Re: [PATCH 09/12] KVM: MMU: look for a cached PGD when going from 32-bit to 64-bit

From: Sean Christopherson
Date: Thu Feb 10 2022 - 20:38:09 EST


On Fri, Feb 11, 2022, Sean Christopherson wrote:
> On Wed, Feb 09, 2022, Paolo Bonzini wrote:
> Hmm, so it doesn't matter (yet) because shadowing 4-level NPT with 5-level NPT
> is fubar anyways[1], but this will prevent caching roots when shadowing 4-level
> NPT with 5-level NPT (have I mentioned how much I love NPT?). This can be:
>
> if (VALID_PAGE(mmu->root.hpa) && mmu->root.hpa == __pa(mmu->pae_root))

Gah, that's wrong too, it will allow the pml4_root case. *sigh* I'm fine punting
this until the special roots are less special, pml5_root is completely broken
anyways.