Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
[qemu.git] / main-loop.c
1 /*
2 * QEMU System Emulator
3 *
4 * Copyright (c) 2003-2008 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "qemu-common.h"
26 #include "qemu/timer.h"
27 #include "qemu/sockets.h" // struct in_addr needed for libslirp.h
28 #include "sysemu/qtest.h"
29 #include "slirp/libslirp.h"
30 #include "qemu/main-loop.h"
31 #include "block/aio.h"
32
33 #ifndef _WIN32
34
35 #include "qemu/compatfd.h"
36
37 /* If we have signalfd, we mask out the signals we want to handle and then
38 * use signalfd to listen for them. We rely on whatever the current signal
39 * handler is to dispatch the signals when we receive them.
40 */
41 static void sigfd_handler(void *opaque)
42 {
43 int fd = (intptr_t)opaque;
44 struct qemu_signalfd_siginfo info;
45 struct sigaction action;
46 ssize_t len;
47
48 while (1) {
49 do {
50 len = read(fd, &info, sizeof(info));
51 } while (len == -1 && errno == EINTR);
52
53 if (len == -1 && errno == EAGAIN) {
54 break;
55 }
56
57 if (len != sizeof(info)) {
58 printf("read from sigfd returned %zd: %m\n", len);
59 return;
60 }
61
62 sigaction(info.ssi_signo, NULL, &action);
63 if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {
64 action.sa_sigaction(info.ssi_signo,
65 (siginfo_t *)&info, NULL);
66 } else if (action.sa_handler) {
67 action.sa_handler(info.ssi_signo);
68 }
69 }
70 }
71
72 static int qemu_signal_init(void)
73 {
74 int sigfd;
75 sigset_t set;
76
77 /*
78 * SIG_IPI must be blocked in the main thread and must not be caught
79 * by sigwait() in the signal thread. Otherwise, the cpu thread will
80 * not catch it reliably.
81 */
82 sigemptyset(&set);
83 sigaddset(&set, SIG_IPI);
84 sigaddset(&set, SIGIO);
85 sigaddset(&set, SIGALRM);
86 sigaddset(&set, SIGBUS);
87 pthread_sigmask(SIG_BLOCK, &set, NULL);
88
89 sigdelset(&set, SIG_IPI);
90 sigfd = qemu_signalfd(&set);
91 if (sigfd == -1) {
92 fprintf(stderr, "failed to create signalfd\n");
93 return -errno;
94 }
95
96 fcntl_setfl(sigfd, O_NONBLOCK);
97
98 qemu_set_fd_handler2(sigfd, NULL, sigfd_handler, NULL,
99 (void *)(intptr_t)sigfd);
100
101 return 0;
102 }
103
104 #else /* _WIN32 */
105
106 static int qemu_signal_init(void)
107 {
108 return 0;
109 }
110 #endif
111
112 static AioContext *qemu_aio_context;
113
114 AioContext *qemu_get_aio_context(void)
115 {
116 return qemu_aio_context;
117 }
118
119 void qemu_notify_event(void)
120 {
121 if (!qemu_aio_context) {
122 return;
123 }
124 aio_notify(qemu_aio_context);
125 }
126
127 static GArray *gpollfds;
128
129 int qemu_init_main_loop(void)
130 {
131 int ret;
132 GSource *src;
133
134 init_clocks();
135
136 ret = qemu_signal_init();
137 if (ret) {
138 return ret;
139 }
140
141 gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
142 qemu_aio_context = aio_context_new();
143 src = aio_get_g_source(qemu_aio_context);
144 g_source_attach(src, NULL);
145 g_source_unref(src);
146 return 0;
147 }
148
149 static int max_priority;
150
151 #ifndef _WIN32
152 static int glib_pollfds_idx;
153 static int glib_n_poll_fds;
154
155 static void glib_pollfds_fill(int64_t *cur_timeout)
156 {
157 GMainContext *context = g_main_context_default();
158 int timeout = 0;
159 int64_t timeout_ns;
160 int n;
161
162 g_main_context_prepare(context, &max_priority);
163
164 glib_pollfds_idx = gpollfds->len;
165 n = glib_n_poll_fds;
166 do {
167 GPollFD *pfds;
168 glib_n_poll_fds = n;
169 g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds);
170 pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
171 n = g_main_context_query(context, max_priority, &timeout, pfds,
172 glib_n_poll_fds);
173 } while (n != glib_n_poll_fds);
174
175 if (timeout < 0) {
176 timeout_ns = -1;
177 } else {
178 timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS;
179 }
180
181 *cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout);
182 }
183
184 static void glib_pollfds_poll(void)
185 {
186 GMainContext *context = g_main_context_default();
187 GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
188
189 if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
190 g_main_context_dispatch(context);
191 }
192 }
193
194 #define MAX_MAIN_LOOP_SPIN (1000)
195
196 static int os_host_main_loop_wait(int64_t timeout)
197 {
198 int ret;
199 static int spin_counter;
200
201 glib_pollfds_fill(&timeout);
202
203 /* If the I/O thread is very busy or we are incorrectly busy waiting in
204 * the I/O thread, this can lead to starvation of the BQL such that the
205 * VCPU threads never run. To make sure we can detect the later case,
206 * print a message to the screen. If we run into this condition, create
207 * a fake timeout in order to give the VCPU threads a chance to run.
