From 382022929e97e5c5eeebea9e3bab9105e59f1bed Mon Sep 17 00:00:00 2001
From: Eduardo Habkost <ehabkost@redhat.com>
Date: Sun, 4 Mar 2018 12:16:29 -0500
Subject: [PATCH] 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()).

Backports commit 5ce46cb34eecec0bc94a4b1394763f9a1bbe20c3 from qemu
---
 qemu/include/qom/cpu.h | 10 ++++++++++
 qemu/qom/cpu.c         | 11 ++++++++---
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/qemu/include/qom/cpu.h b/qemu/include/qom/cpu.h
index fc19efc2..a5520898 100644
--- a/qemu/include/qom/cpu.h
+++ b/qemu/include/qom/cpu.h
@@ -606,6 +606,16 @@ CPUState *qemu_get_cpu(struct uc_struct *uc, int index);
  */
 bool cpu_exists(struct uc_struct* uc, 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(struct uc_struct *uc, int64_t id);
+
 #ifndef CONFIG_USER_ONLY
 
 typedef void (*CPUInterruptHandler)(CPUState *, int);
diff --git a/qemu/qom/cpu.c b/qemu/qom/cpu.c
index 265be07c..585df6cb 100644
--- a/qemu/qom/cpu.c
+++ b/qemu/qom/cpu.c
@@ -24,15 +24,20 @@
 #include "qemu/log.h"
 #include "uc_priv.h"
 
-bool cpu_exists(struct uc_struct* uc, int64_t id)
+CPUState *cpu_by_arch_id(struct uc_struct *uc, int64_t id)
 {
     CPUState *cpu = uc->cpu;
     CPUClass *cc = CPU_GET_CLASS(uc, cpu);
 
     if (cc->get_arch_id(cpu) == id) {
-        return true;
+        return cpu;
     }
-    return false;
+    return NULL;
+}
+
+bool cpu_exists(struct uc_struct *uc, int64_t id)
+{
+    return !!cpu_by_arch_id(uc, id);
 }
 
 CPUState *cpu_generic_init(struct uc_struct *uc, const char *typename, const char *cpu_model)