linux-kernel - [PATCH v2 04/10] KVM: VMX: Do Hyper-V TLB flush iff vCPU's EPTP hasn't been flushed

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Date:   Tue, 20 Oct 2020 14:56:07 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 04/10] KVM: VMX: Do Hyper-V TLB flush iff vCPU's EPTP hasn't been flushed

Combine the for-loops for Hyper-V TLB EPTP checking and flushing, and in
doing so skip flushes for vCPUs whose EPTP matches the target EPTP.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/vmx/vmx.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index bba6d91f1fe1..52cb9eec1db3 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -502,31 +502,23 @@ static int hv_remote_flush_tlb_with_range(struct kvm *kvm,
 
 	spin_lock(&kvm_vmx->ept_pointer_lock);
 
-	if (kvm_vmx->ept_pointers_match == EPT_POINTERS_CHECK) {
+	if (kvm_vmx->ept_pointers_match != EPT_POINTERS_MATCH) {
 		kvm_vmx->ept_pointers_match = EPT_POINTERS_MATCH;
 		kvm_vmx->hv_tlb_eptp = INVALID_PAGE;
 
 		kvm_for_each_vcpu(i, vcpu, kvm) {
 			tmp_eptp = to_vmx(vcpu)->ept_pointer;
-			if (!VALID_PAGE(tmp_eptp))
+			if (!VALID_PAGE(tmp_eptp) ||
+			    tmp_eptp == kvm_vmx->hv_tlb_eptp)
 				continue;
 
-			if (!VALID_PAGE(kvm_vmx->hv_tlb_eptp)) {
+			if (!VALID_PAGE(kvm_vmx->hv_tlb_eptp))
 				kvm_vmx->hv_tlb_eptp = tmp_eptp;
-			} else if (kvm_vmx->hv_tlb_eptp != tmp_eptp) {
+			else
 				kvm_vmx->ept_pointers_match
 					= EPT_POINTERS_MISMATCH;
-				break;
-			}
-		}
-	}
 
-	if (kvm_vmx->ept_pointers_match != EPT_POINTERS_MATCH) {
-		kvm_for_each_vcpu(i, vcpu, kvm) {
-			/* If ept_pointer is invalid pointer, bypass flush request. */
-			if (VALID_PAGE(to_vmx(vcpu)->ept_pointer))
-				ret |= hv_remote_flush_eptp(to_vmx(vcpu)->ept_pointer,
-							    range);
+			ret |= hv_remote_flush_eptp(tmp_eptp, range);
 		}
 	} else if (VALID_PAGE(kvm_vmx->hv_tlb_eptp)) {
 		ret = hv_remote_flush_eptp(kvm_vmx->hv_tlb_eptp, range);
-- 
2.28.0