Messages in this thread | | | From | Lai Jiangshan <> | Date | Fri, 3 Feb 2023 22:51:15 +0800 | Subject | Re: [PATCH 1/7] kvm: x86/mmu: Use KVM_MMU_ROOT_XXX for kvm_mmu_invalidate_gva() |
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On Thu, Feb 2, 2023 at 9:21 AM Sean Christopherson <seanjc@google.com> 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). >
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