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
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"
34 #include "qemu/compatfd.h"
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.
40 static void sigfd_handler(void *opaque)
42 int fd = (intptr_t)opaque;
43 struct qemu_signalfd_siginfo info;
44 struct sigaction action;
49 len = read(fd, &info, sizeof(info));
50 } while (len == -1 && errno == EINTR);
52 if (len == -1 && errno == EAGAIN) {
56 if (len != sizeof(info)) {
57 printf("read from sigfd returned %zd: %m\n", len);
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);
71 static int qemu_signal_init(void)
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.
82 sigaddset(&set, SIG_IPI);
83 sigaddset(&set, SIGIO);
84 sigaddset(&set, SIGALRM);
85 sigaddset(&set, SIGBUS);
86 pthread_sigmask(SIG_BLOCK, &set, NULL);
88 sigdelset(&set, SIG_IPI);
89 sigfd = qemu_signalfd(&set);
91 fprintf(stderr, "failed to create signalfd\n");
95 fcntl_setfl(sigfd, O_NONBLOCK);
97 qemu_set_fd_handler2(sigfd, NULL, sigfd_handler, NULL,
98 (void *)(intptr_t)sigfd);
105 static int qemu_signal_init(void)
111 static AioContext *qemu_aio_context;
113 AioContext *qemu_get_aio_context(void)
115 return qemu_aio_context;
118 void qemu_notify_event(void)
120 if (!qemu_aio_context) {
123 aio_notify(qemu_aio_context);
126 static GArray *gpollfds;
128 int qemu_init_main_loop(void)
134 if (init_timer_alarm() < 0) {
135 fprintf(stderr, "could not initialize alarm timer\n");
139 ret = qemu_signal_init();
144 gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
145 qemu_aio_context = aio_context_new();
146 src = aio_get_g_source(qemu_aio_context);
147 g_source_attach(src, NULL);
152 static int max_priority;
155 static int glib_pollfds_idx;
156 static int glib_n_poll_fds;
158 static void glib_pollfds_fill(int64_t *cur_timeout)
160 GMainContext *context = g_main_context_default();
165 g_main_context_prepare(context, &max_priority);
167 glib_pollfds_idx = gpollfds->len;
172 g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds);
173 pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
174 n = g_main_context_query(context, max_priority, &timeout, pfds,
176 } while (n != glib_n_poll_fds);
181 timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS;
184 *cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout);
187 static void glib_pollfds_poll(void)
189 GMainContext *context = g_main_context_default();
190 GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
192 if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
193 g_main_context_dispatch(context);
197 #define MAX_MAIN_LOOP_SPIN (1000)
199 static int os_host_main_loop_wait(int64_t timeout)
202 static int spin_counter;
204 glib_pollfds_fill(&timeout);
206 /* If the I/O thread is very busy or we are incorrectly busy waiting in
207 * the I/O thread, this can lead to starvation of the BQL such that the
208 * VCPU threads never run. To make sure we can detect the later case,
209 * print a message to the screen. If we run into this condition, create
210 * a fake timeout in order to give the VCPU threads a chance to run.
212 if (!timeout && (spin_counter > MAX_MAIN_LOOP_SPIN)) {
213 static bool notified;
217 "main-loop: WARNING: I/O thread spun for %d iterations\n",
227 qemu_mutex_unlock_iothread();
232 ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout);
235 qemu_mutex_lock_iothread();
242 /***********************************************************/
243 /* Polling handling */
245 typedef struct PollingEntry {
248 struct PollingEntry *next;
251 static PollingEntry *first_polling_entry;
253 int qemu_add_polling_cb(PollingFunc *func, void *opaque)
255 PollingEntry **ppe, *pe;
256 pe = g_malloc0(sizeof(PollingEntry));
259 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);
264 void qemu_del_polling_cb(PollingFunc *func, void *opaque)
266 PollingEntry **ppe, *pe;
267 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {
269 if (pe->func == func && pe->opaque == opaque) {
277 /***********************************************************/
278 /* Wait objects support */
279 typedef struct WaitObjects {
281 int revents[MAXIMUM_WAIT_OBJECTS + 1];
282 HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
283 WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
284 void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
287 static WaitObjects wait_objects = {0};
