cpu: Register VMStateDescription through CPUState

In comparison to DeviceClass::vmsd, CPU VMState is split in two,
"cpu_common" and "cpu", and uses cpu_index as instance_id instead of -1.
Therefore add a CPU-specific CPUClass::vmsd field.

Unlike the legacy CPUArchState registration, rather register CPUState.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

exec.c

@@ -219,7 +219,7 @@ void cpu_exec_init_all(void)
 #endif
 }
 
-#if defined(CPU_SAVE_VERSION) && !defined(CONFIG_USER_ONLY)
+#if !defined(CONFIG_USER_ONLY)
 
 static int cpu_common_post_load(void *opaque, int version_id)
 {
@@ -266,6 +266,9 @@ CPUState *qemu_get_cpu(int index)
 void cpu_exec_init(CPUArchState *env)
 {
     CPUState *cpu = ENV_GET_CPU(env);
+#if !defined(CONFIG_USER_ONLY) && !defined(CPU_SAVE_VERSION)
+    CPUClass *cc = CPU_GET_CLASS(cpu);
+#endif
     CPUArchState **penv;
     int cpu_index;
 
@@ -290,10 +293,16 @@ void cpu_exec_init(CPUArchState *env)
 #if defined(CONFIG_USER_ONLY)
     cpu_list_unlock();
 #endif
-#if defined(CPU_SAVE_VERSION) && !defined(CONFIG_USER_ONLY)
+#if !defined(CONFIG_USER_ONLY)
     vmstate_register(NULL, cpu_index, &vmstate_cpu_common, env);
+#if defined(CPU_SAVE_VERSION)
     register_savevm(NULL, "cpu", cpu_index, CPU_SAVE_VERSION,
                     cpu_save, cpu_load, env);
+#else
+    if (cc->vmsd != NULL) {
+        vmstate_register(NULL, cpu_index, cc->vmsd, cpu);
+    }
+#endif
 #endif
 }
 

include/qom/cpu.h

@@ -43,6 +43,7 @@ typedef struct CPUState CPUState;
  * @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.
+ * @vmsd: State description for migration.
  *
  * Represents a CPU family or model.
  */
@@ -54,6 +55,8 @@ typedef struct CPUClass {
     ObjectClass *(*class_by_name)(const char *cpu_model);
 
     void (*reset)(CPUState *cpu);
+
+    const struct VMStateDescription *vmsd;
 } CPUClass;
 
 struct KVMState;