Merge branch 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 paravirt changes from Ingo Molnar:
 "Hypervisor signature detection cleanup and fixes - the goal is to make
  KVM guests run better on MS/Hyperv and to generalize and factor out
  the code a bit"

* 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Correctly detect hypervisor
  x86, kvm: Switch to use hypervisor_cpuid_base()
  xen: Switch to use hypervisor_cpuid_base()
  x86: Introduce hypervisor_cpuid_base()

4 files changed, 26 insertions, 31 deletions

diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index 2d4b5e6..e42f758 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -33,7 +33,7 @@ struct hypervisor_x86 {
 	const char	*name;
 
 	/* Detection routine */
-	bool		(*detect)(void);
+	uint32_t	(*detect)(void);
 
 	/* Adjust CPU feature bits (run once per CPU) */
 	void		(*set_cpu_features)(struct cpuinfo_x86 *);
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 695399f..0644129 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)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 4c2d31d..987c75e 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -942,6 +942,21 @@ extern int set_tsc_mode(unsigned int val);
 
 extern u16 amd_get_nb_id(int cpu);
 
+static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
+{
+	uint32_t base, eax, signature[3];
+
+	for (base = 0x40000000; base < 0x40010000; base += 0x100) {
+		cpuid(base, &eax, &signature[0], &signature[1], &signature[2]);
+
+		if (!memcmp(sig, signature, 12) &&
+		    (leaves == 0 || ((eax - base) >= leaves)))
+			return base;
+	}
+
+	return 0;
+}
+
 extern unsigned long arch_align_stack(unsigned long sp);
 extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
 
diff --git a/arch/x86/include/asm/xen/hypervisor.h b/arch/x86/include/asm/xen/hypervisor.h
index 125f344..d866959 100644
--- a/arch/x86/include/asm/xen/hypervisor.h
+++ b/arch/x86/include/asm/xen/hypervisor.h
@@ -40,21 +40,7 @@ extern struct start_info *xen_start_info;
 
 static inline uint32_t xen_cpuid_base(void)
 {
-	uint32_t base, eax, ebx, ecx, edx;
-	char signature[13];
-
-	for (base = 0x40000000; base < 0x40010000; base += 0x100) {
-		cpuid(base, &eax, &ebx, &ecx, &edx);
-		*(uint32_t *)(signature + 0) = ebx;
-		*(uint32_t *)(signature + 4) = ecx;
-		*(uint32_t *)(signature + 8) = edx;
-		signature[12] = 0;
-
-		if (!strcmp("XenVMMXenVMM", signature) && ((eax - base) >= 2))
-			return base;
-	}
-
-	return 0;
+	return hypervisor_cpuid_base("XenVMMXenVMM", 2);
 }
 
 #ifdef CONFIG_XEN