[PATCH 3/7] vhost: fix checking virtqueue access when notifying guest

[Maxime Coquelin <maxime.coquelin@redhat.com>]

Acquiring the access lock is not enough to ensure
virtqueue's metadata such as vring pointers are valid.

The access status must also be checked.

Fixes: d761d455a0e4 ("vhost: add operation to offload the interrupt kick")
Cc: stable@dpdk.org

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

diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index 83b71ffb23..f07674334d 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -1540,6 +1540,9 @@ rte_vhost_notify_guest(int vid, uint16_t queue_id)
 
 	rte_rwlock_read_lock(&vq->access_lock);
 
+	if (unlikely(!vq->access_ok))
+		goto out_unlock;
+
 	if (dev->backend_ops->inject_irq(dev, vq)) {
 		if (dev->flags & VIRTIO_DEV_STATS_ENABLED)
 			__atomic_fetch_add(&vq->stats.guest_notifications_error,
@@ -1552,6 +1555,7 @@ rte_vhost_notify_guest(int vid, uint16_t queue_id)
 			dev->notify_ops->guest_notified(dev->vid);
 	}
 
+out_unlock:
 	rte_rwlock_read_unlock(&vq->access_lock);
 }
 
-- 
2.41.0