x86: Clean up the hypervisor layer

Clean up the hypervisor layer and the hypervisor drivers, using an ops
structure instead of an enumeration with if statements.

The identity of the hypervisor, if needed, can be tested by testing
the pointer value in x86_hyper.

The MS-HyperV private state is moved into a normal global variable
(it's per-system state, not per-CPU state).  Being a normal bss
variable, it will be left at all zero on non-HyperV platforms, and so
can generally be tested for HyperV-specific features without
additional qualification.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Greg KH <greg@kroah.com>
Cc: Hank Janssen <hjanssen@microsoft.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Ky Srinivasan <ksrinivasan@novell.com>
LKML-Reference: <4BE49778.6060800@zytor.com>

3 files changed, 78 insertions, 65 deletions

diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
index de3f4e0ce8e..87381759d3c 100644
--- a/arch/x86/kernel/cpu/hypervisor.c
+++ b/arch/x86/kernel/cpu/hypervisor.c
@@ -22,40 +22,52 @@
  */
 
 #include <asm/processor.h>
-#include <asm/vmware.h>
-#include <asm/mshyperv.h>
 #include <asm/hypervisor.h>
 
-static inline void __cpuinit
-detect_hypervisor_vendor(struct cpuinfo_x86 *c)
+/*
+ * Hypervisor detect order.  This is specified explicitly here because
+ * some hypervisors might implement compatibility modes for other
+ * hypervisors and therefore need to be detected in specific sequence.
+ */
+static const __initconst struct hypervisor_x86 * const hypervisors[] =
 {
-	if (vmware_platform())
-		c->x86_hyper_vendor = X86_HYPER_VENDOR_VMWARE;
-	else if (ms_hyperv_platform())
-		c->x86_hyper_vendor = X86_HYPER_VENDOR_MSFT;
-	else
-		c->x86_hyper_vendor = X86_HYPER_VENDOR_NONE;
-}
+	&x86_hyper_vmware,
+	&x86_hyper_ms_hyperv,
+};
 
-static inline void __cpuinit
-hypervisor_set_feature_bits(struct cpuinfo_x86 *c)
+const struct hypervisor_x86 *x86_hyper;
+
+static inline void __init
+detect_hypervisor_vendor(void)
 {
-	if (boot_cpu_data.x86_hyper_vendor == X86_HYPER_VENDOR_VMWARE)
-		vmware_set_feature_bits(c);
-	else if (boot_cpu_data.x86_hyper_vendor == X86_HYPER_VENDOR_MSFT)
-		ms_hyperv_set_feature_bits(c);
-	return;
+	const struct hypervisor_x86 *h, * const *p;
+
+	for (p = hypervisors; p < hypervisors + ARRAY_SIZE(hypervisors); p++) {
+		h = *p;
+		if (h->detect()) {
+			x86_hyper = h;
+			printk(KERN_INFO "Hypervisor detected: %s\n", h->name);
+			break;
+		}
+	}
 }
 
 void __cpuinit init_hypervisor(struct cpuinfo_x86 *c)
 {
-	detect_hypervisor_vendor(c);
-	hypervisor_set_feature_bits(c);
+	if (x86_hyper && x86_hyper->set_cpu_features)
+		x86_hyper->set_cpu_features(c);
 }
 
 void __init init_hypervisor_platform(void)
 {
+
+	detect_hypervisor_vendor();
+
+	if (!x86_hyper)
+		return;
+
 	init_hypervisor(&boot_cpu_data);
-	if (boot_cpu_data.x86_hyper_vendor == X86_HYPER_VENDOR_VMWARE)
-		vmware_platform_setup();
+
+	if (x86_hyper->init_platform)
+		x86_hyper->init_platform();
 }
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index a58d8e64fc7..5969c3ee318 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -12,45 +12,42 @@
 
 #include <linux/types.h>
 #include <asm/processor.h>
+#include <asm/hypervisor.h>
 #include <asm/hyperv.h>
 #include <asm/mshyperv.h>
 
+struct ms_hyperv_info ms_hyperv;
 
-int ms_hyperv_platform(void)
+static bool __init ms_hyperv_platform(void)
 {
-	u32 eax, ebx, ecx, edx;
-	char hyp_signature[13];
+	u32 eax;
+	u32 hyp_signature[3];
 
-	cpuid(1, &eax, &ebx, &ecx, &edx);
-	if (!(ecx & HYPERV_HYPERVISOR_PRESENT_BIT))
-		return 0;
+	if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
+		return false;
 
