--- x/drivers/vhost/vhost.c
+++ y/drivers/vhost/vhost.c
@@ -2207,6 +2207,7 @@ int vhost_get_vq_desc(struct vhost_virtq
 	__virtio16 avail_idx;
 	__virtio16 ring_head;
 	int ret, access;
+	bool was_set = !!(vq->used_flags & VRING_USED_F_NO_NOTIFY);
 
 	/* Check it isn't doing very strange things with descriptor numbers. */
 	last_avail_idx = vq->last_avail_idx;
@@ -2332,7 +2333,7 @@ int vhost_get_vq_desc(struct vhost_virtq
 
 	/* Assume notifications from guest are disabled at this point,
 	 * if they aren't we would need to update avail_event index. */
-	BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
+	BUG_ON(!!(vq->used_flags & VRING_USED_F_NO_NOTIFY) != was_set);
 	return head;
 }
 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);