Re: [PATCH v3 1/1] KVM: s390: pv: fix race when making a page secure

[David Hildenbrand]

On 04.03.25 10:21, Claudio Imbrenda wrote:
> On Fri, 28 Feb 2025 22:15:04 +0100
> David Hildenbrand <david@xxxxxxxxxx> wrote:
>
> > On 27.02.25 14:09, Claudio Imbrenda wrote:
> > > Holding the pte lock for the page that is being converted to secure is
> > > needed to avoid races. A previous commit removed the locking, which
> > > caused issues. Fix by locking the pte again.
> > >
> > > Fixes: 5cbe24350b7d ("KVM: s390: move pv gmap functions into kvm")
> > > Reported-by: David Hildenbrand <david@xxxxxxxxxx>
> > > Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
> >
> > Tested with shmem / memory-backend-memfd that ends up using large folios
> > / THPs.
> >
> > Tested-by: David Hildenbrand <david@xxxxxxxxxx>
> > Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
> >
> > Two comments below.
>
> I will need to send a v4, unfortunately there are other issues with this
> patch (as you have probably noticed by now as well)

I ran into some weird KVM_PV_VERIFY issues a couple of times, but did 
not find the root cause so far.

Is that what you are seeing? (and what is the root cause? :) )

--
Cheers,

David / dhildenb