Re: [PATCH] KVM: s390: vsie: Do not shadow CRYCB when no AP and no keys

[Pierre Morel]

On 26/04/2019 11:08, Christian Borntraeger wrote:
> On 26.04.19 10:56, Pierre Morel wrote:
> > When the guest do not have AP instructions nor Key management
> > we should return without shadowing the CRYCB.
> >
> > We did not check correctly in the past.
> >
> > Fixes: b10bd9a256ae ("s390: vsie: Use effective CRYCBD.31 to check CRYCBD
> > validity")
> > Fixes: 6ee74098201b ("KVM: s390: vsie: allow CRYCB FORMAT-0")
> >
> > Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> > Reported-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> Tested-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>

Thanks,
It gives a better feeling on this patch.

Pierre

> > ---
> >   arch/s390/kvm/vsie.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
> > index c6983d9..ac411e9 100644
> > --- a/arch/s390/kvm/vsie.c
> > +++ b/arch/s390/kvm/vsie.c
> > @@ -290,6 +290,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
> >   	u8 ecb3_flags;
> >   	u32 ecd_flags;
> >   	int apie_h;
> > +	int apie_s;
> >   	int key_msk = test_kvm_facility(vcpu->kvm, 76);
> >   	int fmt_o = crycbd_o & CRYCB_FORMAT_MASK;
> >   	int fmt_h = vcpu->arch.sie_block->crycbd & CRYCB_FORMAT_MASK;
> > @@ -298,7 +299,8 @@ 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 || fmt_o == CRYCB_FORMAT0))
> > +	apie_s = apie_h & scb_o->eca;
> > +	if (!apie_s && (!key_msk || (fmt_o == CRYCB_FORMAT0)))
> >   		return 0;
> >   
> >   	if (!crycb_addr)
> > @@ -309,7 +311,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
> >   		    ((crycb_addr + 128) & PAGE_MASK))
> >   			return set_validity_icpt(scb_s, 0x003CU);
> >   
> > -	if (apie_h && (scb_o->eca & ECA_APIE)) {
> > +	if (apie_s) {
> >   		ret = setup_apcb(vcpu, &vsie_page->crycb, crycb_addr,
> >   				 vcpu->kvm->arch.crypto.crycb,
> >   				 fmt_o, fmt_h);


--
Pierre Morel
Linux/KVM/QEMU in BÃblingen - Germany