vfio-ccw only supports command mode for channel programs, not transport mode. User space is supposed to already take care of that and pass us command-mode ORBs only, but better make sure and return an error to the caller instead of trying to process tcws as ccws. Signed-off-by: Cornelia Huck <cohuck@xxxxxxxxxx> --- drivers/s390/cio/vfio_ccw_fsm.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c index c30420c517b1..ff6963ad6e39 100644 --- a/drivers/s390/cio/vfio_ccw_fsm.c +++ b/drivers/s390/cio/vfio_ccw_fsm.c @@ -124,6 +124,11 @@ static void fsm_io_request(struct vfio_ccw_private *private, if (scsw->cmd.fctl & SCSW_FCTL_START_FUNC) { orb = (union orb *)io_region->orb_area; + /* Don't try to build a cp if transport mode is specified. */ + if (orb->tm.b) { + io_region->ret_code = -EOPNOTSUPP; + goto err_out; + } io_region->ret_code = cp_init(&private->cp, mdev_dev(mdev), orb); if (io_region->ret_code) -- 2.13.6