linux-kernel - [PATCH 9/9] KVM: VMX: drop rdtscp

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Date:	Fri, 21 Aug 2015 12:50:11 +0800
From:	Xiao Guangrong <guangrong.xiao@...ux.intel.com>
To:	pbonzini@...hat.com
Cc:	gleb@...nel.org, mtosatti@...hat.com, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Xiao Guangrong <guangrong.xiao@...ux.intel.com>
Subject: [PATCH 9/9] KVM: VMX: drop rdtscp_enabled field

Check cpuid bit instead of it

Signed-off-by: Xiao Guangrong <guangrong.xiao@...ux.intel.com>
---
 arch/x86/kvm/cpuid.h |  8 ++++++++
 arch/x86/kvm/vmx.c   | 19 ++++++-------------
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index aed7bfe..d434ee9 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -141,4 +141,12 @@ static inline bool guest_cpuid_has_pcommit(struct kvm_vcpu *vcpu)
 	best = kvm_find_cpuid_entry(vcpu, 7, 0);
 	return best && (best->ebx & bit(X86_FEATURE_PCOMMIT));
 }
+
+static inline bool guest_cpuid_has_rdtscp(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpuid_entry2 *best;
+
+	best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
+	return best && (best->edx & bit(X86_FEATURE_RDTSCP));
+}
 #endif
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 58f7b89..d50fb48 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -532,8 +532,6 @@ struct vcpu_vmx {
 	s64 vnmi_blocked_time;
 	u32 exit_reason;
 
-	bool rdtscp_enabled;
-
 	/* Posted interrupt descriptor */
 	struct pi_desc pi_desc;
 
@@ -2207,7 +2205,7 @@ static void setup_msrs(struct vcpu_vmx *vmx)
 		if (index >= 0)
 			move_msr_up(vmx, index, save_nmsrs++);
 		index = __find_msr_index(vmx, MSR_TSC_AUX);
-		if (index >= 0 && vmx->rdtscp_enabled)
+		if (index >= 0 && guest_cpuid_has_rdtscp(&vmx->vcpu))
 			move_msr_up(vmx, index, save_nmsrs++);
 		/*
 		 * MSR_STAR is only needed on long mode guests, and only
@@ -2674,7 +2672,7 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		msr_info->data = vcpu->arch.ia32_xss;
 		break;
 	case MSR_TSC_AUX:
-		if (!to_vmx(vcpu)->rdtscp_enabled)
+		if (!guest_cpuid_has_rdtscp(vcpu))
 			return 1;
 		/* Otherwise falls through */
 	default:
@@ -2780,7 +2778,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			clear_atomic_switch_msr(vmx, MSR_IA32_XSS);
 		break;
 	case MSR_TSC_AUX:
-		if (!vmx->rdtscp_enabled)
+		if (!guest_cpuid_has_rdtscp(vcpu))
 			return 1;
 		/* Check reserved bit, higher 32 bits should be zero */
 		if ((data >> 32) != 0)
@@ -8665,15 +8663,10 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	u32 clear_exe_ctrl = 0;
 
-	vmx->rdtscp_enabled = false;
-	if (vmx_rdtscp_supported()) {
-		best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
-		if (best && (best->edx & bit(X86_FEATURE_RDTSCP)))
-			vmx->rdtscp_enabled = true;
-		else
-			clear_exe_ctrl |= SECONDARY_EXEC_RDTSCP;
+	if (vmx_rdtscp_supported() && !guest_cpuid_has_rdtscp(vcpu)) {
+		clear_exe_ctrl |= SECONDARY_EXEC_RDTSCP;
 
-		if (nested && !vmx->rdtscp_enabled)
+		if (nested)
 			vmx->nested.nested_vmx_secondary_ctls_high &=
 				~SECONDARY_EXEC_RDTSCP;
 	}
-- 
2.4.3

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