From: Michael Kawano <mkawano@linux.ibm.com>

Date: Thu, 7 Jul 2022 15:57:27 +0200

Subject: vfio/ccw: Remove UUID from s390 debug log

Git-commit: 3566ee1d776c1393393564b2514f9cd52a49c16e

Patch-mainline: v6.0-rc1

References: git-fixes

As vfio-ccw devices are created/destroyed, the uuid of the associated

mdevs that are recorded in $S390DBF/vfio_ccw_msg/sprintf get lost.

This is because a pointer to the UUID is stored instead of the UUID

itself, and that memory may have been repurposed if/when the logs are

examined. The result is usually garbage UUID data in the logs, though

there is an outside chance of an oops happening here.

Simply remove the UUID from the traces, as the subchannel number will

provide useful configuration information for problem determination,

and is stored directly into the log instead of a pointer.

As we were the only consumer of mdev_uuid(), remove that too.

Cc: Kirti Wankhede <kwankhede@nvidia.com>

Signed-off-by: Michael Kawano <mkawano@linux.ibm.com>

Fixes: 60e05d1cf0875 ("vfio-ccw: add some logging")

Fixes: b7701dfbf9832 ("vfio-ccw: Register a chp_event callback for vfio-ccw")

[farman: reworded commit message, added Fixes: tags]

Signed-off-by: Eric Farman <farman@linux.ibm.com>

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>

Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>

Link: https://lore.kernel.org/r/20220707135737.720765-2-farman@linux.ibm.com

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

[ ptesarik: I have kept the "mdev" local variable in fsm_io_request().

  It is still used in a call to cp_init(), because SLE15-SP4 does not

  contain upstream commit 0a58795647cd4300470788ffdbff6b29b5f00632. ]

Acked-by: Petr Tesarik <ptesarik@suse.com>

---

 drivers/s390/cio/vfio_ccw_drv.c |    5 ++---

 drivers/s390/cio/vfio_ccw_fsm.c |   24 ++++++++++++------------

 drivers/s390/cio/vfio_ccw_ops.c |    8 ++++----

 include/linux/mdev.h            |    5 -----

 4 files changed, 18 insertions(+), 24 deletions(-)

--- a/drivers/s390/cio/vfio_ccw_drv.c

+++ b/drivers/s390/cio/vfio_ccw_drv.c

@@ -14,7 +14,6 @@

 #include <linux/init.h>

 #include <linux/device.h>

 #include <linux/slab.h>

-#include <linux/uuid.h>

 #include <linux/mdev.h>

 #include <asm/isc.h>

@@ -344,8 +343,8 @@ static int vfio_ccw_chp_event(struct sub

 		return 0;

 	trace_vfio_ccw_chp_event(private->sch->schid, mask, event);

-	VFIO_CCW_MSG_EVENT(2, "%pUl (%x.%x.%04x): mask=0x%x event=%d\n",

-			   mdev_uuid(private->mdev), sch->schid.cssid,

+	VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: mask=0x%x event=%d\n",

+			   sch->schid.cssid,

 			   sch->schid.ssid, sch->schid.sch_no,

 			   mask, event);

--- a/drivers/s390/cio/vfio_ccw_fsm.c

+++ b/drivers/s390/cio/vfio_ccw_fsm.c

@@ -256,8 +256,8 @@ static void fsm_io_request(struct vfio_c

 		if (orb->tm.b) {

 			io_region->ret_code = -EOPNOTSUPP;

 			VFIO_CCW_MSG_EVENT(2,

-					   "%pUl (%x.%x.%04x): transport mode\n",

-					   mdev_uuid(mdev), schid.cssid,

+					   "sch %x.%x.%04x: transport mode\n",

+					   schid.cssid,

 					   schid.ssid, schid.sch_no);

 			errstr = "transport mode";

 			goto err_out;

@@ -266,8 +266,8 @@ static void fsm_io_request(struct vfio_c

 					      orb);

 		if (io_region->ret_code) {

 			VFIO_CCW_MSG_EVENT(2,

-					   "%pUl (%x.%x.%04x): cp_init=%d\n",

-					   mdev_uuid(mdev), schid.cssid,

+					   "sch %x.%x.%04x: cp_init=%d\n",

+					   schid.cssid,

 					   schid.ssid, schid.sch_no,

 					   io_region->ret_code);

 			errstr = "cp init";

