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/*
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* QEMU System Emulator
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*
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* Copyright (c) 2003-2008 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h" |
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#include "qemu/timer.h" |
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#include "qemu/sockets.h" // struct in_addr needed for libslirp.h |
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#include "slirp/libslirp.h" |
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#include "qemu/main-loop.h" |
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#include "block/aio.h" |
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#ifndef _WIN32
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#include "qemu/compatfd.h" |
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/* If we have signalfd, we mask out the signals we want to handle and then
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* use signalfd to listen for them. We rely on whatever the current signal
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* handler is to dispatch the signals when we receive them.
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*/
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static void sigfd_handler(void *opaque) |
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{ |
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int fd = (intptr_t)opaque;
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struct qemu_signalfd_siginfo info;
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struct sigaction action;
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ssize_t len; |
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while (1) { |
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do {
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len = read(fd, &info, sizeof(info));
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} while (len == -1 && errno == EINTR); |
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if (len == -1 && errno == EAGAIN) { |
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break;
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} |
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if (len != sizeof(info)) { |
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printf("read from sigfd returned %zd: %m\n", len);
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return;
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} |
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sigaction(info.ssi_signo, NULL, &action);
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if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {
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action.sa_sigaction(info.ssi_signo, |
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(siginfo_t *)&info, NULL);
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} else if (action.sa_handler) { |
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action.sa_handler(info.ssi_signo); |
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} |
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} |
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} |
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static int qemu_signal_init(void) |
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{ |
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int sigfd;
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sigset_t set; |
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/*
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* SIG_IPI must be blocked in the main thread and must not be caught
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* by sigwait() in the signal thread. Otherwise, the cpu thread will
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* not catch it reliably.
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*/
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sigemptyset(&set); |
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sigaddset(&set, SIG_IPI); |
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sigaddset(&set, SIGIO); |
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sigaddset(&set, SIGALRM); |
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sigaddset(&set, SIGBUS); |
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pthread_sigmask(SIG_BLOCK, &set, NULL);
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sigdelset(&set, SIG_IPI); |
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sigfd = qemu_signalfd(&set); |
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if (sigfd == -1) { |
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fprintf(stderr, "failed to create signalfd\n");
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return -errno;
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} |
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fcntl_setfl(sigfd, O_NONBLOCK); |
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qemu_set_fd_handler2(sigfd, NULL, sigfd_handler, NULL, |
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(void *)(intptr_t)sigfd);
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return 0; |
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} |
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#else /* _WIN32 */ |
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static int qemu_signal_init(void) |
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{ |
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return 0; |
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} |
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#endif
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static AioContext *qemu_aio_context;
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AioContext *qemu_get_aio_context(void)
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{ |
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return qemu_aio_context;
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} |
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void qemu_notify_event(void) |
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{ |
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if (!qemu_aio_context) {
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return;
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} |
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aio_notify(qemu_aio_context); |
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} |
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static GArray *gpollfds;
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int qemu_init_main_loop(void) |
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{ |
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int ret;
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GSource *src; |
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init_clocks(); |
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ret = qemu_signal_init(); |
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if (ret) {
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return ret;
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} |
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gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
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qemu_aio_context = aio_context_new(); |
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src = aio_get_g_source(qemu_aio_context); |
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g_source_attach(src, NULL);
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g_source_unref(src); |
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return 0; |
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} |
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static int max_priority; |
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#ifndef _WIN32
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static int glib_pollfds_idx; |
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static int glib_n_poll_fds; |
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static void glib_pollfds_fill(int64_t *cur_timeout) |
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{ |
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GMainContext *context = g_main_context_default(); |
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int timeout = 0; |
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int64_t timeout_ns; |
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int n;
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g_main_context_prepare(context, &max_priority); |
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glib_pollfds_idx = gpollfds->len; |
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n = glib_n_poll_fds; |
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do {
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GPollFD *pfds; |
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glib_n_poll_fds = n; |
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g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds); |
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pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx); |
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n = g_main_context_query(context, max_priority, &timeout, pfds, |
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glib_n_poll_fds); |
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} while (n != glib_n_poll_fds);
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if (timeout < 0) { |
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timeout_ns = -1;
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} else {
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timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS; |
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} |
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*cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout); |
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} |
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static void glib_pollfds_poll(void) |
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{ |
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GMainContext *context = g_main_context_default(); |
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GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx); |
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if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
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g_main_context_dispatch(context); |
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} |
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} |
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#define MAX_MAIN_LOOP_SPIN (1000) |
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static int os_host_main_loop_wait(int64_t timeout) |
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{ |
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int ret;
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static int spin_counter; |
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glib_pollfds_fill(&timeout); |
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/* If the I/O thread is very busy or we are incorrectly busy waiting in
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* the I/O thread, this can lead to starvation of the BQL such that the
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* VCPU threads never run. To make sure we can detect the later case,
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* print a message to the screen. If we run into this condition, create
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* a fake timeout in order to give the VCPU threads a chance to run.
