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
25 QemuThread thread;
26 QemuMutex init_done_lock;
27 QemuCond init_done_cond; /* is thread initialization done? */
28 bool stopping;
29 };
30
31 static __thread IOThread *my_iothread;
32
qemu_get_current_aio_context(void)33 AioContext *qemu_get_current_aio_context(void)
34 {
35 return my_iothread ? my_iothread->ctx : qemu_get_aio_context();
36 }
37
iothread_run(void * opaque)38 static void *iothread_run(void *opaque)
39 {
40 IOThread *iothread = opaque;
41
42 rcu_register_thread();
43
44 my_iothread = iothread;
45 qemu_mutex_lock(&iothread->init_done_lock);
46 iothread->ctx = aio_context_new(&error_abort);
47 qemu_cond_signal(&iothread->init_done_cond);
48 qemu_mutex_unlock(&iothread->init_done_lock);
49
50 while (!atomic_read(&iothread->stopping)) {
51 aio_poll(iothread->ctx, true);
52 }
53
54 rcu_unregister_thread();
55 return NULL;
56 }
57
iothread_stop_bh(void * opaque)58 static void iothread_stop_bh(void *opaque)
59 {
60 IOThread *iothread = opaque;
61
62 iothread->stopping = true;
63 }
64
iothread_join(IOThread * iothread)65 void iothread_join(IOThread *iothread)
66 {
67 aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread);
68 qemu_thread_join(&iothread->thread);
69 qemu_cond_destroy(&iothread->init_done_cond);
70 qemu_mutex_destroy(&iothread->init_done_lock);
71 aio_context_unref(iothread->ctx);
72 g_free(iothread);
73 }
74
iothread_new(void)75 IOThread *iothread_new(void)
76 {
77 IOThread *iothread = g_new0(IOThread, 1);
78
79 qemu_mutex_init(&iothread->init_done_lock);
80 qemu_cond_init(&iothread->init_done_cond);
81 qemu_thread_create(&iothread->thread, NULL, iothread_run,
82 iothread, QEMU_THREAD_JOINABLE);
83
84 /* Wait for initialization to complete */
85 qemu_mutex_lock(&iothread->init_done_lock);
86 while (iothread->ctx == NULL) {
87 qemu_cond_wait(&iothread->init_done_cond,
88 &iothread->init_done_lock);
89 }
90 qemu_mutex_unlock(&iothread->init_done_lock);
91 return iothread;
92 }
93
iothread_get_aio_context(IOThread * iothread)94 AioContext *iothread_get_aio_context(IOThread *iothread)
95 {
96 return iothread->ctx;
97 }
98