[PATCH v3 01/11] x86/acpi: add a common interface for x86 cpu matching

[PATCH v3 01/11] x86/acpi: add a common interface for x86 cpu matching

[Wei Wang]

Add a common interface for matching the current cpu against an
array of x86_cpu_ids. Also change mwait-idle.c to use it.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
---
 xen/arch/x86/cpu/common.c       | 38 ++++++++++++++++++++++++++++++++++++++
 xen/arch/x86/cpu/mwait-idle.c   | 28 +++++++++++-----------------
 xen/include/asm-x86/processor.h | 10 ++++++++++
 3 files changed, 59 insertions(+), 17 deletions(-)

diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 53dbd84..e105aeb 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -637,3 +637,41 @@ void cpu_uninit(unsigned int cpu)
 {
 	cpumask_clear_cpu(cpu, &cpu_initialized);
 }
+
+/*
+ * x86_match_cpu - match the current CPU against an array of
+ * x86_cpu_ids
+ * @match: Pointer to array of x86_cpu_ids. Last entry terminated with
+ *         {}.
+ * Return the entry if the current CPU matches the entries in the
+ * passed x86_cpu_id match table. Otherwise NULL.  The match table
+ * contains vendor (X86_VENDOR_*), family, model and feature bits or
+ * respective wildcard entries.
+ *
+ * A typical table entry would be to match a specific CPU
+ * { X86_VENDOR_INTEL, 6, 0x12 }
+ * or to match a specific CPU feature
+ * { X86_FEATURE_MATCH(X86_FEATURE_FOOBAR) }
+ *
+ * This always matches against the boot cpu, assuming models and
+features are
+ * consistent over all CPUs.
+ */
+const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id table[])
+{
+	const struct x86_cpu_id *m;
+	const struct cpuinfo_x86 *c = &boot_cpu_data;
+
+	for (m = table; m->vendor | m->family | m->model | m->feature; m++) {
+		if (c->x86_vendor != m->vendor)
+			continue;
+		if (c->x86 != m->family)
+			continue;
+		if (c->x86_model != m->model)
+			continue;
+		if (!cpu_has(c, m->feature))
+			continue;
+		return m;
+	}
+	return NULL;
+}
diff --git a/xen/arch/x86/cpu/mwait-idle.c b/xen/arch/x86/cpu/mwait-idle.c
index 91b76ec..30cfc4c 100644
--- a/xen/arch/x86/cpu/mwait-idle.c
+++ b/xen/arch/x86/cpu/mwait-idle.c
@@ -689,12 +689,11 @@ static const struct idle_cpu idle_cpu_avn = {
 	.disable_promotion_to_c1e = 1,
 };
 
-#define ICPU(model, cpu) { 6, model, &idle_cpu_##cpu }
+#define ICPU(model, cpu) \
+    { X86_VENDOR_INTEL, 6, model, X86_FEATURE_MWAIT, \
+        &idle_cpu_##cpu}
 
-static struct intel_idle_id {
-	unsigned int family, model;
-	const struct idle_cpu *data;
-} intel_idle_ids[] __initdata = {
+static const struct x86_cpu_id intel_idle_ids[] __initconst = {
 	ICPU(0x1a, nehalem),
 	ICPU(0x1e, nehalem),
 	ICPU(0x1f, nehalem),
@@ -757,23 +756,18 @@ static void __init mwait_idle_state_table_update(void)
 static int __init mwait_idle_probe(void)
 {
 	unsigned int eax, ebx, ecx;
-	const struct intel_idle_id *id;
+	const struct x86_cpu_id *id;
 
-	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||
-	    !boot_cpu_has(X86_FEATURE_MWAIT) ||
-	    boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
-		return -ENODEV;
-
-	for (id = intel_idle_ids; id->family; ++id)
-		if (id->family == boot_cpu_data.x86 &&
-		    id->model == boot_cpu_data.x86_model)
-			break;
-	if (!id->family) {
+	id = x86_match_cpu(intel_idle_ids);
+	if (!id) {
 		pr_debug(PREFIX "does not run on family %d model %d\n",
 			 boot_cpu_data.x86, boot_cpu_data.x86_model);
 		return -ENODEV;
 	}
 
+	if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
+		return -ENODEV;
+
 	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
 
 	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
@@ -788,7 +782,7 @@ static int __init mwait_idle_probe(void)
 
 	pr_debug(PREFIX "MWAIT substates: %#x\n", mwait_substates);
 
-	icpu = id->data;
+	icpu = (const struct idle_cpu *)id->driver_data;
 	cpuidle_state_table = icpu->state_table;
 
 	if (boot_cpu_has(X86_FEATURE_ARAT))
diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index fb2c2fc..68cd92b 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -163,6 +163,14 @@ struct vcpu;
     pc;                                             \
 })
 
+struct x86_cpu_id {
+    uint16_t vendor;
+    uint16_t family;
+    uint16_t model;
+    uint16_t feature;   /* bit index */
+    const void *driver_data;
+};
+
 struct cpuinfo_x86 {
     __u8 x86;            /* CPU family */
     __u8 x86_vendor;     /* CPU vendor */
@@ -204,6 +212,8 @@ extern u32 cpuid_ext_features;
 /* Maximum width of physical addresses supported by the hardware */
 extern unsigned int paddr_bits;
 
+extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id table[]);
+
 extern void identify_cpu(struct cpuinfo_x86 *);
 extern void setup_clear_cpu_cap(unsigned int);
 extern void print_cpu_info(unsigned int cpu);
-- 
1.9.1

Re: [PATCH v3 01/11] x86/acpi: add a common interface for x86 cpu matching

[Jan Beulich]

>>> On 11.06.15 at 10:25, <wei.w.wang@intel.com> wrote:
> Add a common interface for matching the current cpu against an
> array of x86_cpu_ids. Also change mwait-idle.c to use it.
> 
> Signed-off-by: Wei Wang <wei.w.wang@intel.com>
> ---

There's a summary of the changes in v3 missing here (and it looks
like everywhere in the series). Putting change info in the overview
mail is nice, but the really useful thing for reviewing purposes is it
to be in each patch.

Jan