From: Greg Kurz <[email protected]>

commit 71878fa46c7e3b40fa7b3f1b6e4ba3f92f1ac359 upstream.

The open-coded computation of the used size doesn't take the event
into account when the VIRTIO_RING_F_EVENT_IDX feature is present.
Fix that by using vhost_get_used_size().

Fixes: 8ea8cf89e19a ("vhost: support event index")
Cc: [email protected]
Signed-off-by: Greg Kurz <[email protected]>
Link: 
https://lore.kernel.org/r/[email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/vhost/vhost.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1545,8 +1545,7 @@ static long vhost_vring_set_addr(struct
                /* Also validate log access for used ring if enabled. */
                if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
                        !log_access_ok(vq->log_base, a.log_guest_addr,
-                               sizeof *vq->used +
-                               vq->num * sizeof *vq->used->ring))
+                                      vhost_get_used_size(vq, vq->num)))
                        return -EINVAL;
        }
 


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