x86, kvm: Switch to use hypervisor_cpuid_base()

Switch to use hypervisor_cpuid_base() to detect KVM.

Cc: Gleb Natapov <gleb@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: http://lkml.kernel.org/r/1374742475-2485-3-git-send-email-jasowang@redhat.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 9 insertions, 15 deletions

diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 695399f2d5eb..0644129a5333 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -85,26 +85,20 @@ static inline long kvm_hypercall4(unsigned int nr, unsigned long p1,
         return ret;
 }
 
-static inline bool kvm_para_available(void)
+static inline uint32_t kvm_cpuid_base(void)
 {
-        unsigned int eax, ebx, ecx, edx;
-        char signature[13];
-
         if (boot_cpu_data.cpuid_level < 0)
-                return false;   /* So we don't blow up on old processors */
+                return 0;       /* So we don't blow up on old processors */
 
-        if (cpu_has_hypervisor) {
-                cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx);
-                memcpy(signature + 0, &ebx, 4);
-                memcpy(signature + 4, &ecx, 4);
-                memcpy(signature + 8, &edx, 4);
-                signature[12] = 0;
+        if (cpu_has_hypervisor)
+                return hypervisor_cpuid_base("KVMKVMKVM\0\0\0", 0);
 
-                if (strcmp(signature, "KVMKVMKVM") == 0)
-                        return true;
-        }
+        return 0;
+}
 
-        return false;
+static inline bool kvm_para_available(void)
+{
+        return kvm_cpuid_base() != 0;
 }
 
 static inline unsigned int kvm_arch_para_features(void)