208 */
209 if (!timeout && (spin_counter > MAX_MAIN_LOOP_SPIN)) {
210 static bool notified;
211
212 if (!notified && !qtest_enabled()) {
213 fprintf(stderr,
214 "main-loop: WARNING: I/O thread spun for %d iterations\n",
215 MAX_MAIN_LOOP_SPIN);
216 notified = true;
217 }
218
219 timeout = SCALE_MS;
220 }
221
222 if (timeout) {
223 spin_counter = 0;
224 qemu_mutex_unlock_iothread();
225 } else {
226 spin_counter++;
227 }
228
229 ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout);
230
231 if (timeout) {
232 qemu_mutex_lock_iothread();
233 }
234
235 glib_pollfds_poll();
236 return ret;
237 }
238 #else
239 /***********************************************************/
240 /* Polling handling */
241
242 typedef struct PollingEntry {
243 PollingFunc *func;
244 void *opaque;
245 struct PollingEntry *next;
246 } PollingEntry;
247
248 static PollingEntry *first_polling_entry;
249
250 int qemu_add_polling_cb(PollingFunc *func, void *opaque)
251 {
252 PollingEntry **ppe, *pe;
253 pe = g_malloc0(sizeof(PollingEntry));
254 pe->func = func;
255 pe->opaque = opaque;
256 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);
257 *ppe = pe;
258 return 0;
259 }
260
261 void qemu_del_polling_cb(PollingFunc *func, void *opaque)
262 {
263 PollingEntry **ppe, *pe;
264 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {
265 pe = *ppe;
266 if (pe->func == func && pe->opaque == opaque) {
267 *ppe = pe->next;
268 g_free(pe);
269 break;
270 }
271 }
272 }
273
274 /***********************************************************/
275 /* Wait objects support */
276 typedef struct WaitObjects {
277 int num;
278 int revents[MAXIMUM_WAIT_OBJECTS + 1];
279 HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
280 WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
281 void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
282 } WaitObjects;
283
284 static WaitObjects wait_objects = {0};
285
286 int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
287 {
288 WaitObjects *w = &wait_objects;
289 if (w->num >= MAXIMUM_WAIT_OBJECTS) {
290 return -1;
291 }
292 w->events[w->num] = handle;
293 w->func[w->num] = func;
294 w->opaque[w->num] = opaque;
295 w->revents[w->num] = 0;
296 w->num++;
297 return 0;
298 }
299
300 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
301 {
302 int i, found;
303 WaitObjects *w = &wait_objects;
304
305 found = 0;
306 for (i = 0; i < w->num; i++) {
307 if (w->events[i] == handle) {
308 found = 1;
309 }
310 if (found) {
311 w->events[i] = w->events[i + 1];
312 w->func[i] = w->func[i + 1];
313 w->opaque[i] = w->opaque[i + 1];
314 w->revents[i] = w->revents[i + 1];
315 }
316 }
317 if (found) {
318 w->num--;
319 }
320 }
321
322 void qemu_fd_register(int fd)
323 {
324 WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
325 FD_READ | FD_ACCEPT | FD_CLOSE |
326 FD_CONNECT | FD_WRITE | FD_OOB);
327 }
328
329 static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
330 fd_set *xfds)
331 {
332 int nfds = -1;
333 int i;
334
335 for (i = 0; i < pollfds->len; i++) {
336 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
337 int fd = pfd->fd;
338 int events = pfd->events;
339 if (events & G_IO_IN) {
340 FD_SET(fd, rfds);
341 nfds = MAX(nfds, fd);
342 }
343 if (events & G_IO_OUT) {
344 FD_SET(fd, wfds);
345 nfds = MAX(nfds, fd);
346 }
347 if (events & G_IO_PRI) {
348 FD_SET(fd, xfds);
349 nfds = MAX(nfds, fd);
350 }
351 }
352 return nfds;
353 }
354
355 static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
356 fd_set *wfds, fd_set *xfds)
357 {
358 int i;
359
360 for (i = 0; i < pollfds->len; i++) {
361 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
362 int fd = pfd->fd;
363 int revents = 0;
364
365 if (FD_ISSET(fd, rfds)) {
366 revents |= G_IO_IN;
367 }
368 if (FD_ISSET(fd, wfds)) {
369 revents |= G_IO_OUT;
370 }
371 if (FD_ISSET(fd, xfds)) {
