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Diffstat (limited to 'drivers/vhost/vhost.c')
-rw-r--r--drivers/vhost/vhost.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 5c9c657ab753..750effe0f98b 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1036,7 +1036,12 @@ int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
/* This actually signals the guest, using eventfd. */
void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
- __u16 flags = 0;
+ __u16 flags;
+ /* Flush out used index updates. This is paired
+ * with the barrier that the Guest executes when enabling
+ * interrupts. */
+ smp_mb();
+
if (get_user(flags, &vq->avail->flags)) {
vq_err(vq, "Failed to get flags");
return;