cpu: Add model resolution support to CPUClass

Introduce CPUClass::class_by_name and add a default implementation.
Hook up the alpha and ppc implementations.

Introduce a wrapper function cpu_class_by_name().
Signed-off-by: NAndreas Färber <afaerber@suse.de>

include/qom/cpu.h

@@ -40,6 +40,8 @@ typedef struct CPUState CPUState;
 
 /**
  * CPUClass:
+ * @class_by_name: Callback to map -cpu command line model name to an
+ * instantiatable CPU type.
  * @reset: Callback to reset the #CPUState to its initial state.
  *
  * Represents a CPU family or model.
@@ -49,6 +51,8 @@ typedef struct CPUClass {
     DeviceClass parent_class;
     /*< public >*/
 
+    ObjectClass *(*class_by_name)(const char *cpu_model);
+
     void (*reset)(CPUState *cpu);
 } CPUClass;
 
@@ -107,6 +111,17 @@ struct CPUState {
  */
 void cpu_reset(CPUState *cpu);
 
+/**
+ * cpu_class_by_name:
+ * @typename: The CPU base type.
+ * @cpu_model: The model string without any parameters.
+ *
+ * Looks up a CPU #ObjectClass matching name @cpu_model.
+ *
+ * Returns: A #CPUClass or %NULL if not matching class is found.
+ */
+ObjectClass *cpu_class_by_name(const char *typename, const char *cpu_model);
+
 /**
  * qemu_cpu_has_work:
  * @cpu: The vCPU to check.

qom/cpu.c

@@ -34,11 +34,24 @@ static void cpu_common_reset(CPUState *cpu)
 {
 }
 
+ObjectClass *cpu_class_by_name(const char *typename, const char *cpu_model)
+{
+    CPUClass *cc = CPU_CLASS(object_class_by_name(typename));
+
+    return cc->class_by_name(cpu_model);
+}
+
+static ObjectClass *cpu_common_class_by_name(const char *cpu_model)
+{
+    return NULL;
+}
+
 static void cpu_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     CPUClass *k = CPU_CLASS(klass);
 
+    k->class_by_name = cpu_common_class_by_name;
     k->reset = cpu_common_reset;
     dc->no_user = 1;
 }

target-alpha/cpu.c

@@ -244,6 +244,13 @@ static void alpha_cpu_initfn(Object *obj)
     env->fen = 1;
 }
 
+static void alpha_cpu_class_init(ObjectClass *oc, void *data)
+{
+    CPUClass *cc = CPU_CLASS(oc);
+
+    cc->class_by_name = alpha_cpu_class_by_name;
+}
+
 static const TypeInfo alpha_cpu_type_info = {
     .name = TYPE_ALPHA_CPU,
     .parent = TYPE_CPU,
@@ -251,6 +258,7 @@ static const TypeInfo alpha_cpu_type_info = {
     .instance_init = alpha_cpu_initfn,
     .abstract = true,
     .class_size = sizeof(AlphaCPUClass),
+    .class_init = alpha_cpu_class_init,
 };
 
 static void alpha_cpu_register_types(void)

target-ppc/translate_init.c

@@ -10578,6 +10578,8 @@ static void ppc_cpu_class_init(ObjectClass *oc, void *data)
 
     pcc->parent_reset = cc->reset;
     cc->reset = ppc_cpu_reset;
+
+    cc->class_by_name = ppc_cpu_class_by_name;
 }
 
 static const TypeInfo ppc_cpu_type_info = {