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

[Chenyi Qiang]

On 7/30/2021 1:45 AM, Paolo Bonzini wrote:
> 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.

Will split out the pke and pks.

Thanks
Chenyi

> Paolo