Re: [PATCH v4 4/5] KVM: MMU: Add support for PKS emulation

[Paolo Bonzini]

On 29/07/21 19:25, Sean Christopherson wrote:
> > -		unsigned int cr4_pke:1;
> > +		unsigned int cr4_pkr:1;
> Smushing these together will not work, as this code (from below)
>
> > -     ext.cr4_pke = !!kvm_read_cr4_bits(vcpu, X86_CR4_PKE);
> > +     ext.cr4_pkr = !!kvm_read_cr4_bits(vcpu, X86_CR4_PKE) ||
> > +                   !!kvm_read_cr4_bits(vcpu, X86_CR4_PKS);
> will generate the same mmu_role for CR4.PKE=0,PKS=1 and CR4.PKE=1,PKS=1 (and
> other combinations).  I.e. KVM will fail to reconfigure the MMU and thus skip
> update_pkr_bitmask() if the guest toggles PKE or PKS while the other PK* bit is set.

I'm also not sure why there would be issues in just using cr4_pks.

Paolo