Re: [PATCH v16 06/14] s390/vfio-ap: refresh guest's APCB by filtering APQNs assigned to mdev

[Tony Krowiak]

On 5/24/21 12:15 PM, Halil Pasic wrote:
> On Mon, 10 May 2021 12:44:15 -0400
> Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote:
>
> > @@ -1601,8 +1676,10 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
> >   	mutex_lock(&matrix_dev->lock);
> >   	q = dev_get_drvdata(&apdev->device);
> >   
> > -	if (q->matrix_mdev)
> > +	if (q->matrix_mdev) {
> >   		vfio_ap_mdev_unlink_queue_fr_mdev(q);
> > +		vfio_ap_mdev_refresh_apcb(q->matrix_mdev);
> > +	}
> >   
> >   	vfio_ap_mdev_reset_queue(q, 1);
> >   	dev_set_drvdata(&apdev->device, NULL);
> At this point we don't know if !!kvm_busy or kvm_busy AFAICT. If
> !!kvm_busy, then we may end up changing a shadow_apcb while an other
> thread is in the middle of committing it to the SD satellite. That
> would be no good.

No, that would not be a good thing, we should check for
that.

> Regards,
> Halil