cpu: cpu_by_arch_id() helper

The helper can be used for CPU object lookup using the CPU's
arch-specific ID (the one returned by CPUClass::get_arch_id()).

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
[Yi Wang: Added documentation comments]
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Yun Liu <liu.yunh@zte.com.cn>
[ehabkost: extracted cpu_by_arch_id() to a separate patch]
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

2 files changed, 18 insertions, 3 deletions

diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 25eefea7ab..b7ac9491c8 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -755,6 +755,16 @@ CPUState *qemu_get_cpu(int index);
 bool cpu_exists(int64_t id);
 
 /**
+ * cpu_by_arch_id:
+ * @id: Guest-exposed CPU ID of the CPU to obtain.
+ *
+ * Get a CPU with matching @id.
+ *
+ * Returns: The CPU or %NULL if there is no matching CPU.
+ */
+CPUState *cpu_by_arch_id(int64_t id);
+
+/**
  * cpu_throttle_set:
  * @new_throttle_pct: Percent of sleep time. Valid range is 1 to 99.
  *
diff --git a/qom/cpu.c b/qom/cpu.c
index 4f38db0dac..e6210d5949 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -34,7 +34,7 @@
 
 CPUInterruptHandler cpu_interrupt_handler;
 
-bool cpu_exists(int64_t id)
+CPUState *cpu_by_arch_id(int64_t id)
 {
     CPUState *cpu;
 
@@ -42,10 +42,15 @@ bool cpu_exists(int64_t id)
         CPUClass *cc = CPU_GET_CLASS(cpu);
 
         if (cc->get_arch_id(cpu) == id) {
-            return true;
+            return cpu;
         }
     }
-    return false;
+    return NULL;
+}
+
+bool cpu_exists(int64_t id)
+{
+    return !!cpu_by_arch_id(id);
 }
 
 CPUState *cpu_generic_init(const char *typename, const char *cpu_model)