Re: [PATCH v2 4/5] KVM: s390: vsie: Fix redundant rmap entries

[Christian Borntraeger <borntraeger@de.ibm.com>]

Am 12.05.26 um 19:52 schrieb Claudio Imbrenda:
> The address passed to the gmap rmap was not being masked. As a
> consequence several different (but functionally equivalent) rmap
> entries were being created for each shadowed table.
> 
> Fix this by properly masking the address depending on the table level.
> 
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>

> ---
>   arch/s390/kvm/gmap.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/s390/kvm/gmap.c b/arch/s390/kvm/gmap.c
> index 8cff0cf5ce24..957126ab991c 100644
> --- a/arch/s390/kvm/gmap.c
> +++ b/arch/s390/kvm/gmap.c
> @@ -1025,6 +1025,7 @@ int gmap_insert_rmap(struct gmap *sg, gfn_t p_gfn, gfn_t r_gfn, int level)
>   int gmap_protect_rmap(struct kvm_s390_mmu_cache *mc, struct gmap *sg, gfn_t p_gfn, gfn_t r_gfn,
>   		      kvm_pfn_t pfn, int level, bool wr)
>   {
> +	unsigned long bitmask;
>   	union crste *crstep;
>   	union pgste pgste;
>   	union pte *ptep;
> @@ -1041,8 +1042,9 @@ int gmap_protect_rmap(struct kvm_s390_mmu_cache *mc, struct gmap *sg, gfn_t p_gf
>   	if (rc)
>   		return rc;
>   	if (level <= TABLE_TYPE_REGION1) {
> +		bitmask = -1UL << (8 + 11 * level);
>   		scoped_guard(spinlock, &sg->host_to_rmap_lock)
> -			rc = gmap_insert_rmap(sg, p_gfn, r_gfn, level);
> +			rc = gmap_insert_rmap(sg, p_gfn, r_gfn & bitmask, level);
>   	}
>   	if (rc)
>   		return rc;