| Message ID | 20190311102025.23941-1-cohuck@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vfio: ccw: only free cp on final interrupt | expand |
On 03/11/2019 06:20 AM, Cornelia Huck wrote: > 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+ > Signed-off-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> > --- > > Previously part of "vfio-ccw: rework ssch state handling". Please review, > I plan to send a pull req asap. > > --- > 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; > } > >
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; }
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+ Signed-off-by: Cornelia Huck <cohuck@redhat.com> --- Previously part of "vfio-ccw: rework ssch state handling". Please review, I plan to send a pull req asap. --- drivers/s390/cio/vfio_ccw_drv.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)