Merge remote-tracking branch 'remotes/gkurz-gitlab/tags/9p-next-2021-01-15' into...
[qemu.git] / tests / iothread.c
1 /*
2 * Event loop thread implementation for unit tests
3 *
4 * Copyright Red Hat Inc., 2013, 2016
5 *
6 * Authors:
7 * Stefan Hajnoczi <stefanha@redhat.com>
8 * Paolo Bonzini <pbonzini@redhat.com>
9 *
10 * This work is licensed under the terms of the GNU GPL, version 2 or later.
11 * See the COPYING file in the top-level directory.
12 *
13 */
14
15 #include "qemu/osdep.h"
16 #include "qapi/error.h"
17 #include "block/aio.h"
18 #include "qemu/main-loop.h"
19 #include "qemu/rcu.h"
20 #include "iothread.h"
21
22 struct IOThread {
23 AioContext *ctx;
24 GMainContext *worker_context;
25 GMainLoop *main_loop;
26
27 QemuThread thread;
28 QemuMutex init_done_lock;
29 QemuCond init_done_cond; /* is thread initialization done? */
30 bool stopping;
31 };
32
33 static __thread IOThread *my_iothread;
34
35 AioContext *qemu_get_current_aio_context(void)
36 {
37 return my_iothread ? my_iothread->ctx : qemu_get_aio_context();
38 }
39
40 static void iothread_init_gcontext(IOThread *iothread)
41 {
42 GSource *source;
43
44 iothread->worker_context = g_main_context_new();
45 source = aio_get_g_source(iothread_get_aio_context(iothread));
46 g_source_attach(source, iothread->worker_context);
47 g_source_unref(source);
48 iothread->main_loop = g_main_loop_new(iothread->worker_context, TRUE);
49 }
50
51 static void *iothread_run(void *opaque)
52 {
53 IOThread *iothread = opaque;
54
55 rcu_register_thread();
56
57 my_iothread = iothread;
58 qemu_mutex_lock(&iothread->init_done_lock);
59 iothread->ctx = aio_context_new(&error_abort);
60
61 /*
62 * We must connect the ctx to a GMainContext, because in older versions
63 * of glib the g_source_ref()/unref() functions are not threadsafe
64 * on sources without a context.
65 */
66 iothread_init_gcontext(iothread);
67
68 /*
69 * g_main_context_push_thread_default() must be called before anything
70 * in this new thread uses glib.
71 */
72 g_main_context_push_thread_default(iothread->worker_context);
73
74 qemu_cond_signal(&iothread->init_done_cond);
75 qemu_mutex_unlock(&iothread->init_done_lock);
76
77 while (!qatomic_read(&iothread->stopping)) {
78 aio_poll(iothread->ctx, true);
79 }
80
81 g_main_context_pop_thread_default(iothread->worker_context);
82 rcu_unregister_thread();
83 return NULL;
84 }
85
86 static void iothread_stop_bh(void *opaque)
87 {
88 IOThread *iothread = opaque;
89
90 iothread->stopping = true;
91 }
92
93 void iothread_join(IOThread *iothread)
94 {
95 aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread);
96 qemu_thread_join(&iothread->thread);
97 g_main_context_unref(iothread->worker_context);
98 g_main_loop_unref(iothread->main_loop);
99 qemu_cond_destroy(&iothread->init_done_cond);
100 qemu_mutex_destroy(&iothread->init_done_lock);
101 aio_context_unref(iothread->ctx);
102 g_free(iothread);
103 }
104
105 IOThread *iothread_new(void)
106 {
107 IOThread *iothread = g_new0(IOThread, 1);
108
109 qemu_mutex_init(&iothread->init_done_lock);
110 qemu_cond_init(&iothread->init_done_cond);
111 qemu_thread_create(&iothread->thread, NULL, iothread_run,
112 iothread, QEMU_THREAD_JOINABLE);
113
114 /* Wait for initialization to complete */
115 qemu_mutex_lock(&iothread->init_done_lock);
116 while (iothread->ctx == NULL) {
117 qemu_cond_wait(&iothread->init_done_cond,
118 &iothread->init_done_lock);
119 }
120 qemu_mutex_unlock(&iothread->init_done_lock);
121 return iothread;
122 }
123
124 AioContext *iothread_get_aio_context(IOThread *iothread)
125 {
126 return iothread->ctx;
127 }