[Qemu-devel] [PATCH 10/12] cpus-common: Introduce async_safe_run_on_cpu()

[Paolo Bonzini <pbonzini@redhat.com>]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 cpus-common.c     | 25 +++++++++++++++++++++++++
 include/qom/cpu.h | 12 ++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/cpus-common.c b/cpus-common.c
index 59c8dc8..88cf5ec 100644
--- a/cpus-common.c
+++ b/cpus-common.c
@@ -144,6 +144,11 @@ void async_run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data)
     queue_work_on_cpu(cpu, wi);
 }
 
+typedef struct SafeWorkItem {
+    run_on_cpu_func func;
+    void *data;
+} SafeWorkItem;
+
 /* Wait for pending exclusive operations to complete.  The exclusive lock
    must be held.  */
 static inline void exclusive_idle(void)
@@ -208,6 +213,26 @@ void cpu_exec_end(CPUState *cpu)
     qemu_mutex_unlock(&qemu_cpu_list_mutex);
 }
 
+static void async_safe_run_on_cpu_fn(CPUState *cpu, void *data)
+{
+    SafeWorkItem *w = data;
+
+    start_exclusive();
+    w->func(cpu, w->data);
+    end_exclusive();
+    g_free(w);
+}
+
+void async_safe_run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data)
+{
+    SafeWorkItem *w = g_new(SafeWorkItem, 1);
+
+    w->func = func;
+    w->data = data;
+
+    async_run_on_cpu(cpu, async_safe_run_on_cpu_fn, w);
+}
+
 void process_queued_cpu_work(CPUState *cpu)
 {
     struct qemu_work_item *wi;
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 0e04e8f..54a875e 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -663,6 +663,18 @@ void run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data);
 void async_run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data);
 
 /**
+ * async_safe_run_on_cpu:
+ * @cpu: The vCPU to run on.
+ * @func: The function to be executed.
+ * @data: Data to pass to the function.
+ *
+ * Schedules the function @func for execution on the vCPU @cpu asynchronously,
+ * while all other vCPUs are sleeping.  @func is called with the CPU list lock
+ * taken (and for system emulation the BQL); any other lock can be taken safely.
+ */
+void async_safe_run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data);
+
+/**
  * qemu_get_cpu:
  * @index: The CPUState@cpu_index value of the CPU to obtain.
  *
-- 
2.7.4