linux-kernel - [PATCH 9/9] KVM: x86: Disable intercept for Intel processor trace MSRs

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Message-Id: <1508156051-5024-1-git-send-email-luwei.kang@intel.com>
Date:   Mon, 16 Oct 2017 20:14:11 +0800
From:   Luwei Kang <luwei.kang@...el.com>
To:     kvm@...r.kernel.org
Cc:     pbonzini@...hat.com, rkrcmar@...hat.com, tglx@...utronix.de,
        mingo@...hat.com, hpa@...or.com, x86@...nel.org,
        linux-kernel@...r.kernel.org,
        Chao Peng <chao.p.peng@...ux.intel.com>,
        Luwei Kang <luwei.kang@...el.com>
Subject: [PATCH 9/9] KVM: x86: Disable intercept for Intel processor trace MSRs

From: Chao Peng <chao.p.peng@...ux.intel.com>

Trap for Intel processor trace is none sense. Pass through to
guest directly.

Signed-off-by: Chao Peng <chao.p.peng@...ux.intel.com>
Signed-off-by: Luwei Kang <luwei.kang@...el.com>
---
 arch/x86/kvm/vmx.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3c9ce3e..58606ce 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7076,6 +7076,20 @@ static __init int hardware_setup(void)
 	if (pt_mode == PT_MODE_GUEST)
 		pt_register_virt_ops(&pt_virt_ops);
 
+	if (pt_mode == PT_MODE_GUEST || pt_mode == PT_MODE_HOST_GUEST) {
+		u32 i, eax, ebx, ecx, edx;
+
+		cpuid_count(0x14, 1, &eax, &ebx, &ecx, &edx);
+		vmx_disable_intercept_for_msr(MSR_IA32_RTIT_CTL, false);
+		vmx_disable_intercept_for_msr(MSR_IA32_RTIT_STATUS, false);
+		vmx_disable_intercept_for_msr(MSR_IA32_RTIT_OUTPUT_BASE, false);
+		vmx_disable_intercept_for_msr(MSR_IA32_RTIT_OUTPUT_MASK, false);
+		vmx_disable_intercept_for_msr(MSR_IA32_RTIT_CR3_MATCH, false);
+		for (i = 0; i < (eax & 0x7); i++)
+			vmx_disable_intercept_for_msr(MSR_IA32_RTIT_ADDR0_A + i,
+									false);
+	}
+
 	return alloc_kvm_area();
 
 out:
-- 
1.8.3.1