[Xen-devel] [PATCH v4 01/11] x86/acpi: add a common interface for x86 cpu matching

[Wei Wang <wei.w.wang@xxxxxxxxx>]

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

v4 changes:
None.

Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx>
---
 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


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