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authorCornelia Huck <cohuck@redhat.com>2019-03-11 10:59:53 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-03 06:25:21 +0200
commit2cca5be88ac06622da6c6aaa8a2dc7d0ed28c25e (patch)
tree14aa5fcbc1f7b2c7290e77a179fd9fb079b1ebf7
parent1cb3e7f166b5c3efea42d2576eb2d4625a6c81ac (diff)
vfio: ccw: only free cp on final interrupt
commit 50b7f1b7236bab08ebbbecf90521e84b068d7a17 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/s390/cio/vfio_ccw_drv.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index ae7a49ade414..d22759eb6640 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -70,20 +70,24 @@ 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;
}