linux-kernel - [patch v2 7/8] KVM: x86: add Intel PT msr RTIT

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Date:   Tue, 31 Oct 2017 06:05:16 +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 v2 7/8] KVM: x86: add Intel PT msr RTIT_CTL read/write

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

L1 hypervisor can't get the capability of "TraceEn can be
set in VMX operation"(IA32_VMX_MISC[14]=0) and any attempt
to set IA32_RTIT_CTL.TraceEn in VMX operation using WRMSR
will cause a general-protection exception if IA32_VMX_MISC[14]
is 0. So we need to leave out write this msr in L1 VMX
operation.

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 | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 091120e..8f61a8d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -936,6 +936,7 @@ static void vmx_get_segment(struct kvm_vcpu *vcpu,
 static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked);
 static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12,
 					    u16 error_code);
+static bool vmx_pt_supported(void);
 
 static DEFINE_PER_CPU(struct vmcs *, vmxarea);
 static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
@@ -3384,6 +3385,11 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 		msr_info->data = vcpu->arch.ia32_xss;
 		break;
+	case MSR_IA32_RTIT_CTL:
+		if (!vmx_pt_supported())
+			return 1;
+		msr_info->data = vmcs_read64(GUEST_IA32_RTIT_CTL);
+		break;
 	case MSR_TSC_AUX:
 		if (!msr_info->host_initiated &&
 		    !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
@@ -3508,6 +3514,11 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		else
 			clear_atomic_switch_msr(vmx, MSR_IA32_XSS);
 		break;
+	case MSR_IA32_RTIT_CTL:
+		if (!vmx_pt_supported() || to_vmx(vcpu)->nested.vmxon)
+			return 1;
+		vmcs_write64(GUEST_IA32_RTIT_CTL, data);
+		break;
 	case MSR_TSC_AUX:
 		if (!msr_info->host_initiated &&
 		    !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
-- 
1.8.3.1