[PATCH 1/7] vhost: fix missing vring call check on virtqueue access

[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: c5736998305d ("vhost: fix missing virtqueue lock protection")
Fixes: 830f7e790732 ("vhost: add non-blocking API for posting interrupt")
Cc: stable at dpdk.org

Reported-by: Li Feng <fengli at smartx.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
 lib/vhost/vhost.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index c03bb9c6eb..e9c775fa26 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -1328,6 +1328,7 @@ rte_vhost_vring_call(int vid, uint16_t vring_idx)
 {
 	struct virtio_net *dev;
 	struct vhost_virtqueue *vq;
+	int ret = 0;
 
 	dev = get_device(vid);
 	if (!dev)
@@ -1342,14 +1343,20 @@ rte_vhost_vring_call(int vid, uint16_t vring_idx)
 
 	rte_rwlock_read_lock(&vq->access_lock);
 
+	if (unlikely(!vq->access_ok)) {
+		ret = -1;
+		goto out_unlock;
+	}
+
 	if (vq_is_packed(dev))
 		vhost_vring_call_packed(dev, vq);
 	else
 		vhost_vring_call_split(dev, vq);
 
+out_unlock:
 	rte_rwlock_read_unlock(&vq->access_lock);
 
-	return 0;
+	return ret;
 }
 
 int
@@ -1357,6 +1364,7 @@ rte_vhost_vring_call_nonblock(int vid, uint16_t vring_idx)
 {
 	struct virtio_net *dev;
 	struct vhost_virtqueue *vq;
+	int ret = 0;
 
 	dev = get_device(vid);
 	if (!dev)
@@ -1372,14 +1380,20 @@ rte_vhost_vring_call_nonblock(int vid, uint16_t vring_idx)
 	if (rte_rwlock_read_trylock(&vq->access_lock))
 		return -EAGAIN;
 
+	if (unlikely(!vq->access_ok)) {
+		ret = -1;
+		goto out_unlock;
+	}
+
 	if (vq_is_packed(dev))
 		vhost_vring_call_packed(dev, vq);
 	else
 		vhost_vring_call_split(dev, vq);
 
+out_unlock:
 	rte_rwlock_read_unlock(&vq->access_lock);
 
-	return 0;
+	return ret;
 }
 
 uint16_t
-- 
2.41.0