[dpdk-dev] [PATCH 2/5] vhost: enforce desc flags and content read ordering

[Maxime Coquelin]

A read barrier is required to ensure that the ordering between
descriptor's flags and content reads is enforced.

Fixes: 2f3225a7d69b ("vhost: add vector filling support for packed ring")
Cc: stable at dpdk.org

Reported-by: Jason Wang <jasowang at redhat.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
 lib/librte_vhost/virtio_net.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index f11ebb54f..68b72e7a5 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -520,6 +520,12 @@ fill_vec_buf_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	if (unlikely(!desc_is_avail(&descs[avail_idx], wrap_counter)))
 		return -1;
 
+	/*
+	 * The ordering between desc flags and desc
+	 * content reads need to be enforced.
+	 */
+	rte_smp_rmb();
+
 	*desc_count = 0;
 	*len = 0;
 
-- 
2.17.2