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