Re: [PATCH v2] s390: vsie: Use effective CRYCBD.31 to check CRYCBD validity

[Cornelia Huck]

On Mon, 11 Feb 2019 10:20:49 +0100
Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:

> When facility.76 MSAX3 is present for the guest we must issue a validity
> interception if the CRYCBD is not valid.
> 
> The bit CRYCBD.31 is an effective field and tested at each guest
> level and has for effect to mask the facility.76
> 
> It follows that if CRYCBD.31 is clear and AP is not in use  we do not
> have to test the CRYCBD validatity even facility.76 is present in the

s/even/even if/

> host.
> 
> Fixes: 6ee74098201b ("KVM: s390: vsie: allow CRYCB FORMAT-0")
> Cc: stable@xxxxxxxxxxxxxxx
> 
> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> Reported-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
> Acked-by: David Hildenbrand <david@xxxxxxxxxx>
> ---
>  arch/s390/kvm/vsie.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
> index a153257..d62fa14 100644
> --- a/arch/s390/kvm/vsie.c
> +++ b/arch/s390/kvm/vsie.c
> @@ -297,7 +297,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
>  	scb_s->crycbd = 0;
>  
>  	apie_h = vcpu->arch.sie_block->eca & ECA_APIE;
> -	if (!apie_h && !key_msk)
> +	if (!apie_h && (!key_msk || fmt_o == CRYCB_FORMAT0))
>  		return 0;
>  
>  	if (!crycb_addr)

Acked-by: Cornelia Huck <cohuck@xxxxxxxxxx>