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-rw-r--r--arch/x86/kernel/kvm.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 6dd802c6d780..0823003770fc 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -500,6 +500,33 @@ void __init kvm_guest_init(void)
#endif
}
+static noinline uint32_t __kvm_cpuid_base(void)
+{
+ if (boot_cpu_data.cpuid_level < 0)
+ return 0; /* So we don't blow up on old processors */
+
+ if (cpu_has_hypervisor)
+ return hypervisor_cpuid_base("KVMKVMKVM\0\0\0", 0);
+
+ return 0;
+}
+
+static inline uint32_t kvm_cpuid_base(void)
+{
+ static int kvm_cpuid_base = -1;
+
+ if (kvm_cpuid_base == -1)
+ kvm_cpuid_base = __kvm_cpuid_base();
+
+ return kvm_cpuid_base;
+}
+
+bool kvm_para_available(void)
+{
+ return kvm_cpuid_base() != 0;
+}
+EXPORT_SYMBOL_GPL(kvm_para_available);
+
static uint32_t __init kvm_detect(void)
{
return kvm_cpuid_base();