--- /dev/null
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu-common.h"
+#include "qemu/timer.h"
+#include "qemu/sockets.h" // struct in_addr needed for libslirp.h
+#include "sysemu/qtest.h"
+#include "slirp/libslirp.h"
+#include "qemu/main-loop.h"
+#include "block/aio.h"
+
+#ifndef _WIN32
+
+#include "qemu/compatfd.h"
+
+/* If we have signalfd, we mask out the signals we want to handle and then
+ * use signalfd to listen for them. We rely on whatever the current signal
+ * handler is to dispatch the signals when we receive them.
+ */
+static void sigfd_handler(void *opaque)
+{
+ int fd = (intptr_t)opaque;
+ struct qemu_signalfd_siginfo info;
+ struct sigaction action;
+ ssize_t len;
+
+ while (1) {
+ do {
+ len = read(fd, &info, sizeof(info));
+ } while (len == -1 && errno == EINTR);
+
+ if (len == -1 && errno == EAGAIN) {
+ break;
+ }
+
+ if (len != sizeof(info)) {
+ printf("read from sigfd returned %zd: %m\n", len);
+ return;
+ }
+
+ sigaction(info.ssi_signo, NULL, &action);
+ if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {
+ action.sa_sigaction(info.ssi_signo,
+ (siginfo_t *)&info, NULL);
+ } else if (action.sa_handler) {
+ action.sa_handler(info.ssi_signo);
+ }
+ }
+}
+
+static int qemu_signal_init(void)
+{
+ int sigfd;
+ sigset_t set;
+
+ /*
+ * SIG_IPI must be blocked in the main thread and must not be caught
+ * by sigwait() in the signal thread. Otherwise, the cpu thread will
+ * not catch it reliably.
+ */
+ sigemptyset(&set);
+ sigaddset(&set, SIG_IPI);
+ sigaddset(&set, SIGIO);
+ sigaddset(&set, SIGALRM);
+ sigaddset(&set, SIGBUS);
+ /* SIGINT cannot be handled via signalfd, so that ^C can be used
+ * to interrupt QEMU when it is being run under gdb. SIGHUP and
+ * SIGTERM are also handled asynchronously, even though it is not
+ * strictly necessary, because they use the same handler as SIGINT.
+ */
+ pthread_sigmask(SIG_BLOCK, &set, NULL);
+
+ sigdelset(&set, SIG_IPI);
+ sigfd = qemu_signalfd(&set);
+ if (sigfd == -1) {
+ fprintf(stderr, "failed to create signalfd\n");
+ return -errno;
+ }
+
+ fcntl_setfl(sigfd, O_NONBLOCK);
+
+ qemu_set_fd_handler(sigfd, sigfd_handler, NULL, (void *)(intptr_t)sigfd);
+
+ return 0;
+}
+
+#else /* _WIN32 */
+
+static int qemu_signal_init(void)
+{
+ return 0;
+}
+#endif
+
+static AioContext *qemu_aio_context;
+static QEMUBH *qemu_notify_bh;
+
+static void notify_event_cb(void *opaque)
+{
+ /* No need to do anything; this bottom half is only used to
+ * kick the kernel out of ppoll/poll/WaitForMultipleObjects.
+ */
+}
+
+AioContext *qemu_get_aio_context(void)
+{
+ return qemu_aio_context;
+}
+
+void qemu_notify_event(void)
+{
+ if (!qemu_aio_context) {
+ return;
+ }
+ qemu_bh_schedule(qemu_notify_bh);
+}
+
+static GArray *gpollfds;
+
+int qemu_init_main_loop(Error **errp)
+{
+ int ret;
+ GSource *src;
+ Error *local_error = NULL;
+
+ init_clocks();
+
+ ret = qemu_signal_init();
+ if (ret) {
+ return ret;
+ }
+
+ qemu_aio_context = aio_context_new(&local_error);
+ qemu_notify_bh = qemu_bh_new(notify_event_cb, NULL);
+ if (!qemu_aio_context) {
+ error_propagate(errp, local_error);
+ return -EMFILE;
+ }
+ gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
+ src = aio_get_g_source(qemu_aio_context);
+ g_source_attach(src, NULL);
+ g_source_unref(src);
+ return 0;
+}
+
+static int max_priority;
+
+#ifndef _WIN32
+static int glib_pollfds_idx;
+static int glib_n_poll_fds;
+
+static void glib_pollfds_fill(int64_t *cur_timeout)
+{
+ GMainContext *context = g_main_context_default();
+ int timeout = 0;
+ int64_t timeout_ns;
+ int n;
+
+ g_main_context_prepare(context, &max_priority);
+
+ glib_pollfds_idx = gpollfds->len;
+ n = glib_n_poll_fds;
+ do {
+ GPollFD *pfds;
+ glib_n_poll_fds = n;
+ g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds);
+ pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
+ n = g_main_context_query(context, max_priority, &timeout, pfds,
+ glib_n_poll_fds);
+ } while (n != glib_n_poll_fds);
+
+ if (timeout < 0) {
+ timeout_ns = -1;
+ } else {
+ timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS;
+ }
+
+ *cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout);
+}
+
+static void glib_pollfds_poll(void)
+{
+ GMainContext *context = g_main_context_default();
+ GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
+
+ if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
+ g_main_context_dispatch(context);
+ }
+}
+
+#define MAX_MAIN_LOOP_SPIN (1000)
+
+static int os_host_main_loop_wait(int64_t timeout)
+{
+ int ret;
+ static int spin_counter;
+
+ glib_pollfds_fill(&timeout);
+
+ /* If the I/O thread is very busy or we are incorrectly busy waiting in
+ * the I/O thread, this can lead to starvation of the BQL such that the
+ * VCPU threads never run. To make sure we can detect the later case,
+ * print a message to the screen. If we run into this condition, create
+ * a fake timeout in order to give the VCPU threads a chance to run.
