,15 @@ int virtio_queue_ready(VirtQueue *vq); int virtio_queue_empty(VirtQueue *vq); +/** + * Enable notification and check whether guest has added some + * buffers since last call to virtqueue_get_avail_bytes. + * + * @opaque: value returned from virtqueue_get_avail_bytes + */ +bool virtio_queue_enable_notification_and_check(VirtQueue *vq, + int opaque); + void virtio_queue_set_shadow_avail_idx(VirtQueue *vq, uint16_t idx); /* Host binding interface. */ |