372 revents |= G_IO_PRI;
373 }
374 pfd->revents = revents & pfd->events;
375 }
376 }
377
378 static int os_host_main_loop_wait(int64_t timeout)
379 {
380 GMainContext *context = g_main_context_default();
381 GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
382 int select_ret = 0;
383 int g_poll_ret, ret, i, n_poll_fds;
384 PollingEntry *pe;
385 WaitObjects *w = &wait_objects;
386 gint poll_timeout;
387 int64_t poll_timeout_ns;
388 static struct timeval tv0;
389 fd_set rfds, wfds, xfds;
390 int nfds;
391
392 /* XXX: need to suppress polling by better using win32 events */
393 ret = 0;
394 for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
395 ret |= pe->func(pe->opaque);
396 }
397 if (ret != 0) {
398 return ret;
399 }
400
401 FD_ZERO(&rfds);
402 FD_ZERO(&wfds);
403 FD_ZERO(&xfds);
404 nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
405 if (nfds >= 0) {
406 select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
407 if (select_ret != 0) {
408 timeout = 0;
409 }
410 if (select_ret > 0) {
411 pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
412 }
413 }
414
415 g_main_context_prepare(context, &max_priority);
416 n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
417 poll_fds, ARRAY_SIZE(poll_fds));
418 g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));
419
420 for (i = 0; i < w->num; i++) {
421 poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i];
422 poll_fds[n_poll_fds + i].events = G_IO_IN;
423 }
424
425 if (poll_timeout < 0) {
426 poll_timeout_ns = -1;
427 } else {
428 poll_timeout_ns = (int64_t)poll_timeout * (int64_t)SCALE_MS;
429 }
430
431 poll_timeout_ns = qemu_soonest_timeout(poll_timeout_ns, timeout);
432
433 qemu_mutex_unlock_iothread();
434 g_poll_ret = qemu_poll_ns(poll_fds, n_poll_fds + w->num, poll_timeout_ns);
435
436 qemu_mutex_lock_iothread();
437 if (g_poll_ret > 0) {
438 for (i = 0; i < w->num; i++) {
439 w->revents[i] = poll_fds[n_poll_fds + i].revents;
440 }
441 for (i = 0; i < w->num; i++) {
442 if (w->revents[i] && w->func[i]) {
443 w->func[i](w->opaque[i]);
444 }
445 }
446 }
447
448 if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
449 g_main_context_dispatch(context);
450 }
451
452 return select_ret || g_poll_ret;
453 }
454 #endif
455
456 int main_loop_wait(int nonblocking)
457 {
458 int ret;
459 uint32_t timeout = UINT32_MAX;
460 int64_t timeout_ns;
461
462 if (nonblocking) {
463 timeout = 0;
464 }
465
466 /* poll any events */
467 g_array_set_size(gpollfds, 0); /* reset for new iteration */
468 /* XXX: separate device handlers from system ones */
469 #ifdef CONFIG_SLIRP
470 slirp_pollfds_fill(gpollfds, &timeout);
471 #endif
472 qemu_iohandler_fill(gpollfds);
473
474 if (timeout == UINT32_MAX) {
475 timeout_ns = -1;
476 } else {
477 timeout_ns = (uint64_t)timeout * (int64_t)(SCALE_MS);
478 }
479
480 timeout_ns = qemu_soonest_timeout(timeout_ns,
481 timerlistgroup_deadline_ns(
482 &main_loop_tlg));
483
484 ret = os_host_main_loop_wait(timeout_ns);
485 qemu_iohandler_poll(gpollfds, ret);
486 #ifdef CONFIG_SLIRP
487 slirp_pollfds_poll(gpollfds, (ret < 0));
488 #endif
489
490 qemu_clock_run_all_timers();
491
492 return ret;
493 }
494
495 /* Functions to operate on the main QEMU AioContext. */
496
497 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
498 {
499 return aio_bh_new(qemu_aio_context, cb, opaque);
500 }
501
502 bool qemu_aio_wait(void)
503 {
504 return aio_poll(qemu_aio_context, true);
505 }
506
507 #ifdef CONFIG_POSIX
508 void qemu_aio_set_fd_handler(int fd,
509 IOHandler *io_read,
510 IOHandler *io_write,
511 void *opaque)
512 {
513 aio_set_fd_handler(qemu_aio_context, fd, io_read, io_write, opaque);
514 }
515 #endif
516
517 void qemu_aio_set_event_notifier(EventNotifier *notifier,
518 EventNotifierHandler *io_read)
519 {
520 aio_set_event_notifier(qemu_aio_context, notifier, io_read);
521 }