Some devices (namely virtio-scsi, virtio-gpu, virtio-keyboard,
virtio-tablet and virtio-mouse, plus virtio-crypto which is
not supported by libvirt) don't follow the same rules as all
other virtio devices, which is something that ought to be
documented.
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>
Reviewed-by: NCole Robinson <crobinso@redhat.com>