From ae87afbf83fc1d13734f5ea45ff7005bcd77dfcb Mon Sep 17 00:00:00 2001
From: Cyrill Gorcunov <gorcunov@gmail.com>
Date: Mon, 5 Jul 2010 21:10:48 +0400
Subject: [PATCH] kvm: Check for SVM extension being supported for AMD cpus

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
 include/kvm/cpufeature.h |  1 +
 kvm.c                    | 26 ++++++++++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/include/kvm/cpufeature.h b/include/kvm/cpufeature.h
index 4f566df..92abb87 100644
--- a/include/kvm/cpufeature.h
+++ b/include/kvm/cpufeature.h
@@ -13,6 +13,7 @@
  * CPUID flags we need to deal with
  */
 #define KVM__X86_FEATURE_VMX		5	/* Hardware virtualization */
+#define KVM__X86_FEATURE_SVM		2	/* Secure virtual machine */
 #define KVM__X86_FEATURE_XSAVE		26	/* XSAVE/XRSTOR/XSETBV/XGETBV */
 
 #define cpu_feature_disable(reg, feature)	\
diff --git a/kvm.c b/kvm.c
index f290f8c..4d1efaa 100644
--- a/kvm.c
+++ b/kvm.c
@@ -137,13 +137,35 @@ void kvm__delete(struct kvm *self)
 static bool kvm__cpu_supports_vm(void)
 {
 	struct cpuid_regs regs;
+	bool ret = false;
 
 	regs	= (struct cpuid_regs) {
-		.eax		= 1,
+		.eax		= 0,
 	};
 	host_cpuid(&regs);
 
-	return regs.ecx & (1 << KVM__X86_FEATURE_VMX);
+	switch (regs.ebx) {
+	case CPUID_VENDOR_INTEL_1:
+		if (regs.eax < 1)
+			return false;
+		regs = (struct cpuid_regs) { .eax = 1 };
+		host_cpuid(&regs);
+		if (regs.ecx & (1 << KVM__X86_FEATURE_VMX))
+			ret = true;
+		break;
+	case CPUID_VENDOR_AMD_1:
+		regs = (struct cpuid_regs) { .eax = 0x80000000 };
+		host_cpuid(&regs);
+		if (regs.eax < 0x80000001)
+			return false;
+		regs = (struct cpuid_regs) { .eax = 0x80000001 };
+		host_cpuid(&regs);
+		if (regs.ecx & (1 << KVM__X86_FEATURE_SVM))
+			ret = true;
+		break;
+	}
+
+	return ret;
 }
 
 struct kvm *kvm__init(const char *kvm_dev)