Re: [PATCH 05/54] Revert "KVM: x86/mmu: Drop kvm_mmu_extended_role.cr4_la57 hack"

[Paolo Bonzini]

On 25/06/21 11:29, Yu Zhang wrote:
> Thanks, Paolo.
>
> Do you mean the L1 can modify its paging mode by setting HOST_CR3 as root of
> a PML5 table in VMCS12 and HOST_CR4 with LA57 flipped in VMCS12, causing the
> GUEST_CR3/4 being changed in VMCS01, and eventually updating the CR3/4 when
> L0 is injecting a VM Exit from L2?

Yes, you can even do that without a "full" vmentry by setting invalid 
guest state in vmcs12. :)

Paolo