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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/osdep.h" | |
26 | #include "qemu-common.h" | |
27 | #include "qemu/timer.h" | |
28 | #include "qemu/sockets.h" // struct in_addr needed for libslirp.h | |
29 | #include "sysemu/qtest.h" | |
30 | #include "slirp/libslirp.h" | |
31 | #include "qemu/main-loop.h" | |
32 | #include "block/aio.h" | |
33 | ||
34 | #ifndef _WIN32 | |
35 | ||
36 | #include "qemu/compatfd.h" | |
37 | ||
38 | /* If we have signalfd, we mask out the signals we want to handle and then | |
39 | * use signalfd to listen for them. We rely on whatever the current signal | |
40 | * handler is to dispatch the signals when we receive them. | |
41 | */ | |
42 | static void sigfd_handler(void *opaque) | |
43 | { | |
44 | int fd = (intptr_t)opaque; | |
45 | struct qemu_signalfd_siginfo info; | |
46 | struct sigaction action; | |
47 | ssize_t len; | |
48 | ||
49 | while (1) { | |
50 | do { | |
51 | len = read(fd, &info, sizeof(info)); | |
52 | } while (len == -1 && errno == EINTR); | |
53 | ||
54 | if (len == -1 && errno == EAGAIN) { | |
55 | break; | |
56 | } | |
57 | ||
58 | if (len != sizeof(info)) { | |
59 | printf("read from sigfd returned %zd: %m\n", len); | |
60 | return; | |
61 | } | |
62 | ||
63 | sigaction(info.ssi_signo, NULL, &action); | |
64 | if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) { | |
65 | action.sa_sigaction(info.ssi_signo, | |
66 | (siginfo_t *)&info, NULL); | |
67 | } else if (action.sa_handler) { | |
68 | action.sa_handler(info.ssi_signo); | |
69 | } | |
70 | } | |
71 | } | |
72 | ||
73 | static int qemu_signal_init(void) | |
74 | { | |
75 | int sigfd; | |
76 | sigset_t set; | |
77 | ||
78 | /* | |
79 | * SIG_IPI must be blocked in the main thread and must not be caught | |
80 | * by sigwait() in the signal thread. Otherwise, the cpu thread will | |
81 | * not catch it reliably. | |
82 | */ | |
83 | sigemptyset(&set); | |
84 | sigaddset(&set, SIG_IPI); | |
85 | sigaddset(&set, SIGIO); | |
86 | sigaddset(&set, SIGALRM); | |
87 | sigaddset(&set, SIGBUS); | |
88 | /* SIGINT cannot be handled via signalfd, so that ^C can be used | |
89 | * to interrupt QEMU when it is being run under gdb. SIGHUP and | |
90 | * SIGTERM are also handled asynchronously, even though it is not | |
91 | * strictly necessary, because they use the same handler as SIGINT. | |
92 | */ | |
93 | pthread_sigmask(SIG_BLOCK, &set, NULL); | |
94 | ||
95 | sigdelset(&set, SIG_IPI); | |
96 | sigfd = qemu_signalfd(&set); | |
97 | if (sigfd == -1) { | |
98 | fprintf(stderr, "failed to create signalfd\n"); | |
99 | return -errno; | |
100 | } | |
101 | ||
102 | fcntl_setfl(sigfd, O_NONBLOCK); | |
103 | ||
104 | qemu_set_fd_handler(sigfd, sigfd_handler, NULL, (void *)(intptr_t)sigfd); | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | #else /* _WIN32 */ | |
110 | ||
111 | static int qemu_signal_init(void) | |
112 | { | |
113 | return 0; | |
114 | } | |
115 | #endif | |
116 | ||
117 | static AioContext *qemu_aio_context; | |
118 | static QEMUBH *qemu_notify_bh; | |
119 | ||
120 | static void notify_event_cb(void *opaque) | |
121 | { | |
122 | /* No need to do anything; this bottom half is only used to | |
123 | * kick the kernel out of ppoll/poll/WaitForMultipleObjects. | |
124 | */ | |
125 | } | |
126 | ||
127 | AioContext *qemu_get_aio_context(void) | |
128 | { | |
129 | return qemu_aio_context; | |
130 | } | |
131 | ||
132 | void qemu_notify_event(void) | |
133 | { | |
134 | if (!qemu_aio_context) { | |
135 | return; | |
136 | } | |
137 | qemu_bh_schedule(qemu_notify_bh); | |
138 | } | |
139 | ||
140 | static GArray *gpollfds; | |
141 | ||
142 | int qemu_init_main_loop(Error **errp) | |
143 | { | |
144 | int ret; | |
145 | GSource *src; | |
146 | Error *local_error = NULL; | |
147 | ||
148 | init_clocks(); | |
149 | ||
150 | ret = qemu_signal_init(); | |