289 int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
291 WaitObjects *w = &wait_objects;
292 if (w->num >= MAXIMUM_WAIT_OBJECTS) {
295 w->events[w->num] = handle;
296 w->func[w->num] = func;
297 w->opaque[w->num] = opaque;
298 w->revents[w->num] = 0;
303 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
306 WaitObjects *w = &wait_objects;
309 for (i = 0; i < w->num; i++) {
310 if (w->events[i] == handle) {
314 w->events[i] = w->events[i + 1];
315 w->func[i] = w->func[i + 1];
316 w->opaque[i] = w->opaque[i + 1];
317 w->revents[i] = w->revents[i + 1];
325 void qemu_fd_register(int fd)
327 WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
328 FD_READ | FD_ACCEPT | FD_CLOSE |
329 FD_CONNECT | FD_WRITE | FD_OOB);
332 static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
338 for (i = 0; i < pollfds->len; i++) {
339 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
341 int events = pfd->events;
342 if (events & G_IO_IN) {
344 nfds = MAX(nfds, fd);
346 if (events & G_IO_OUT) {
348 nfds = MAX(nfds, fd);
350 if (events & G_IO_PRI) {
352 nfds = MAX(nfds, fd);
358 static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
359 fd_set *wfds, fd_set *xfds)
363 for (i = 0; i < pollfds->len; i++) {
364 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
368 if (FD_ISSET(fd, rfds)) {
371 if (FD_ISSET(fd, wfds)) {
374 if (FD_ISSET(fd, xfds)) {
377 pfd->revents = revents & pfd->events;
381 static int os_host_main_loop_wait(int64_t timeout)
383 GMainContext *context = g_main_context_default();
384 GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
386 int g_poll_ret, ret, i, n_poll_fds;
388 WaitObjects *w = &wait_objects;
390 int64_t poll_timeout_ns;
391 static struct timeval tv0;
392 fd_set rfds, wfds, xfds;
395 /* XXX: need to suppress polling by better using win32 events */
397 for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
398 ret |= pe->func(pe->opaque);
407 nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
409 select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
410 if (select_ret != 0) {
413 if (select_ret > 0) {
414 pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
418 g_main_context_prepare(context, &max_priority);
419 n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
420 poll_fds, ARRAY_SIZE(poll_fds));
421 g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));
423 for (i = 0; i < w->num; i++) {
424 poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i];
425 poll_fds[n_poll_fds + i].events = G_IO_IN;
428 if (poll_timeout < 0) {
429 poll_timeout_ns = -1;
431 poll_timeout_ns = (int64_t)poll_timeout * (int64_t)SCALE_MS;
434 poll_timeout_ns = qemu_soonest_timeout(poll_timeout_ns, timeout);
436 qemu_mutex_unlock_iothread();
437 g_poll_ret = qemu_poll_ns(poll_fds, n_poll_fds + w->num, poll_timeout_ns);
439 qemu_mutex_lock_iothread();
440 if (g_poll_ret > 0) {
441 for (i = 0; i < w->num; i++) {
442 w->revents[i] = poll_fds[n_poll_fds + i].revents;
444 for (i = 0; i < w->num; i++) {
445 if (w->revents[i] && w->func[i]) {
446 w->func[i](w->opaque[i]);
451 if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
452 g_main_context_dispatch(context);
455 return select_ret || g_poll_ret;
459 int main_loop_wait(int nonblocking)
462 uint32_t timeout = UINT32_MAX;
469 /* poll any events */
470 g_array_set_size(gpollfds, 0); /* reset for new iteration */
471 /* XXX: separate device handlers from system ones */
473 slirp_update_timeout(&timeout);
474 slirp_pollfds_fill(gpollfds);
476 qemu_iohandler_fill(gpollfds);
478 if (timeout == UINT32_MAX) {
481 timeout_ns = (uint64_t)timeout * (int64_t)(SCALE_MS);
484 timeout_ns = qemu_soonest_timeout(timeout_ns,
485 timerlistgroup_deadline_ns(
488 ret = os_host_main_loop_wait(timeout_ns);
489 qemu_iohandler_poll(gpollfds, ret);
491 slirp_pollfds_poll(gpollfds, (ret < 0));
494 qemu_run_all_timers();
499 /* Functions to operate on the main QEMU AioContext. */
501 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
503 return aio_bh_new(qemu_aio_context, cb, opaque);
506 bool qemu_aio_wait(void)
508 return aio_poll(qemu_aio_context, true);
512 void qemu_aio_set_fd_handler(int fd,
517 aio_set_fd_handler(qemu_aio_context, fd, io_read, io_write, opaque);
521 void qemu_aio_set_event_notifier(EventNotifier *notifier,
522 EventNotifierHandler *io_read)
524 aio_set_event_notifier(qemu_aio_context, notifier, io_read);