+ */
+ if (!timeout && (spin_counter > MAX_MAIN_LOOP_SPIN)) {
+ static bool notified;
+
+ if (!notified && !qtest_enabled()) {
+ fprintf(stderr,
+ "main-loop: WARNING: I/O thread spun for %d iterations\n",
+ MAX_MAIN_LOOP_SPIN);
+ notified = true;
+ }
+
+ timeout = SCALE_MS;
+ }
+
+ if (timeout) {
+ spin_counter = 0;
+ qemu_mutex_unlock_iothread();
+ } else {
+ spin_counter++;
+ }
+
+ ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout);
+
+ if (timeout) {
+ qemu_mutex_lock_iothread();
+ }
+
+ glib_pollfds_poll();
+ return ret;
+}
+#else
+/***********************************************************/
+/* Polling handling */
+
+typedef struct PollingEntry {
+ PollingFunc *func;
+ void *opaque;
+ struct PollingEntry *next;
+} PollingEntry;
+
+static PollingEntry *first_polling_entry;
+
+int qemu_add_polling_cb(PollingFunc *func, void *opaque)
+{
+ PollingEntry **ppe, *pe;
+ pe = g_malloc0(sizeof(PollingEntry));
+ pe->func = func;
+ pe->opaque = opaque;
+ for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);
+ *ppe = pe;
+ return 0;
+}
+
+void qemu_del_polling_cb(PollingFunc *func, void *opaque)
+{
+ PollingEntry **ppe, *pe;
+ for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {
+ pe = *ppe;
+ if (pe->func == func && pe->opaque == opaque) {
+ *ppe = pe->next;
+ g_free(pe);
+ break;
+ }
+ }
+}
+
+/***********************************************************/
+/* Wait objects support */
+typedef struct WaitObjects {
+ int num;
+ int revents[MAXIMUM_WAIT_OBJECTS + 1];
+ HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
+ WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
+ void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
+} WaitObjects;
+
+static WaitObjects wait_objects = {0};
+
+int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
+{
+ WaitObjects *w = &wait_objects;
+ if (w->num >= MAXIMUM_WAIT_OBJECTS) {
+ return -1;
+ }
+ w->events[w->num] = handle;
+ w->func[w->num] = func;
+ w->opaque[w->num] = opaque;
+ w->revents[w->num] = 0;
+ w->num++;
+ return 0;
+}
+
+void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
+{
+ int i, found;
+ WaitObjects *w = &wait_objects;
+
+ found = 0;
+ for (i = 0; i < w->num; i++) {
+ if (w->events[i] == handle) {
+ found = 1;
+ }
+ if (found) {
+ w->events[i] = w->events[i + 1];
+ w->func[i] = w->func[i + 1];
+ w->opaque[i] = w->opaque[i + 1];
+ w->revents[i] = w->revents[i + 1];
+ }
+ }
+ if (found) {
+ w->num--;
+ }
+}
+
+void qemu_fd_register(int fd)
+{
+ WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
+ FD_READ | FD_ACCEPT | FD_CLOSE |
+ FD_CONNECT | FD_WRITE | FD_OOB);
+}
+
+static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
+ fd_set *xfds)
+{
+ int nfds = -1;
+ int i;
+
+ for (i = 0; i < pollfds->len; i++) {
+ GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
+ int fd = pfd->fd;
+ int events = pfd->events;
+ if (events & G_IO_IN) {
+ FD_SET(fd, rfds);
+ nfds = MAX(nfds, fd);
+ }
+ if (events & G_IO_OUT) {
+ FD_SET(fd, wfds);
+ nfds = MAX(nfds, fd);
+ }
+ if (events & G_IO_PRI) {
+ FD_SET(fd, xfds);
+ nfds = MAX(nfds, fd);
+ }
+ }
+ return nfds;
+}
+
+static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
+ fd_set *wfds, fd_set *xfds)
+{
+ int i;
+
+ for (i = 0; i < pollfds->len; i++) {
+ GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
