Re: [PATCH] s390x/s390-virtio-ccw: Reset PCI devices during subsystem reset

[Matthew Rosato]

On 10/15/20 9:37 AM, Niklas Schnelle wrote:
> On 10/15/20 3:34 PM, Christian Borntraeger wrote:
> > On 15.10.20 15:32, Christian Borntraeger wrote:
> > > On 15.10.20 15:16, Matthew Rosato wrote:
> > > > Currently, a subsystem reset event leaves PCI devices enabled, causing
> > > > issues post-reset in the guest (an example would be after a kexec).  These
> > > > devices need to be reset during a subsystem reset, allowing them to be
> > > > properly re-enabled afterwards.  Add the S390 PCI host bridge to the list
> > > > of qdevs to be reset during subsystem reset.
> > > >
> > > > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> > > > Reviewed-by: Eric Farman <farman@linux.ibm.com>
> > >
> > > Makese sense.
> > > Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
> >
> > A question. Is this a stable candidate?
>
> As this can prevent a SUSE guest (which does kexec during boot because of grub)
> from seeing any PCI devices I'd say yes.

Yes, agreed.

> > > > ---
> > > >   hw/s390x/s390-virtio-ccw.c | 1 +
> > > >   1 file changed, 1 insertion(+)
> > > >
> > > > diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> > > > index e52182f..2e90033 100644
> > > > --- a/hw/s390x/s390-virtio-ccw.c
> > > > +++ b/hw/s390x/s390-virtio-ccw.c
> > > > @@ -101,6 +101,7 @@ static const char *const reset_dev_types[] = {
> > > >       "s390-sclp-event-facility",
> > > >       "s390-flic",
> > > >       "diag288",
> > > > +    TYPE_S390_PCI_HOST_BRIDGE,
> > > >   };
> > > >   
> > > >   static void subsystem_reset(void)