vhost: use avail event idx on vhost_svq_kick

So SVQ code knows if an event is needed.

The code is not reachable at the moment.

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Eugenio Pérez 2022-10-20 17:52:50 +02:00 committed by Jason Wang
parent 01f8beacea
commit 22a6840ff2

View File

@ -218,12 +218,22 @@ static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
static void vhost_svq_kick(VhostShadowVirtqueue *svq)
{
bool needs_kick;
/*
* We need to expose the available array entries before checking the used
* flags
*/
smp_mb();
if (svq->vring.used->flags & VRING_USED_F_NO_NOTIFY) {
if (virtio_vdev_has_feature(svq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
uint16_t avail_event = *(uint16_t *)(&svq->vring.used->ring[svq->vring.num]);
needs_kick = vring_need_event(avail_event, svq->shadow_avail_idx, svq->shadow_avail_idx - 1);
} else {
needs_kick = !(svq->vring.used->flags & VRING_USED_F_NO_NOTIFY);
}
if (!needs_kick) {
return;
}