vhost: Always store new kick fd on vhost_svq_set_svq_kick_fd

We can unbind twice a file descriptor if we call twice
vhost_svq_set_svq_kick_fd because of this. Since it comes from vhost and
not from SVQ, that file descriptor could be a different thing that
guest's vhost notifier.

Likewise, it can happens the same if a guest start and stop the device
multiple times.

Reported-by: Lei Yang <leiyang@redhat.com>
Fixes: dff4426fa6 ("vhost: Add Shadow VirtQueue kick forwarding capabilities")
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Eugenio Pérez 2022-08-23 20:20:07 +02:00 committed by Jason Wang
parent 5b590f51b9
commit 8b64e48642

View File

@ -602,13 +602,13 @@ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd)
event_notifier_set_handler(svq_kick, NULL);
}
event_notifier_init_fd(svq_kick, svq_kick_fd);
/*
* event_notifier_set_handler already checks for guest's notifications if
* they arrive at the new file descriptor in the switch, so there is no
* need to explicitly check for them.
*/
if (poll_start) {
event_notifier_init_fd(svq_kick, svq_kick_fd);
event_notifier_set(svq_kick);
event_notifier_set_handler(svq_kick, vhost_handle_guest_kick_notifier);
}
@ -655,7 +655,7 @@ void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
*/
void vhost_svq_stop(VhostShadowVirtqueue *svq)
{
event_notifier_set_handler(&svq->svq_kick, NULL);
vhost_svq_set_svq_kick_fd(svq, VHOST_FILE_UNBIND);
g_autofree VirtQueueElement *next_avail_elem = NULL;
if (!svq->vq) {