Handle the virtio-ccw revision according to what the guest sets.
When revision 1 is selected, we have a virtio-1 standard device
with byteswapping for the virtio rings.
When a channel gets disabled, we have to revert to the legacy behavior
in case the next user of the device does not negotiate the revision 1
anymore (e.g. the boot firmware uses revision 1, but the operating
system only uses the legacy mode).
Note that revisions > 0 are still disabled.
[CH: assure memory accesses are always BE]
Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
c42767f2bb