qom: Correct object_property_get_int() description
[qemu/ar7.git] / main-loop.c
blob19beae76ad1ab533febfac85d79bd46b9ec38a42
1 /*
2 * QEMU System Emulator
4 * Copyright (c) 2003-2008 Fabrice Bellard
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:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
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.
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"
34 #ifndef _WIN32
36 #include "qemu/compatfd.h"
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.
42 static void sigfd_handler(void *opaque)
44 int fd = (intptr_t)opaque;
45 struct qemu_signalfd_siginfo info;
46 struct sigaction action;
47 ssize_t len;
49 while (1) {
50 do {
51 len = read(fd, &info, sizeof(info));
52 } while (len == -1 && errno == EINTR);
54 if (len == -1 && errno == EAGAIN) {
55 break;
58 if (len != sizeof(info)) {
59 printf("read from sigfd returned %zd: %m\n", len);
60 return;
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);
73 static int qemu_signal_init(void)
75 int sigfd;
76 sigset_t set;
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.
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.
93 pthread_sigmask(SIG_BLOCK, &set, NULL);
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;
102 fcntl_setfl(sigfd, O_NONBLOCK);
104 qemu_set_fd_handler(sigfd, sigfd_handler, NULL, (void *)(intptr_t)sigfd);
106 return 0;
109 #else /* _WIN32 */
111 static int qemu_signal_init(void)
113 return 0;
115 #endif
117 static AioContext *qemu_aio_context;
118 static QEMUBH *qemu_notify_bh;
120 static void notify_event_cb(void *opaque)
122 /* No need to do anything; this bottom half is only used to
123 * kick the kernel out of ppoll/poll/WaitForMultipleObjects.
127 AioContext *qemu_get_aio_context(void)
129 return qemu_aio_context;
132 void qemu_notify_event(void)
134 if (!qemu_aio_context) {
135 return;
137 qemu_bh_schedule(qemu_notify_bh);
140 static GArray *gpollfds;
142 int qemu_init_main_loop(Error **errp)
144 int ret;
145 GSource *src;
146 Error *local_error = NULL;
148 init_clocks();
150 ret = qemu_signal_init();
151 if (ret) {
152 return ret;
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;
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;
171 static int max_priority;
173 #ifndef _WIN32
174 static int glib_pollfds_idx;
175 static int glib_n_poll_fds;
177 static void glib_pollfds_fill(int64_t *cur_timeout)
179 GMainContext *context = g_main_context_default();
180 int timeout = 0;
181 int64_t timeout_ns;
182 int n;
184 g_main_context_prepare(context, &max_priority);
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);
197 if (timeout < 0) {
198 timeout_ns = -1;
199 } else {
200 timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS;
203 *cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout);
206 static void glib_pollfds_poll(void)
208 GMainContext *context = g_main_context_default();
209 GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
211 if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
212 g_main_context_dispatch(context);
216 #define MAX_MAIN_LOOP_SPIN (1000)
218 static int os_host_main_loop_wait(int64_t timeout)
220 int ret;
221 static int spin_counter;
223 glib_pollfds_fill(&timeout);
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.
231 if (!timeout && (spin_counter > MAX_MAIN_LOOP_SPIN)) {
232 static bool notified;
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;
241 timeout = SCALE_MS;
244 if (timeout) {
245 spin_counter = 0;
246 qemu_mutex_unlock_iothread();
247 } else {
248 spin_counter++;
251 ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout);
253 if (timeout) {
254 qemu_mutex_lock_iothread();
257 glib_pollfds_poll();
258 return ret;
260 #else
261 /***********************************************************/
262 /* Polling handling */
264 typedef struct PollingEntry {
265 PollingFunc *func;
266 void *opaque;
267 struct PollingEntry *next;
268 } PollingEntry;
270 static PollingEntry *first_polling_entry;
272 int qemu_add_polling_cb(PollingFunc *func, void *opaque)
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;
283 void qemu_del_polling_cb(PollingFunc *func, void *opaque)
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;
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;
306 static WaitObjects wait_objects = {0};
308 int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
310 WaitObjects *w = &wait_objects;
311 if (w->num >= MAXIMUM_WAIT_OBJECTS) {
312 return -1;
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;
322 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
324 int i, found;
325 WaitObjects *w = &wait_objects;
327 found = 0;
328 for (i = 0; i < w->num; i++) {
329 if (w->events[i] == handle) {
330 found = 1;
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];
339 if (found) {
340 w->num--;
344 void qemu_fd_register(int fd)
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);
351 static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
352 fd_set *xfds)
354 int nfds = -1;
355 int i;
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);
365 if (events & G_IO_OUT) {
366 FD_SET(fd, wfds);
367 nfds = MAX(nfds, fd);
369 if (events & G_IO_PRI) {
370 FD_SET(fd, xfds);
371 nfds = MAX(nfds, fd);
374 return nfds;
377 static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
378 fd_set *wfds, fd_set *xfds)
380 int i;
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;
387 if (FD_ISSET(fd, rfds)) {
388 revents |= G_IO_IN;
390 if (FD_ISSET(fd, wfds)) {
391 revents |= G_IO_OUT;
393 if (FD_ISSET(fd, xfds)) {
394 revents |= G_IO_PRI;
396 pfd->revents = revents & pfd->events;
400 static int os_host_main_loop_wait(int64_t timeout)
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;
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);
419 if (ret != 0) {
420 return ret;
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;
432 if (select_ret > 0) {
433 pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
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));
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;
447 if (poll_timeout < 0) {
448 poll_timeout_ns = -1;
449 } else {
450 poll_timeout_ns = (int64_t)poll_timeout * (int64_t)SCALE_MS;
453 poll_timeout_ns = qemu_soonest_timeout(poll_timeout_ns, timeout);
455 qemu_mutex_unlock_iothread();
456 g_poll_ret = qemu_poll_ns(poll_fds, n_poll_fds + w->num, poll_timeout_ns);
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;
463 for (i = 0; i < w->num; i++) {
464 if (w->revents[i] && w->func[i]) {
465 w->func[i](w->opaque[i]);
470 if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
471 g_main_context_dispatch(context);
474 return select_ret || g_poll_ret;
476 #endif
478 int main_loop_wait(int nonblocking)
480 int ret;
481 uint32_t timeout = UINT32_MAX;
482 int64_t timeout_ns;
484 if (nonblocking) {
485 timeout = 0;
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
495 if (timeout == UINT32_MAX) {
496 timeout_ns = -1;
497 } else {
498 timeout_ns = (uint64_t)timeout * (int64_t)(SCALE_MS);
501 timeout_ns = qemu_soonest_timeout(timeout_ns,
502 timerlistgroup_deadline_ns(
503 &main_loop_tlg));
505 ret = os_host_main_loop_wait(timeout_ns);
506 #ifdef CONFIG_SLIRP
507 slirp_pollfds_poll(gpollfds, (ret < 0));
508 #endif
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();
515 return ret;
518 /* Functions to operate on the main QEMU AioContext. */
520 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
522 return aio_bh_new(qemu_aio_context, cb, opaque);