linux-kernel - [PATCH 10/10] KVM: VMX: Fold __vmx_flush_tlb() into vmx_flush

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Date:   Thu, 20 Feb 2020 12:43:56 -0800
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 10/10] KVM: VMX: Fold __vmx_flush_tlb() into vmx_flush_tlb()

Fold __vmx_flush_tlb() into its sole caller, vmx_flush_tlb(), now that
all call sites that previously bounced through __vmx_flush_tlb() to
force the INVVPID path instead call vpid_sync_context() directly.

Opportunistically add a comment to explain why INVEPT is necessary when
EPT is enabled, even if VPID is disabled.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/vmx/vmx.h | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 6e0ca57cc41c..6204fa5897bb 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -501,23 +501,25 @@ static inline struct vmcs *alloc_vmcs(bool shadow)
 
 u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa);
 
-static inline void __vmx_flush_tlb(struct kvm_vcpu *vcpu, int vpid)
+static inline void vmx_flush_tlb(struct kvm_vcpu *vcpu)
 {
+	/*
+	 * INVEPT must be issued when EPT is enabled, irrespective of VPID, as
+	 * the CPU is not required to invalidate GPA->HPA mappings on VM-Entry,
+	 * even if VPID is disabled.  GPA->HPA mappings are associated with the
+	 * root EPT structure and not any particular VPID (INVVPID is also not
+	 * required to invalidate GPA->HPA mappings).
+	 */
 	if (enable_ept) {
 		if (!VALID_PAGE(vcpu->arch.mmu->root_hpa))
 			return;
 		ept_sync_context(construct_eptp(vcpu,
 						vcpu->arch.mmu->root_hpa));
 	} else {
-		vpid_sync_context(vpid);
+		vpid_sync_context(to_vmx(vcpu)->vpid);
 	}
 }
 
-static inline void vmx_flush_tlb(struct kvm_vcpu *vcpu)
-{
-	__vmx_flush_tlb(vcpu, to_vmx(vcpu)->vpid);
-}
-
 static inline void decache_tsc_multiplier(struct vcpu_vmx *vmx)
 {
 	vmx->current_tsc_ratio = vmx->vcpu.arch.tsc_scaling_ratio;
-- 
2.24.1