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Commit 2cca5be8 authored by Cornelia Huck's avatar Cornelia Huck Committed by Greg Kroah-Hartman
Browse files

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: e5f84dba ("vfio: ccw: return I/O results asynchronously")
Cc: stable@vger.kernel.org # v4.12+
Reviewed-by: default avatarEric Farman <farman@linux.ibm.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1cb3e7f1

drivers/s390/cio/vfio_ccw_drv.c

+6 −2
Original line number Diff line number Diff line
@@ -70,12 +70,16 @@ 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);

		if (is_final)

			cp_free(&private->cp);

	}

	memcpy(private->io_region.irb_area, irb, sizeof(*irb));
@@ -83,7 +87,7 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work) 
	if (private->io_trigger)

		eventfd_signal(private->io_trigger, 1);



	if (private->mdev)

	if (private->mdev && is_final)

		private->state = VFIO_CCW_STATE_IDLE;

}