ssi: Convert legacy SSI_SLAVE -> DEVICE casts
[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 "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 }