@@ -277,8 +277,8 @@ static void fsm_io_request(struct vfio_c

 		io_region->ret_code = cp_prefetch(&private->cp);

 		if (io_region->ret_code) {

 			VFIO_CCW_MSG_EVENT(2,

-					   "%pUl (%x.%x.%04x): cp_prefetch=%d\n",

-					   mdev_uuid(mdev), schid.cssid,

+					   "sch %x.%x.%04x: cp_prefetch=%d\n",

+					   schid.cssid,

 					   schid.ssid, schid.sch_no,

 					   io_region->ret_code);

 			errstr = "cp prefetch";

@@ -290,8 +290,8 @@ static void fsm_io_request(struct vfio_c

 		io_region->ret_code = fsm_io_helper(private);

 		if (io_region->ret_code) {

 			VFIO_CCW_MSG_EVENT(2,

-					   "%pUl (%x.%x.%04x): fsm_io_helper=%d\n",

-					   mdev_uuid(mdev), schid.cssid,

+					   "sch %x.%x.%04x: fsm_io_helper=%d\n",

+					   schid.cssid,

 					   schid.ssid, schid.sch_no,

 					   io_region->ret_code);

 			errstr = "cp fsm_io_helper";

@@ -301,16 +301,16 @@ static void fsm_io_request(struct vfio_c

 		return;

 	} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {

 		VFIO_CCW_MSG_EVENT(2,

-				   "%pUl (%x.%x.%04x): halt on io_region\n",

-				   mdev_uuid(mdev), schid.cssid,

+				   "sch %x.%x.%04x: halt on io_region\n",

+				   schid.cssid,

 				   schid.ssid, schid.sch_no);

 		/* halt is handled via the async cmd region */

 		io_region->ret_code = -EOPNOTSUPP;

 		goto err_out;

 	} else if (scsw->cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {

 		VFIO_CCW_MSG_EVENT(2,

-				   "%pUl (%x.%x.%04x): clear on io_region\n",

-				   mdev_uuid(mdev), schid.cssid,

+				   "sch %x.%x.%04x: clear on io_region\n",

+				   schid.cssid,

 				   schid.ssid, schid.sch_no);

 		/* clear is handled via the async cmd region */

 		io_region->ret_code = -EOPNOTSUPP;

--- a/drivers/s390/cio/vfio_ccw_ops.c

+++ b/drivers/s390/cio/vfio_ccw_ops.c

@@ -127,8 +127,8 @@ static int vfio_ccw_mdev_create(struct m

 	private->mdev = mdev;

 	private->state = VFIO_CCW_STATE_IDLE;

-	VFIO_CCW_MSG_EVENT(2, "mdev %pUl, sch %x.%x.%04x: create\n",

-			   mdev_uuid(mdev), private->sch->schid.cssid,

+	VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: create\n",

+			   private->sch->schid.cssid,

 			   private->sch->schid.ssid,

 			   private->sch->schid.sch_no);

@@ -140,8 +140,8 @@ static int vfio_ccw_mdev_remove(struct m

 	struct vfio_ccw_private *private =

 		dev_get_drvdata(mdev_parent_dev(mdev));

-	VFIO_CCW_MSG_EVENT(2, "mdev %pUl, sch %x.%x.%04x: remove\n",

-			   mdev_uuid(mdev), private->sch->schid.cssid,

+	VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: remove\n",

+			   private->sch->schid.cssid,

 			   private->sch->schid.ssid,

 			   private->sch->schid.sch_no);

--- a/include/linux/mdev.h

+++ b/include/linux/mdev.h

@@ -166,11 +166,6 @@ static inline void mdev_set_drvdata(stru

 {

 	mdev->driver_data = data;

 }

-static inline const guid_t *mdev_uuid(struct mdev_device *mdev)

-{

-	return &mdev->uuid;

-}

-

 extern struct bus_type mdev_bus_type;

 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops);