Re: [RFC PATCH v5 033/104] KVM: x86: Add infrastructure for stolen GPA bits

[Paolo Bonzini]

On 4/6/22 04:23, Kai Huang wrote:
> > > >   
> > > > -		gfn = gpte_to_gfn(gpte);
> > > > +		gfn = gpte_to_gfn(vcpu, gpte);
> > > >   		pte_access = sp->role.access;
> > > >   		pte_access &= FNAME(gpte_access)(gpte);
> > > >   		FNAME(protect_clean_gpte)(vcpu->arch.mmu, &pte_access, gpte);
> > >
> > > In commit message you mentioned "Don't support stolen bits for shadow EPT" (you
> > > actually mean shadow MMU I suppose), yet there's bunch of code change to shadow
> > > MMU.
> >
> > It's a bit ugly, but it's uglier to keep two versions of gpte_to_gfn.
>
> gpte_to_gfn() is only used in paging_tmpl.h.  Could you elaborate why we need to
> keep two versions of it?

You're right.  Yeah, considering page table walks are not supported when 
private memory is available, it shouldn't be necessary to change 
paging_tmpl.h.

Paolo