[PATCH v3 2/3] vhost: Use vhost_get_used_size() in vhost_vring_set_addr()

From: Greg Kurz
Date: Sat Oct 03 2020 - 06:02:20 EST


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().

Signed-off-by: Greg Kurz <groug@xxxxxxxx>
---
drivers/vhost/vhost.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c3b49975dc28..9d2c225fb518 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1519,8 +1519,7 @@ static long vhost_vring_set_addr(struct vhost_dev *d,
/* 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;
}