+ int fd = pfd->fd;
+ int revents = 0;
+
+ if (FD_ISSET(fd, rfds)) {
+ revents |= G_IO_IN;
+ }
+ if (FD_ISSET(fd, wfds)) {
+ revents |= G_IO_OUT;
+ }
+ if (FD_ISSET(fd, xfds)) {
+ revents |= G_IO_PRI;
+ }
+ pfd->revents = revents & pfd->events;
+ }
+}
+
+static int os_host_main_loop_wait(int64_t timeout)
+{
+ GMainContext *context = g_main_context_default();
+ GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
+ int select_ret = 0;
+ int g_poll_ret, ret, i, n_poll_fds;
+ PollingEntry *pe;
+ WaitObjects *w = &wait_objects;
+ gint poll_timeout;
+ int64_t poll_timeout_ns;
+ static struct timeval tv0;
+ fd_set rfds, wfds, xfds;
+ int nfds;
+
+ /* XXX: need to suppress polling by better using win32 events */
+ ret = 0;
+ for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
+ ret |= pe->func(pe->opaque);
+ }
+ if (ret != 0) {
+ return ret;
+ }
+
+ FD_ZERO(&rfds);
+ FD_ZERO(&wfds);
+ FD_ZERO(&xfds);
+ nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
+ if (nfds >= 0) {
+ select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
+ if (select_ret != 0) {
+ timeout = 0;
+ }
+ if (select_ret > 0) {
+ pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
+ }
+ }
+
+ g_main_context_prepare(context, &max_priority);
+ n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
+ poll_fds, ARRAY_SIZE(poll_fds));
+ g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));
+
+ for (i = 0; i < w->num; i++) {
+ poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i];
+ poll_fds[n_poll_fds + i].events = G_IO_IN;
+ }
+
+ if (poll_timeout < 0) {
+ poll_timeout_ns = -1;
+ } else {
+ poll_timeout_ns = (int64_t)poll_timeout * (int64_t)SCALE_MS;
+ }
+
+ poll_timeout_ns = qemu_soonest_timeout(poll_timeout_ns, timeout);
+
+ qemu_mutex_unlock_iothread();
+ g_poll_ret = qemu_poll_ns(poll_fds, n_poll_fds + w->num, poll_timeout_ns);
+
+ qemu_mutex_lock_iothread();
+ if (g_poll_ret > 0) {
+ for (i = 0; i < w->num; i++) {
+ w->revents[i] = poll_fds[n_poll_fds + i].revents;
+ }
+ for (i = 0; i < w->num; i++) {
+ if (w->revents[i] && w->func[i]) {
+ w->func[i](w->opaque[i]);
+ }
+ }
+ }
+
+ if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
+ g_main_context_dispatch(context);
+ }
+
+ return select_ret || g_poll_ret;
+}
+#endif
+
+int main_loop_wait(int nonblocking)
+{
+ int ret;
+ uint32_t timeout = UINT32_MAX;
+ int64_t timeout_ns;
+
+ if (nonblocking) {
+ timeout = 0;
+ }
+
+ /* poll any events */
+ g_array_set_size(gpollfds, 0); /* reset for new iteration */
+ /* XXX: separate device handlers from system ones */
+#ifdef CONFIG_SLIRP
+ slirp_pollfds_fill(gpollfds, &timeout);
+#endif
+ qemu_iohandler_fill(gpollfds);
+
+ if (timeout == UINT32_MAX) {
+ timeout_ns = -1;
+ } else {
+ timeout_ns = (uint64_t)timeout * (int64_t)(SCALE_MS);
+ }
+
+ timeout_ns = qemu_soonest_timeout(timeout_ns,
+ timerlistgroup_deadline_ns(
+ &main_loop_tlg));
+
+ ret = os_host_main_loop_wait(timeout_ns);
+ qemu_iohandler_poll(gpollfds, ret);
+#ifdef CONFIG_SLIRP
+ slirp_pollfds_poll(gpollfds, (ret < 0));
+#endif
+
+ qemu_clock_run_all_timers();
+
+ return ret;
+}
+
+/* Functions to operate on the main QEMU AioContext. */
+
+QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
+{
+ return aio_bh_new(qemu_aio_context, cb, opaque);
+}
Code Review / kvmfornfv.git / blobdiff