[PATCH 13/18] cpu: Implement cpu_thread_is_idle() for qemu-user

[Ilya Leoshkevich <iii@linux.ibm.com>]

Stopped CPUs are parked until cpu_thread_is_idle() is true, so
implement it for qemu-user. Share a part of the qemu-system's
implementation.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 accel/tcg/user-exec.c     | 12 ++++++++++++
 cpu-common.c              | 19 +++++++++++++++++++
 include/exec/cpu-common.h |  3 +++
 include/sysemu/cpus.h     |  1 -
 system/cpus.c             | 17 ++++-------------
 5 files changed, 38 insertions(+), 14 deletions(-)

diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
index 3ebace1e833..57a13c81fc4 100644
--- a/accel/tcg/user-exec.c
+++ b/accel/tcg/user-exec.c
@@ -1317,3 +1317,15 @@ void cpu_exit_syscall(CPUState *cs)
 {
     cs->in_syscall = false;
 }
+
+bool cpu_is_stopped(CPUState *cpu)
+{
+    return cpu->stopped;
+}
+
+bool cpu_thread_is_idle(CPUState *cpu)
+{
+    int ret = cpu_thread_is_idle_common(cpu);
+
+    return ret == -1 ? true : ret;
+}
diff --git a/cpu-common.c b/cpu-common.c
index cb7c10a3915..2822ee9373d 100644
--- a/cpu-common.c
+++ b/cpu-common.c
@@ -497,3 +497,22 @@ void run_on_cpu(CPUState *cpu, run_on_cpu_func func, run_on_cpu_data data)
 {
     do_run_on_cpu(cpu, func, data, &bql);
 }
+
+bool cpu_work_list_empty(CPUState *cpu)
+{
+    return QSIMPLEQ_EMPTY_ATOMIC(&cpu->work_list);
+}
+
+int cpu_thread_is_idle_common(CPUState *cpu)
+{
+    if (cpu->stop || !cpu_work_list_empty(cpu)) {
+        return 0;
+    }
+    if (cpu_is_stopped(cpu)) {
+        return 1;
+    }
+    if (!cpu->halted || cpu_has_work(cpu)) {
+        return 0;
+    }
+    return -1;
+}
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index 32bd3cad83f..d7fc24bc13d 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -231,6 +231,9 @@ int cpu_exec_user(CPUState *cs);
 void cpu_enter_syscall(CPUState *cs);
 void cpu_exit_syscall(CPUState *cs);
 
+int cpu_thread_is_idle_common(CPUState *cpu);
+bool cpu_thread_is_idle(CPUState *cpu);
+
 /**
  * env_archcpu(env)
  * @env: The architecture environment
diff --git a/include/sysemu/cpus.h b/include/sysemu/cpus.h
index b4a566cfe75..bfa3fd45650 100644
--- a/include/sysemu/cpus.h
+++ b/include/sysemu/cpus.h
@@ -21,7 +21,6 @@ void dummy_start_vcpu_thread(CPUState *);
 
 void cpus_kick_thread(CPUState *cpu);
 bool cpu_work_list_empty(CPUState *cpu);
-bool cpu_thread_is_idle(CPUState *cpu);
 bool all_cpu_threads_idle(void);
 bool cpu_can_run(CPUState *cpu);
 void qemu_wait_io_event_common(CPUState *cpu);
diff --git a/system/cpus.c b/system/cpus.c
index fe84b822798..13072be26fa 100644
--- a/system/cpus.c
+++ b/system/cpus.c
@@ -75,21 +75,12 @@ bool cpu_is_stopped(CPUState *cpu)
     return cpu->stopped || !runstate_is_running();
 }
 
-bool cpu_work_list_empty(CPUState *cpu)
-{
-    return QSIMPLEQ_EMPTY_ATOMIC(&cpu->work_list);
-}
-
 bool cpu_thread_is_idle(CPUState *cpu)
 {
-    if (cpu->stop || !cpu_work_list_empty(cpu)) {
-        return false;
-    }
-    if (cpu_is_stopped(cpu)) {
-        return true;
-    }
-    if (!cpu->halted || cpu_has_work(cpu)) {
-        return false;
+    int ret = cpu_thread_is_idle_common(cpu);
+
+    if (ret != -1) {
+        return ret;
     }
     if (cpus_accel->cpu_thread_is_idle) {
         return cpus_accel->cpu_thread_is_idle(cpu);
-- 
2.46.0