151 | if (ret) { | |
152 | return ret; | |
153 | } | |
154 | ||
155 | qemu_aio_context = aio_context_new(&local_error); | |
156 | qemu_notify_bh = qemu_bh_new(notify_event_cb, NULL); | |
157 | if (!qemu_aio_context) { | |
158 | error_propagate(errp, local_error); | |
159 | return -EMFILE; | |
160 | } | |
161 | gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD)); | |
162 | src = aio_get_g_source(qemu_aio_context); | |
163 | g_source_attach(src, NULL); | |
164 | g_source_unref(src); | |
165 | src = iohandler_get_g_source(); | |
166 | g_source_attach(src, NULL); | |
167 | g_source_unref(src); | |
168 | return 0; | |
169 | } | |
170 | ||
171 | static int max_priority; | |
172 | ||
173 | #ifndef _WIN32 | |
174 | static int glib_pollfds_idx; | |
175 | static int glib_n_poll_fds; | |
176 | ||
177 | static void glib_pollfds_fill(int64_t *cur_timeout) | |
178 | { | |
179 | GMainContext *context = g_main_context_default(); | |
180 | int timeout = 0; | |
181 | int64_t timeout_ns; | |
182 | int n; | |
183 | ||
184 | g_main_context_prepare(context, &max_priority); | |
185 | ||
186 | glib_pollfds_idx = gpollfds->len; | |
187 | n = glib_n_poll_fds; | |
188 | do { | |
189 | GPollFD *pfds; | |
190 | glib_n_poll_fds = n; | |
191 | g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds); | |
192 | pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx); | |
193 | n = g_main_context_query(context, max_priority, &timeout, pfds, | |
194 | glib_n_poll_fds); | |
195 | } while (n != glib_n_poll_fds); | |
196 | ||
197 | if (timeout < 0) { | |
198 | timeout_ns = -1; | |
199 | } else { | |
200 | timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS; | |
201 | } | |
202 | ||
203 | *cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout); | |
204 | } | |
205 | ||
206 | static void glib_pollfds_poll(void) | |
207 | { | |
208 | GMainContext *context = g_main_context_default(); | |
209 | GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx); | |
210 | ||
211 | if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) { | |
212 | g_main_context_dispatch(context); | |
213 | } | |
214 | } | |
215 | ||
216 | #define MAX_MAIN_LOOP_SPIN (1000) | |
217 | ||
218 | static int os_host_main_loop_wait(int64_t timeout) | |
219 | { | |
220 | int ret; | |
221 | static int spin_counter; | |
222 | ||
223 | glib_pollfds_fill(&timeout); | |
224 | ||
225 | /* If the I/O thread is very busy or we are incorrectly busy waiting in | |
226 | * the I/O thread, this can lead to starvation of the BQL such that the | |
227 | * VCPU threads never run. To make sure we can detect the later case, | |
228 | * print a message to the screen. If we run into this condition, create | |
229 | * a fake timeout in order to give the VCPU threads a chance to run. | |
230 | */ | |
231 | if (!timeout && (spin_counter > MAX_MAIN_LOOP_SPIN)) { | |
232 | static bool notified; | |
233 | ||
234 | if (!notified && !qtest_driver()) { | |
235 | fprintf(stderr, | |
236 | "main-loop: WARNING: I/O thread spun for %d iterations\n", | |
237 | MAX_MAIN_LOOP_SPIN); | |
238 | notified = true; | |
239 | } | |
240 | ||
241 | timeout = SCALE_MS; | |
242 | } | |
243 | ||
244 | if (timeout) { | |
245 | spin_counter = 0; | |
246 | qemu_mutex_unlock_iothread(); | |
247 | } else { | |
248 | spin_counter++; | |
249 | } | |
250 | ||
251 | ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout); | |
252 | ||
253 | if (timeout) { | |
254 | qemu_mutex_lock_iothread(); | |
255 | } | |
256 | ||
257 | glib_pollfds_poll(); | |
258 | return ret; | |
259 | } | |
260 | #else | |
261 | /***********************************************************/ | |
262 | /* Polling handling */ | |
263 | ||
264 | typedef struct PollingEntry { | |
265 | PollingFunc *func; | |
266 | void *opaque; | |
267 | struct PollingEntry *next; | |
268 | } PollingEntry; | |
269 | ||
270 | static PollingEntry *first_polling_entry; | |
