Re: [PATCH 2/4] KVM: x86/mmu: Bug the VM if KVM attempts to walk more levels than the MMU has

[Sean Christopherson]

On Thu, Aug 27, 2026, Yosry Ahmed wrote:
> On Wed, Aug 26, 2026 at 2:18 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
> >
> > Extend the "EFER.LMA && !CR4.PAE" check, which exists largely to guard
> > against KVM configuring a paging32 MMU with more than 2 levels of paging,
> 
> Is there value in keeping the original check? I suppose yes as you
> said it exists "largely" for this, but it would probably be nice to
> spell it out (if we know).

Because LMA && !PAE is still an illegal combination.  The symptom we know about
is a misconfiguration of base.level vs. the paging template, but I also want to
guard against any other symptoms that stem from the bad state.