linux-kernel - [PATCH v2 2/2] KVM: VMX: Do not perform emulation for INVD intercept

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Date:   Thu, 24 Sep 2020 13:41:58 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     kvm@...r.kernel.org, x86@...nel.org, linux-kernel@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        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>,
        Brijesh Singh <brijesh.singh@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH v2 2/2] KVM: VMX: Do not perform emulation for INVD intercept

From: Tom Lendacky <thomas.lendacky@....com>

The INVD instruction is emulated as a NOP, just skip the instruction
instead.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
---
 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 8646a797b7a8..f8075d3acf9c 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5148,7 +5148,8 @@ static int handle_vmcall(struct kvm_vcpu *vcpu)
 
 static int handle_invd(struct kvm_vcpu *vcpu)
 {
-	return kvm_emulate_instruction(vcpu, 0);
+	/* Treat an INVD instruction as a NOP and just skip it. */
+	return kvm_skip_emulated_instruction(vcpu);
 }
 
 static int handle_invlpg(struct kvm_vcpu *vcpu)
-- 
2.28.0