[PATCH v3 3/4] vhost: fix invalid call FD handling

[Eelco Chaudron <echaudro@redhat.com>]

This patch fixes cases where IRQ injection is tried while
the call FD is not valid, which should not happen.

Fixes: b1cce26af1dc ("vhost: add notification for packed ring")
Fixes: e37ff954405a ("vhost: support virtqueue interrupt/notification suppression")

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
---
 lib/vhost/vhost.h |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
index 37609c7c8d..23a4e2b1a7 100644
--- a/lib/vhost/vhost.h
+++ b/lib/vhost/vhost.h
@@ -903,9 +903,9 @@ vhost_vring_call_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
 			"%s: used_event_idx=%d, old=%d, new=%d\n",
 			__func__, vhost_used_event(vq), old, new);
 
-		if ((vhost_need_event(vhost_used_event(vq), new, old) &&
-					(vq->callfd >= 0)) ||
-				unlikely(!signalled_used_valid)) {
+		if ((vhost_need_event(vhost_used_event(vq), new, old) ||
+					unlikely(!signalled_used_valid)) &&
+				vq->callfd >= 0) {
 			eventfd_write(vq->callfd, (eventfd_t) 1);
 			if (dev->flags & VIRTIO_DEV_STATS_ENABLED)
 				__atomic_fetch_add(&vq->stats.guest_notifications,
@@ -974,7 +974,7 @@ vhost_vring_call_packed(struct virtio_net *dev, struct vhost_virtqueue *vq)
 	if (vhost_need_event(off, new, old))
 		kick = true;
 kick:
-	if (kick) {
+	if (kick && vq->callfd >= 0) {
 		eventfd_write(vq->callfd, (eventfd_t)1);
 		if (dev->notify_ops->guest_notified)
 			dev->notify_ops->guest_notified(dev->vid);