[PATCH 4/7] vhost: fix check on virtqueue access in async registration

[Maxime Coquelin]

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: 78639d54563a ("vhost: introduce async enqueue registration API")
Cc: stable at dpdk.org

Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
 lib/vhost/vhost.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index f07674334d..7f5d25255a 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -1853,7 +1853,15 @@ rte_vhost_async_channel_register(int vid, uint16_t queue_id)
 		return -1;
 
 	rte_rwlock_write_lock(&vq->access_lock);
+
+	if (unlikely(!vq->access_ok)) {
+		ret = -1;
+		goto out_unlock;
+	}
+
 	ret = async_channel_register(dev, vq);
+
+out_unlock:
 	rte_rwlock_write_unlock(&vq->access_lock);
 
 	return ret;
@@ -1905,6 +1913,11 @@ rte_vhost_async_channel_unregister(int vid, uint16_t queue_id)
 		return ret;
 	}
 
+	if (unlikely(!vq->access_ok)) {
+		ret = -1;
+		goto out_unlock;
+	}
+
 	if (!vq->async) {
 		ret = 0;
 	} else if (vq->async->pkts_inflight_n) {
@@ -1916,6 +1929,7 @@ rte_vhost_async_channel_unregister(int vid, uint16_t queue_id)
 		ret = 0;
 	}
 
+out_unlock:
 	rte_rwlock_write_unlock(&vq->access_lock);
 
 	return ret;
-- 
2.41.0