Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 86e9424d authored by Michael S. Tsirkin's avatar Michael S. Tsirkin
Browse files

vhost: logging thinko fix 



vhost was dong some complex math to get
offset to log at, and got it wrong by a couple of bytes,
while in fact it's simple: get address where we write,
subtract start of buffer, add log base.

Do it this way.

Reviewed-by: default avatarJuan Quintela <quintela@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 655ffee2

drivers/vhost/vhost.c

+8 −4
Original line number Diff line number Diff line
@@ -1004,10 +1004,14 @@ int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) 
	if (unlikely(vq->log_used)) {

		/* Make sure data is seen before log. */

		smp_wmb();

		log_write(vq->log_base, vq->log_addr + sizeof *vq->used->ring *

			  (vq->last_used_idx % vq->num),

			  sizeof *vq->used->ring);

		log_write(vq->log_base, vq->log_addr, sizeof *vq->used->ring);

		/* Log used ring entry write. */

		log_write(vq->log_base,

			  vq->log_addr + ((void *)used - (void *)vq->used),

			  sizeof *used);

		/* Log used index update. */

		log_write(vq->log_base,

			  vq->log_addr + offsetof(struct vring_used, idx),

			  sizeof vq->used->idx);

		if (vq->log_ctx)

			eventfd_signal(vq->log_ctx, 1);

	}