This writes a register and reads its 1/2/4 byte parts.  Masking
is done in the device model.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NAnthony Liguori <aliguori@us.ibm.com>
Message-id: 1374501278-31549-25-git-send-email-pbonzini@redhat.com
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>