[PATCH 4.16 218/272] vfio-ccw: fence off transport mode

Greg Kroah-Hartman
2018-05-28T11:14:08Z

From: Cornelia Huck <cohuck@redhat.com>

[ Upstream commit 9851bc77e62499957567e7c39a5beba7d6de6296 ]

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.

Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Acked-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/s390/cio/vfio_ccw_fsm.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -129,6 +129,11 @@ static void fsm_io_request(struct vfio_c
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)