linux-kernel - [PATCH v2 5/8] KVM: VMX: simplify invpcid handling in vmx_cpuid

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Date:	Wed,  9 Sep 2015 14:05:54 +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 v2 5/8] KVM: VMX: simplify invpcid handling in vmx_cpuid_update()

If vmx_invpcid_supported() is true, second execution control
filed must be supported and SECONDARY_EXEC_ENABLE_INVPCID
must have already been set in current vmcs by
vmx_secondary_exec_control()

If vmx_invpcid_supported() is false, no need to clear
SECONDARY_EXEC_ENABLE_INVPCID

Signed-off-by: Xiao Guangrong <guangrong.xiao@...ux.intel.com>
---
 arch/x86/kvm/vmx.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index bcc69de..97e3340 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8695,19 +8695,12 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 	/* Exposing INVPCID only when PCID is exposed */
 	best = kvm_find_cpuid_entry(vcpu, 0x7, 0);
 	if (vmx_invpcid_supported() &&
-	    best && (best->ebx & bit(X86_FEATURE_INVPCID)) &&
-	    guest_cpuid_has_pcid(vcpu)) {
+	    (!best || !(best->ebx & bit(X86_FEATURE_INVPCID)) ||
+	    !guest_cpuid_has_pcid(vcpu))) {
 		exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
-		exec_control |= SECONDARY_EXEC_ENABLE_INVPCID;
-		vmcs_write32(SECONDARY_VM_EXEC_CONTROL,
-			     exec_control);
-	} else {
-		if (cpu_has_secondary_exec_ctrls()) {
-			exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
-			exec_control &= ~SECONDARY_EXEC_ENABLE_INVPCID;
-			vmcs_write32(SECONDARY_VM_EXEC_CONTROL,
-				     exec_control);
-		}
+		exec_control &= ~SECONDARY_EXEC_ENABLE_INVPCID;
+		vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);
+
 		if (best)
 			best->ebx &= ~bit(X86_FEATURE_INVPCID);
 	}
-- 
2.4.3

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