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    SubjectRe: [PATCH v2 31/32] KVM: nVMX: Don't flush TLB on nested VM transition with EPT enabled
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    On 17/03/20 05:52, Sean Christopherson wrote:
    > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
    > index d816f1366943..a77eab5b0e8a 100644
    > --- a/arch/x86/kvm/vmx/nested.c
    > +++ b/arch/x86/kvm/vmx/nested.c
    > @@ -1123,7 +1123,7 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool ne
    > }
    >
    > if (!nested_ept)
    > - kvm_mmu_new_cr3(vcpu, cr3, false);
    > + kvm_mmu_new_cr3(vcpu, cr3, enable_ept);

    Even if enable_ept == false, we could have already scheduled or flushed
    the TLB soon due to one of 1) nested_vmx_transition_tlb_flush 2)
    vpid_sync_context in prepare_vmcs02 3) the processor doing it for
    !enable_vpid.

    So for !enable_ept only KVM_REQ_MMU_SYNC is needed, not
    KVM_REQ_TLB_FLUSH_CURRENT I think. Worth adding a TODO?

    Paolo

    > vcpu->arch.cr3 = cr3;
    > kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);
    > -- 2.24.1

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