-	cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, &eax, &ebx, &ecx, &edx);
-	*(u32 *)(hyp_signature + 0) = ebx;
-	*(u32 *)(hyp_signature + 4) = ecx;
-	*(u32 *)(hyp_signature + 8) = edx;
+	cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
+	      &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
 
-	if ((eax < HYPERV_CPUID_MIN) || (memcmp("Microsoft Hv", hyp_signature, 12)))
-		return 0;
-	return 1;
+	return eax >= HYPERV_CPUID_MIN &&
+		eax <= HYPERV_CPUID_MAX &&
+		!memcmp("Microsoft Hv", hyp_signature, 12);
 }
 
-void __cpuinit ms_hyperv_set_feature_bits(struct cpuinfo_x86 *c)
+static void __init ms_hyperv_init_platform(void)
 {
-	u32 eax, ebx, ecx, edx;
-
-	c->x86_hyper_features = 0;
 	/*
-	 * Extract the features, recommendations etc.
-	 * The first 9 bits will be used to track hypervisor features.
-	 * The next 6 bits will be used to track the hypervisor
-	 * recommendations.
+	 * Extract the features and hints
 	 */
-	cpuid(HYPERV_CPUID_FEATURES, &eax, &ebx, &ecx, &edx);
-	c->x86_hyper_features |= (eax & 0x1ff);
+	ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
+	ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
 
-	cpuid(HYPERV_CPUID_ENLIGHTMENT_INFO, &eax, &ebx, &ecx, &edx);
-	c->x86_hyper_features |= ((eax & 0x3f) << 9);
-	printk(KERN_INFO "Detected HyperV with features: %x\n",
-		c->x86_hyper_features);
+	printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
+	       ms_hyperv.features, ms_hyperv.hints);
 }
+
+const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
+	.name			= "Microsoft HyperV",
+	.detect			= ms_hyperv_platform,
+	.init_platform		= ms_hyperv_init_platform,
+};
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 1cbed97b59c..46a5b5d3ba5 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -23,8 +23,8 @@
 
 #include <linux/dmi.h>
 #include <asm/div64.h>
-#include <asm/vmware.h>
 #include <asm/x86_init.h>
+#include <asm/hypervisor.h>
 
 #define CPUID_VMWARE_INFO_LEAF	0x40000000
 #define VMWARE_HYPERVISOR_MAGIC	0x564D5868
@@ -64,7 +64,7 @@ static unsigned long vmware_get_tsc_khz(void)
 	return tsc_hz;
 }
 
-void __init vmware_platform_setup(void)
+static void __init vmware_platform_setup(void)
 {
 	uint32_t eax, ebx, ecx, edx;
 
@@ -82,24 +82,21 @@ void __init vmware_platform_setup(void)
  * serial key should be enough, as this will always have a VMware
  * specific string when running under VMware hypervisor.
  */
-int vmware_platform(void)
+static bool __init vmware_platform(void)
 {
 	if (cpu_has_hypervisor) {
-		unsigned int eax, ebx, ecx, edx;
-		char hyper_vendor_id[13];
-
-		cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &ebx, &ecx, &edx);
-		memcpy(hyper_vendor_id + 0, &ebx, 4);
-		memcpy(hyper_vendor_id + 4, &ecx, 4);
-		memcpy(hyper_vendor_id + 8, &edx, 4);
-		hyper_vendor_id[12] = '\0';
-		if (!strcmp(hyper_vendor_id, "VMwareVMware"))
-			return 1;
+		unsigned int eax;
+		unsigned int hyper_vendor_id[3];
+
+		cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
+		      &hyper_vendor_id[1], &hyper_vendor_id[2]);
+		if (!memcmp(hyper_vendor_id, "VMwareVMware", 12))
+			return true;
 	} else if (dmi_available && dmi_name_in_serial("VMware") &&
 		   __vmware_platform())
-		return 1;
+		return true;
 
-	return 0;
+	return false;
 }
 
 /*
@@ -114,8 +111,15 @@ int vmware_platform(void)
  * so that the kernel could just trust the hypervisor with providing a
  * reliable virtual TSC that is suitable for timekeeping.
  */
-void __cpuinit vmware_set_feature_bits(struct cpuinfo_x86 *c)
+static void __cpuinit vmware_set_cpu_features(struct cpuinfo_x86 *c)
 {
 	set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
 	set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);
 }
+
+const __refconst struct hypervisor_x86 x86_hyper_vmware = {
+	.name			= "VMware",
+	.detect			= vmware_platform,
+	.set_cpu_features	= vmware_set_cpu_features,
+	.init_platform		= vmware_platform_setup,
+};