On Thu, Feb 2, 2023 at 9:21 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > This is logically correct, but there's potential (weird) functional change here. > If this is called with an invalid root, then KVM will invalidate the GVA in all > roots prior to this patch, but in no roots after this patch. > > I _think_ it should be impossible get here with an invalid root. Can you try > adding a prep patch to assert that the root is valid so that this patch can > reasonably assert that there's no functional change? > > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 508074e47bc0..fffd9b610196 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -792,6 +792,8 @@ void kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, > fault_mmu = fault->nested_page_fault ? vcpu->arch.mmu : > vcpu->arch.walk_mmu; > > + WARN_ON_ONCE(!VALID_PAGE(fault_mmu->root.hpa)); > + I've been updating the patches as per your suggestions. And I suddenly realized that when fault->nested_page_fault=false with nested EPT, fault_mmu->root.hpa is always unset. fault_mmu->root.hpa is just meaningless when fault_mmu is not vcpu->arch.mmu. I will add it as one of the reasons for replacing the argument with KVM_MMU_ROOT_XXX. > /* > * Invalidate the TLB entry for the faulting address, if it exists, > * else the access will fault indefinitely (and to emulate hardware). >
