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