* [PULL 1/1] vfio: ccw: only free cp on final interrupt
[not found] <20190311162656.10067-1-cohuck@redhat.com>
@ 2019-03-11 16:26 ` Cornelia Huck
2019-03-11 17:24 ` [PULL 0/1] vfio-ccw: fix for 5.1 Martin Schwidefsky
1 sibling, 0 replies; 2+ messages in thread
From: Cornelia Huck @ 2019-03-11 16:26 UTC (permalink / raw)
To: Martin Schwidefsky, Heiko Carstens
Cc: Farhan Ali, Eric Farman, Halil Pasic, linux-s390, kvm,
Cornelia Huck, stable
When we get an interrupt for a channel program, it is not
necessarily the final interrupt; for example, the issuing
guest may request an intermediate interrupt by specifying
the program-controlled-interrupt flag on a ccw.
We must not switch the state to idle if the interrupt is not
yet final; even more importantly, we must not free the translated
channel program if the interrupt is not yet final, or the host
can crash during cp rewind.
Fixes: e5f84dbaea59 ("vfio: ccw: return I/O results asynchronously")
Cc: stable@vger.kernel.org # v4.12+
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---
drivers/s390/cio/vfio_ccw_drv.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index a10cec0e86eb..0b3b9de45c60 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -72,20 +72,24 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work)
{
struct vfio_ccw_private *private;
struct irb *irb;
+ bool is_final;
private = container_of(work, struct vfio_ccw_private, io_work);
irb = &private->irb;
+ is_final = !(scsw_actl(&irb->scsw) &
+ (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
if (scsw_is_solicited(&irb->scsw)) {
cp_update_scsw(&private->cp, &irb->scsw);
- cp_free(&private->cp);
+ if (is_final)
+ cp_free(&private->cp);
}
memcpy(private->io_region->irb_area, irb, sizeof(*irb));
if (private->io_trigger)
eventfd_signal(private->io_trigger, 1);
- if (private->mdev)
+ if (private->mdev && is_final)
private->state = VFIO_CCW_STATE_IDLE;
}
--
2.17.2
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