271 | ||
272 | int qemu_add_polling_cb(PollingFunc *func, void *opaque) | |
273 | { | |
274 | PollingEntry **ppe, *pe; | |
275 | pe = g_malloc0(sizeof(PollingEntry)); | |
276 | pe->func = func; | |
277 | pe->opaque = opaque; | |
278 | for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next); | |
279 | *ppe = pe; | |
280 | return 0; | |
281 | } | |
282 | ||
283 | void qemu_del_polling_cb(PollingFunc *func, void *opaque) | |
284 | { | |
285 | PollingEntry **ppe, *pe; | |
286 | for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) { | |
287 | pe = *ppe; | |
288 | if (pe->func == func && pe->opaque == opaque) { | |
289 | *ppe = pe->next; | |
290 | g_free(pe); | |
291 | break; | |
292 | } | |
293 | } | |
294 | } | |
295 | ||
296 | /***********************************************************/ | |
297 | /* Wait objects support */ | |
298 | typedef struct WaitObjects { | |
299 | int num; | |
300 | int revents[MAXIMUM_WAIT_OBJECTS + 1]; | |
301 | HANDLE events[MAXIMUM_WAIT_OBJECTS + 1]; | |
302 | WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1]; | |
303 | void *opaque[MAXIMUM_WAIT_OBJECTS + 1]; | |
304 | } WaitObjects; | |
305 | ||
306 | static WaitObjects wait_objects = {0}; | |
307 | ||
308 | int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque) | |
309 | { | |
310 | WaitObjects *w = &wait_objects; | |
311 | if (w->num >= MAXIMUM_WAIT_OBJECTS) { | |
312 | return -1; | |
313 | } | |
314 | w->events[w->num] = handle; | |
315 | w->func[w->num] = func; | |
316 | w->opaque[w->num] = opaque; | |
317 | w->revents[w->num] = 0; | |
318 | w->num++; | |
319 | return 0; | |
320 | } | |
321 | ||
322 | void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque) | |
323 | { | |
324 | int i, found; | |
325 | WaitObjects *w = &wait_objects; | |
326 | ||
327 | found = 0; | |
328 | for (i = 0; i < w->num; i++) { | |
329 | if (w->events[i] == handle) { | |
330 | found = 1; | |
331 | } | |
332 | if (found) { | |
333 | w->events[i] = w->events[i + 1]; | |
334 | w->func[i] = w->func[i + 1]; | |
335 | w->opaque[i] = w->opaque[i + 1]; | |
336 | w->revents[i] = w->revents[i + 1]; | |
337 | } | |
338 | } | |
339 | if (found) { | |
340 | w->num--; | |
341 | } | |
342 | } | |
343 | ||
344 | void qemu_fd_register(int fd) | |
345 | { | |
346 | WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier), | |
347 | FD_READ | FD_ACCEPT | FD_CLOSE | | |
348 | FD_CONNECT | FD_WRITE | FD_OOB); | |
349 | } | |
350 | ||
351 | static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds, | |
352 | fd_set *xfds) | |
353 | { | |
354 | int nfds = -1; | |
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 events = pfd->events; | |
361 | if (events & G_IO_IN) { | |
362 | FD_SET(fd, rfds); | |
363 | nfds = MAX(nfds, fd); | |
364 | } | |
365 | if (events & G_IO_OUT) { | |
366 | FD_SET(fd, wfds); | |
367 | nfds = MAX(nfds, fd); | |
368 | } | |
369 | if (events & G_IO_PRI) { | |
370 | FD_SET(fd, xfds); | |
371 | nfds = MAX(nfds, fd); | |
372 | } | |
373 | } | |
374 | return nfds; | |
375 | } | |
376 | ||
377 | static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds, | |
378 | fd_set *wfds, fd_set *xfds) | |
379 | { | |
380 | int i; | |
381 | ||
382 | for (i = 0; i < pollfds->len; i++) { | |
383 | GPollFD *pfd = &g_array_index(pollfds, GPollFD, i); | |
384 | int fd = pfd->fd; | |
385 | int revents = 0; | |
386 | ||
387 | if (FD_ISSET(fd, rfds)) { | |
388 | revents |= G_IO_IN; | |
389 | } | |
390 | if (FD_ISSET(fd, wfds)) { | |
391 | revents |= G_IO_OUT; | |
392 | } | |
393 | if (FD_ISSET(fd, xfds)) { | |
394 | revents |= G_IO_PRI; | |
395 | } | |
396 | pfd->revents = revents & pfd->events; | |
397 | } | |
398 | } | |
399 | ||
400 | static int os_host_main_loop_wait(int64_t timeout) | |
401 | { | |
402 | GMainContext *context = g_main_context_default(); | |
403 | GPollFD poll_fds[1024 * 2]; /* this is probably overkill */ | |
