summaryrefslogtreecommitdiff
path: root/drivers/vhost/vhost.c
diff options
context:
space:
mode:
authorJason Wang <jasowang@redhat.com>2018-12-13 10:53:37 +0800
committerDavid S. Miller <davem@davemloft.net>2018-12-12 21:56:19 -0800
commit841df922417eb82c835e93d4b93eb6a68c99d599 (patch)
tree0286f8784c5eafeda7b38db9cc989780b34387cf /drivers/vhost/vhost.c
parent3b076cfe86be3784dee93cfd83d6913a9ef530ee (diff)
vhost: make sure used idx is seen before log in vhost_add_used_n()
We miss a write barrier that guarantees used idx is updated and seen before log. This will let userspace sync and copy used ring before used idx is update. Fix this by adding a barrier before log_write(). Fixes: 8dd014adfea6f ("vhost-net: mergeable buffers support") Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/vhost/vhost.c')
-rw-r--r--drivers/vhost/vhost.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 6b98d8e3a5bf..5915f240275a 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2220,6 +2220,8 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
return -EFAULT;
}
if (unlikely(vq->log_used)) {
+ /* Make sure used idx is seen before log. */
+ smp_wmb();
/* Log used index update. */
log_write(vq->log_base,
vq->log_addr + offsetof(struct vring_used, idx),