2020-10-28 21:37:30

by Sean Christopherson

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Subject: [PATCH v3 07/11] KVM: VMX: Don't invalidate hv_tlb_eptp if the new EPTP matches

Don't invalidate the common EPTP, and thus trigger rechecking of EPTPs
across all vCPUs, if the new EPTP matches the old/common EPTP. In all
likelihood this is a meaningless optimization, but there are (uncommon)
scenarios where KVM can reload the same EPTP.

Reviewed-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
---
arch/x86/kvm/vmx/vmx.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 25a714cda662..4d9bc0d3a929 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3072,7 +3072,8 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,
if (kvm_x86_ops.tlb_remote_flush) {
spin_lock(&to_kvm_vmx(kvm)->ept_pointer_lock);
to_vmx(vcpu)->ept_pointer = eptp;
- to_kvm_vmx(kvm)->hv_tlb_eptp = INVALID_PAGE;
+ if (eptp != to_kvm_vmx(kvm)->hv_tlb_eptp)
+ to_kvm_vmx(kvm)->hv_tlb_eptp = INVALID_PAGE;
spin_unlock(&to_kvm_vmx(kvm)->ept_pointer_lock);
}

--
2.28.0