Re: [PATCH v2 5/5] KVM: s390: Properly reset zero bit in PGSTE

[Christian Borntraeger]

Am 12.05.26 um 19:52 schrieb Claudio Imbrenda:
> When calling _gmap_ptep_xchg(), always clear the pgste.zero bit. This
> prevents the page from being accidentally discarded when getting
> unmapped.

Ideally have some example in the patch description, that makes review easier.> 
> Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>

Was this broken before the rework as well? Do we need a stable backport into 6.19
and older?

> ---
>   arch/s390/kvm/gmap.h | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/arch/s390/kvm/gmap.h b/arch/s390/kvm/gmap.hcd R
> index e490f2995a26..4de9ed8d58ba 100644
> --- a/arch/s390/kvm/gmap.h
> +++ b/arch/s390/kvm/gmap.h
> @@ -199,6 +199,7 @@ static inline union pgste _gmap_ptep_xchg(struct gmap *gmap, union pte *ptep, un
>   	}
>   	if (!ptep->s.d && newpte.s.d && !newpte.s.s)
>   		SetPageDirty(pfn_to_page(newpte.h.pfra));
> +	pgste.zero = 0;
>   	return __dat_ptep_xchg(ptep, pgste, newpte, gfn, gmap->asce, uses_skeys(gmap));
>   }
>