Re: [PATCH v9 07/22] KVM: s390: refactor crypto initialization

[Tony Krowiak]

On 08/20/2018 04:41 PM, David Hildenbrand wrote:
> > > > +	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_AP))
> > > > +		vcpu->arch.sie_block->eca |= ECA_APIE;
> > > >    
> > > > -	vcpu->arch.sie_block->crycbd = vcpu->kvm->arch.crypto.crycbd;
> > > > +	/* If MSAX3 is installed on the guest, set up protected key support */
> > > > +	if (test_kvm_facility(vcpu->kvm, 76)) {
> > > > +		if (vcpu->kvm->arch.crypto.aes_kw)
> > > > +			vcpu->arch.sie_block->ecb3 |= ECB3_AES;
> > > > +		if (vcpu->kvm->arch.crypto.dea_kw)
> > > > +			vcpu->arch.sie_block->ecb3 |= ECB3_DEA;
> > > > +	}
> > > As the feature can never change, and aes_kw/dea_kw are only set to 1 in
> > > case we have test_kvm_facility(vcpu->kvm, 76), this change is not needed.
> > >
> > > I think this function can be pretty much left alone. Just add the
> > > KVM_S390_VM_CPU_FEAT_AP handling.
> > I disagree, what about the case where the KVM_S390_VM_CPU_FEAT_AP is
> > configured for the guest but the MSAX3 facility (76) is not?
> Then aes_kw/dea_kw can never be set.
>
> kvm_s390_vm_set_crypto() and kvm_s390_crypto_init() correctly test for
> facility 76.
>
> Or am I missing a case?

I stand corrected, you are right. I'll remove the test.

> > > >    }
> > > >    
> > > >    void kvm_s390_vcpu_unsetup_cmma(struct kvm_vcpu *vcpu)