Re: [PATCH] s390/vfio-ap: Clean up vfio_ap resources when KVM pointer invalidated

[Tony Krowiak]

On 12/3/20 12:01 PM, Halil Pasic wrote:
> On Thu, 3 Dec 2020 11:19:07 +0100
> Cornelia Huck <cohuck@xxxxxxxxxx> wrote:
>
> > > @@ -1095,7 +1106,7 @@ static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,
> > >   	matrix_mdev = container_of(nb, struct ap_matrix_mdev, group_notifier);
> > >   
> > >   	if (!data) {
> > > -		matrix_mdev->kvm = NULL;
> > > +		vfio_ap_mdev_put_kvm(matrix_mdev);
> > Hm. I'm wondering whether you need to hold the maxtrix_dev lock here as
> > well?
> In v12 we eventually did come along and patch "s390/vfio-ap: allow hot
> plug/unplug of AP resources using mdev device" made this a part of a
> critical section protected by the matrix_dev->lock.
>
> IMHO the cleanup should definitely happen with the matrix_dev->lock held.

Agreed!

> Regards,
> Halil