We can use this in virtio-net code as well as new Rocker driver code, so
up-level this.
Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1426306173-24884-2-git-send-email-sfeldma@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>