linux-kernel - [PATCH 5/9] KVM: VMX: simplify rdtscp handling in vmx_cpuid

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Date:	Fri, 21 Aug 2015 12:50:07 +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 5/9] KVM: VMX: simplify rdtscp handling in vmx_cpuid_update()

if vmx_rdtscp_supported() is true SECONDARY_EXEC_RDTSCP must
have already been set in current vmcs by
vmx_secondary_exec_control()

Signed-off-by: Xiao Guangrong <guangrong.xiao@...ux.intel.com>
---
 arch/x86/kvm/vmx.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f7a721e..99f638e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8668,16 +8668,15 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 	vmx->rdtscp_enabled = false;
 	if (vmx_rdtscp_supported()) {
 		exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
-		if (exec_control & SECONDARY_EXEC_RDTSCP) {
-			best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
-			if (best && (best->edx & bit(X86_FEATURE_RDTSCP)))
-				vmx->rdtscp_enabled = true;
-			else {
-				exec_control &= ~SECONDARY_EXEC_RDTSCP;
-				vmcs_write32(SECONDARY_VM_EXEC_CONTROL,
-						exec_control);
-			}
+		best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
+		if (best && (best->edx & bit(X86_FEATURE_RDTSCP)))
+			vmx->rdtscp_enabled = true;
+		else {
+			exec_control &= ~SECONDARY_EXEC_RDTSCP;
+			vmcs_write32(SECONDARY_VM_EXEC_CONTROL,
+					exec_control);
 		}
+
 		if (nested && !vmx->rdtscp_enabled)
 			vmx->nested.nested_vmx_secondary_ctls_high &=
 				~SECONDARY_EXEC_RDTSCP;
-- 
2.4.3

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