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*/
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if (!timeout && (spin_counter > MAX_MAIN_LOOP_SPIN)) {
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static bool notified; |
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if (!notified) {
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fprintf(stderr, |
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"main-loop: WARNING: I/O thread spun for %d iterations\n",
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MAX_MAIN_LOOP_SPIN); |
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notified = true;
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} |
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timeout = SCALE_MS; |
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} |
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if (timeout) {
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spin_counter = 0;
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qemu_mutex_unlock_iothread(); |
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} else {
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spin_counter++; |
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} |
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ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout); |
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if (timeout) {
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qemu_mutex_lock_iothread(); |
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} |
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glib_pollfds_poll(); |
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return ret;
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} |
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#else
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/***********************************************************/
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/* Polling handling */
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typedef struct PollingEntry { |
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PollingFunc *func; |
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void *opaque;
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struct PollingEntry *next;
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} PollingEntry; |
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static PollingEntry *first_polling_entry;
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int qemu_add_polling_cb(PollingFunc *func, void *opaque) |
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{ |
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PollingEntry **ppe, *pe; |
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pe = g_malloc0(sizeof(PollingEntry));
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pe->func = func; |
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pe->opaque = opaque; |
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for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next); |
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*ppe = pe; |
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return 0; |
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} |
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void qemu_del_polling_cb(PollingFunc *func, void *opaque) |
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{ |
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PollingEntry **ppe, *pe; |
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for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) { |
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pe = *ppe; |
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if (pe->func == func && pe->opaque == opaque) {
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*ppe = pe->next; |
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g_free(pe); |
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break;
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} |
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} |
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} |
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/***********************************************************/
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/* Wait objects support */
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typedef struct WaitObjects { |
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int num;
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int revents[MAXIMUM_WAIT_OBJECTS + 1]; |
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HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
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WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
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void *opaque[MAXIMUM_WAIT_OBJECTS + 1]; |
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} WaitObjects; |
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static WaitObjects wait_objects = {0}; |
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int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque) |
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{ |
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WaitObjects *w = &wait_objects; |
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if (w->num >= MAXIMUM_WAIT_OBJECTS) {
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return -1; |
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} |
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w->events[w->num] = handle; |
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w->func[w->num] = func; |
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w->opaque[w->num] = opaque; |
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w->revents[w->num] = 0;
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w->num++; |
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return 0; |
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} |
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void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque) |
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{ |
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int i, found;
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WaitObjects *w = &wait_objects; |
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found = 0;
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for (i = 0; i < w->num; i++) { |
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if (w->events[i] == handle) {
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found = 1;
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} |
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if (found) {
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w->events[i] = w->events[i + 1];
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w->func[i] = w->func[i + 1];
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w->opaque[i] = w->opaque[i + 1];
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w->revents[i] = w->revents[i + 1];
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} |
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} |
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if (found) {
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w->num--; |
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} |
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} |
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void qemu_fd_register(int fd) |
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{ |
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WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier), |
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FD_READ | FD_ACCEPT | FD_CLOSE | |
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FD_CONNECT | FD_WRITE | FD_OOB); |
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} |
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static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds, |
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fd_set *xfds) |
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{ |
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int nfds = -1; |
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int i;
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for (i = 0; i < pollfds->len; i++) { |
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GPollFD *pfd = &g_array_index(pollfds, GPollFD, i); |
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int fd = pfd->fd;
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int events = pfd->events;
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if (events & G_IO_IN) {
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FD_SET(fd, rfds); |
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nfds = MAX(nfds, fd); |
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} |
342 |
if (events & G_IO_OUT) {
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FD_SET(fd, wfds); |
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nfds = MAX(nfds, fd); |
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} |
346 |
if (events & G_IO_PRI) {
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FD_SET(fd, xfds); |
348 |
nfds = MAX(nfds, fd); |
349 |
} |
350 |
} |
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return nfds;
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} |
353 |
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static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds, |
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fd_set *wfds, fd_set *xfds) |
356 |
{ |
357 |
int i;
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358 |
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for (i = 0; i < pollfds->len; i++) { |
360 |
GPollFD *pfd = &g_array_index(pollfds, GPollFD, i); |
361 |
int fd = pfd->fd;
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int revents = 0; |
363 |
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364 |
if (FD_ISSET(fd, rfds)) {
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revents |= G_IO_IN; |
366 |
} |
367 |
if (FD_ISSET(fd, wfds)) {
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revents |= G_IO_OUT; |
369 |
} |
370 |
if (FD_ISSET(fd, xfds)) {
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revents |= G_IO_PRI; |
372 |
} |
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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;
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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;
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390 |
|
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/* XXX: need to suppress polling by better using win32 events */
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ret = 0;
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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 |
} |