404 | int select_ret = 0; | |
405 | int g_poll_ret, ret, i, n_poll_fds; | |
406 | PollingEntry *pe; | |
407 | WaitObjects *w = &wait_objects; | |
408 | gint poll_timeout; | |
409 | int64_t poll_timeout_ns; | |
410 | static struct timeval tv0; | |
411 | fd_set rfds, wfds, xfds; | |
412 | int nfds; | |
413 | ||
414 | /* XXX: need to suppress polling by better using win32 events */ | |
415 | ret = 0; | |
416 | for (pe = first_polling_entry; pe != NULL; pe = pe->next) { | |
417 | ret |= pe->func(pe->opaque); | |
418 | } | |
419 | if (ret != 0) { | |
420 | return ret; | |
421 | } | |
422 | ||
423 | FD_ZERO(&rfds); | |
424 | FD_ZERO(&wfds); | |
425 | FD_ZERO(&xfds); | |
426 | nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds); | |
427 | if (nfds >= 0) { | |
428 | select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0); | |
429 | if (select_ret != 0) { | |
430 | timeout = 0; | |
431 | } | |
432 | if (select_ret > 0) { | |
433 | pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds); | |
434 | } | |
435 | } | |
436 | ||
437 | g_main_context_prepare(context, &max_priority); | |
438 | n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout, | |
439 | poll_fds, ARRAY_SIZE(poll_fds)); | |
440 | g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds)); | |
441 | ||
442 | for (i = 0; i < w->num; i++) { | |
443 | poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i]; | |
444 | poll_fds[n_poll_fds + i].events = G_IO_IN; | |
445 | } | |
446 | ||
447 | if (poll_timeout < 0) { | |
448 | poll_timeout_ns = -1; | |
449 | } else { | |
450 | poll_timeout_ns = (int64_t)poll_timeout * (int64_t)SCALE_MS; | |
451 | } | |
452 | ||
453 | poll_timeout_ns = qemu_soonest_timeout(poll_timeout_ns, timeout); | |
454 | ||
455 | qemu_mutex_unlock_iothread(); | |
456 | g_poll_ret = qemu_poll_ns(poll_fds, n_poll_fds + w->num, poll_timeout_ns); | |
457 | ||
458 | qemu_mutex_lock_iothread(); | |
459 | if (g_poll_ret > 0) { | |
460 | for (i = 0; i < w->num; i++) { | |
461 | w->revents[i] = poll_fds[n_poll_fds + i].revents; | |
462 | } | |
463 | for (i = 0; i < w->num; i++) { | |
464 | if (w->revents[i] && w->func[i]) { | |
465 | w->func[i](w->opaque[i]); | |
466 | } | |
467 | } | |
468 | } | |
469 | ||
470 | if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) { | |
471 | g_main_context_dispatch(context); | |
472 | } | |
473 | ||
474 | return select_ret || g_poll_ret; | |
475 | } | |
476 | #endif | |
477 | ||
478 | int main_loop_wait(int nonblocking) | |
479 | { | |
480 | int ret; | |
481 | uint32_t timeout = UINT32_MAX; | |
482 | int64_t timeout_ns; | |
483 | ||
484 | if (nonblocking) { | |
485 | timeout = 0; | |
486 | } | |
487 | ||
488 | /* poll any events */ | |
489 | g_array_set_size(gpollfds, 0); /* reset for new iteration */ | |
490 | /* XXX: separate device handlers from system ones */ | |
491 | #ifdef CONFIG_SLIRP | |
492 | slirp_pollfds_fill(gpollfds, &timeout); | |
493 | #endif | |
494 | ||
495 | if (timeout == UINT32_MAX) { | |
496 | timeout_ns = -1; | |
497 | } else { | |
498 | timeout_ns = (uint64_t)timeout * (int64_t)(SCALE_MS); | |
499 | } | |
500 | ||
501 | timeout_ns = qemu_soonest_timeout(timeout_ns, | |
502 | timerlistgroup_deadline_ns( | |
503 | &main_loop_tlg)); | |
504 | ||
505 | ret = os_host_main_loop_wait(timeout_ns); | |
506 | #ifdef CONFIG_SLIRP | |
507 | slirp_pollfds_poll(gpollfds, (ret < 0)); | |
508 | #endif | |
509 | ||
510 | /* CPU thread can infinitely wait for event after | |
511 | missing the warp */ | |
512 | qemu_clock_warp(QEMU_CLOCK_VIRTUAL); | |
513 | qemu_clock_run_all_timers(); | |
514 | ||
515 | return ret; | |
516 | } | |
517 | ||
518 | /* Functions to operate on the main QEMU AioContext. */ | |
519 | ||
520 | QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque) | |
521 | { | |
522 | return aio_bh_new(qemu_aio_context, cb, opaque); | |
523 | } |