[PATCH v2 03/16] vfio/ccw: allow non-zero storage keys

Eric Farman
2022-12-20T17:12:28Z

Currently, vfio-ccw copies the ORB from the io_region to the
channel_program struct being built. It then adjusts various
pieces of that ORB to the values needed to be used by the
SSCH issued by vfio-ccw in the host.

This includes setting the subchannel key to the default,
presumably because Linux doesn't do anything with non-zero
storage keys itself. But it seems wrong to convert every I/O
to the default key if the guest itself requested a non-zero
subchannel (access) key.

Any channel program that sets a non-zero key would expect the
same key returned in the SCSW of the IRB, not zero, so best to
allow that to occur unimpeded.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
drivers/s390/cio/vfio_ccw_cp.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index a0060ef1119e..268a90252521 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -836,7 +836,6 @@ union orb *cp_get_orb(struct channel_program *cp, struct subchannel *sch)

orb->cmd.intparm = (u32)virt_to_phys(sch);
orb->cmd.fmt = 1;
- orb->cmd.key = PAGE_DEFAULT_KEY >> 4;

if (orb->cmd.lpm == 0)
orb->cmd.lpm = sch->lpm;
--
2.34.1