diff options
| -rw-r--r-- | async.c | 1 | ||||
| -rw-r--r-- | cpus.c | 7 | ||||
| -rw-r--r-- | cpus.h | 1 | ||||
| -rw-r--r-- | iohandler.c | 1 | ||||
| -rw-r--r-- | main-loop.h | 327 | ||||
| -rw-r--r-- | qemu-char.h | 12 | ||||
| -rw-r--r-- | qemu-common.h | 30 | ||||
| -rw-r--r-- | qemu-coroutine-lock.c | 1 | ||||
| -rw-r--r-- | qemu-os-win32.h | 15 | ||||
| -rw-r--r-- | qemu-timer.h | 1 | ||||
| -rw-r--r-- | sysemu.h | 3 | ||||
| -rw-r--r-- | vl.c | 1 |
12 files changed, 336 insertions, 64 deletions
@@ -24,6 +24,7 @@ #include "qemu-common.h" #include "qemu-aio.h" +#include "main-loop.h" /* Anchor of the list of Bottom Halves belonging to the context */ static struct QEMUBH *first_bh; @@ -33,17 +33,12 @@ #include "qemu-thread.h" #include "cpus.h" +#include "main-loop.h" #ifndef _WIN32 #include "compatfd.h" #endif -#ifdef SIGRTMIN -#define SIG_IPI (SIGRTMIN+4) -#else -#define SIG_IPI SIGUSR1 -#endif - #ifdef CONFIG_LINUX #include <sys/prctl.h> @@ -2,7 +2,6 @@ #define QEMU_CPUS_H /* cpus.c */ -int qemu_init_main_loop(void); void qemu_main_loop_start(void); void resume_all_vcpus(void); void pause_all_vcpus(void); diff --git a/iohandler.c b/iohandler.c index 4cc1c5ade6..687dc565a4 100644 --- a/iohandler.c +++ b/iohandler.c @@ -26,6 +26,7 @@ #include "qemu-common.h" #include "qemu-char.h" #include "qemu-queue.h" +#include "main-loop.h" #ifndef _WIN32 #include <sys/wait.h> diff --git a/main-loop.h b/main-loop.h new file mode 100644 index 0000000000..a73b9c0bbe --- /dev/null +++ b/main-loop.h @@ -0,0 +1,327 @@ +/* + * 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. + */ + +#ifndef QEMU_MAIN_LOOP_H +#define QEMU_MAIN_LOOP_H 1 + +#ifdef SIGRTMIN +#define SIG_IPI (SIGRTMIN+4) +#else +#define SIG_IPI SIGUSR1 +#endif + +/** + * qemu_init_main_loop: Set up the process so that it can run the main loop. + * + * This includes setting up signal handlers. It should be called before + * any other threads are created. In addition, threads other than the + * main one should block signals that are trapped by the main loop. + * For simplicity, you can consider these signals to be safe: SIGUSR1, + * SIGUSR2, thread signals (SIGFPE, SIGILL, SIGSEGV, SIGBUS) and real-time + * signals if available. Remember that Windows in practice does not have + * signals, though. + */ +int qemu_init_main_loop(void); + +/** + * main_loop_wait: Run one iteration of the main loop. + * + * If @nonblocking is true, poll for events, otherwise suspend until + * one actually occurs. The main loop usually consists of a loop that + * repeatedly calls main_loop_wait(false). + * + * Main loop services include file descriptor callbacks, bottom halves + * and timers (defined in qemu-timer.h). Bottom halves are similar to timers + * that execute immediately, but have a lower overhead and scheduling them + * is wait-free, thread-safe and signal-safe. + * + * It is sometimes useful to put a whole program in a coroutine. In this + * case, the coroutine actually should be started from within the main loop, + * so that the main loop can run whenever the coroutine yields. To do this, + * you can use a bottom half to enter the coroutine as soon as the main loop + * starts: + * + * void enter_co_bh(void *opaque) { + * QEMUCoroutine *co = opaque; + * qemu_coroutine_enter(co, NULL); + * } + * + * ... + * QEMUCoroutine *co = qemu_coroutine_create(coroutine_entry); + * QEMUBH *start_bh = qemu_bh_new(enter_co_bh, co); + * qemu_bh_schedule(start_bh); + * while (...) { + * main_loop_wait(false); + * } + * + * (In the future we may provide a wrapper for this). + * + * @nonblocking: Whether the caller should block until an event occurs. + */ +int main_loop_wait(int nonblocking); + +/** + * qemu_notify_event: Force processing of pending events. + * + * Similar to signaling a condition variable, qemu_notify_event forces + * main_loop_wait to look at pending events and exit. The caller of + * main_loop_wait will usually call it again very soon, so qemu_notify_event + * also has the side effect of recalculating the sets of file descriptors + * that the main loop waits for. + * + * Calling qemu_notify_event is rarely necessary, because main loop + * services (bottom halves and timers) call it themselves. One notable + * exception occurs when using qemu_set_fd_handler2 (see below). + */ +void qemu_notify_event(void); + +#ifdef _WIN32 +/* return TRUE if no sleep should be done afterwards */ +typedef int PollingFunc(void *opaque); + +/** + * qemu_add_polling_cb: Register a Windows-specific polling callback + * + * Currently, under Windows some events are polled rather than waited for. + * Polling callbacks do not ensure that @func is called timely, because + * the main loop might wait for an arbitrarily long time. If possible, + * you should instead create a separate thread that does a blocking poll + * and set a Win32 event object. The event can then be passed to + * qemu_add_wait_object. + * + * Polling callbacks really have nothing Windows specific in them, but + * as they are a hack and are currenly not necessary under POSIX systems, + * they are only available when QEMU is running under Windows. + * + * @func: The function that does the polling, and returns 1 to force + * immediate completion of main_loop_wait. + * @opaque: A pointer-size value that is passed to @func. + */ +int qemu_add_polling_cb(PollingFunc *func, void *opaque); + +/** + * qemu_del_polling_cb: Unregister a Windows-specific polling callback + * + * This function removes a callback that was registered with + * qemu_add_polling_cb. + * + * @func: The function that was passed to qemu_add_polling_cb. + * @opaque: A pointer-size value that was passed to qemu_add_polling_cb. + */ +void qemu_del_polling_cb(PollingFunc *func, void *opaque); + +/* Wait objects handling */ +typedef void WaitObjectFunc(void *opaque); + +/** + * qemu_add_wait_object: Register a callback for a Windows handle + * + * Under Windows, the iohandler mechanism can only be used with sockets. + * QEMU must use the WaitForMultipleObjects API to wait on other handles. + * This function registers a #HANDLE with QEMU, so that it will be included + * in the main loop's calls to WaitForMultipleObjects. When the handle + * is in a signaled state, QEMU will call @func. + * + * @handle: The Windows handle to be observed. + * @func: A function to be called when @handle is in a signaled state. + * @opaque: A pointer-size value that is passed to @func. + */ +int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque); + +/** + * qemu_del_wait_object: Unregister a callback for a Windows handle + * + * This function removes a callback that was registered with + * qemu_add_wait_object. + * + * @func: The function that was passed to qemu_add_wait_object. + * @opaque: A pointer-size value that was passed to qemu_add_wait_object. + */ +void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque); +#endif + +/* async I/O support */ + +typedef void IOReadHandler(void *opaque, const uint8_t *buf, int size); +typedef int IOCanReadHandler(void *opaque); +typedef void IOHandler(void *opaque); + +/** + * qemu_set_fd_handler2: Register a file descriptor with the main loop + * + * This function tells the main loop to wake up whenever one of the + * following conditions is true: + * + * 1) if @fd_write is not %NULL, when the file descriptor is writable; + * + * 2) if @fd_read is not %NULL, when the file descriptor is readable. + * + * @fd_read_poll can be used to disable the @fd_read callback temporarily. + * This is useful to avoid calling qemu_set_fd_handler2 every time the + * client becomes interested in reading (or dually, stops being interested). + * A typical example is when @fd is a listening socket and you want to bound + * the number of active clients. Remember to call qemu_notify_event whenever + * the condition may change from %false to %true. + * + * The callbacks that are set up by qemu_set_fd_handler2 are level-triggered. + * If @fd_read does not read from @fd, or @fd_write does not write to @fd + * until its buffers are full, they will be called again on the next + * iteration. + * + * @fd: The file descriptor to be observed. Under Windows it must be + * a #SOCKET. + * + * @fd_read_poll: A function that returns 1 if the @fd_read callback + * should be fired. If the function returns 0, the main loop will not + * end its iteration even if @fd becomes readable. + * + * @fd_read: A level-triggered callback that is fired if @fd is readable + * at the beginning of a main loop iteration, or if it becomes readable + * during one. + * + * @fd_write: A level-triggered callback that is fired when @fd is writable + * at the beginning of a main loop iteration, or if it becomes writable + * during one. + * + * @opaque: A pointer-sized value that is passed to @fd_read_poll, + * @fd_read and @fd_write. + */ +int qemu_set_fd_handler2(int fd, + IOCanReadHandler *fd_read_poll, + IOHandler *fd_read, + IOHandler *fd_write, + void *opaque); + +/** + * qemu_set_fd_handler: Register a file descriptor with the main loop + * + * This function tells the main loop to wake up whenever one of the + * following conditions is true: + * + * 1) if @fd_write is not %NULL, when the file descriptor is writable; + * + * 2) if @fd_read is not %NULL, when the file descriptor is readable. + * + * The callbacks that are set up by qemu_set_fd_handler are level-triggered. + * If @fd_read does not read from @fd, or @fd_write does not write to @fd + * until its buffers are full, they will be called again on the next + * iteration. + * + * @fd: The file descriptor to be observed. Under Windows it must be + * a #SOCKET. + * + * @fd_read: A level-triggered callback that is fired if @fd is readable + * at the beginning of a main loop iteration, or if it becomes readable + * during one. + * + * @fd_write: A level-triggered callback that is fired when @fd is writable + * at the beginning of a main loop iteration, or if it becomes writable + * during one. + * + * @opaque: A pointer-sized value that is passed to @fd_read and @fd_write. + */ +int qemu_set_fd_handler(int fd, + IOHandler *fd_read, + IOHandler *fd_write, + void *opaque); + +typedef struct QEMUBH QEMUBH; +typedef void QEMUBHFunc(void *opaque); + +/** + * qemu_bh_new: Allocate a new bottom half structure. + * + * Bottom halves are lightweight callbacks whose invocation is guaranteed + * to be wait-free, thread-safe and signal-safe. The #QEMUBH structure + * is opaque and must be allocated prior to its use. + */ +QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque); + +/** + * qemu_bh_schedule: Schedule a bottom half. + * + * Scheduling a bottom half interrupts the main loop and causes the + * execution of the callback that was passed to qemu_bh_new. + * + * Bottom halves that are scheduled from a bottom half handler are instantly + * invoked. This can create an infinite loop if a bottom half handler + * schedules itself. + * + * @bh: The bottom half to be scheduled. + */ +void qemu_bh_schedule(QEMUBH *bh); + +/** + * qemu_bh_cancel: Cancel execution of a bottom half. + * + * Canceling execution of a bottom half undoes the effect of calls to + * qemu_bh_schedule without freeing its resources yet. While cancellation + * itself is also wait-free and thread-safe, it can of course race with the + * loop that executes bottom halves unless you are holding the iothread + * mutex. This makes it mostly useless if you are not holding the mutex. + * + * @bh: The bottom half to be canceled. + */ +void qemu_bh_cancel(QEMUBH *bh); + +/** + *qemu_bh_delete: Cancel execution of a bottom half and free its resources. + * + * Deleting a bottom half frees the memory that was allocated for it by + * qemu_bh_new. It also implies canceling the bottom half if it was + * scheduled. + * + * @bh: The bottom half to be deleted. + */ +void qemu_bh_delete(QEMUBH *bh); + +#ifdef CONFIG_POSIX +/** + * qemu_add_child_watch: Register a child process for reaping. + * + * Under POSIX systems, a parent process must read the exit status of + * its child processes using waitpid, or the operating system will not + * free some of the resources attached to that process. + * + * This function directs the QEMU main loop to observe a child process + * and call waitpid as soon as it exits; the watch is then removed + * automatically. It is useful whenever QEMU forks a child process + * but will find out about its termination by other means such as a + * "broken pipe". + * + * @pid: The pid that QEMU should observe. + */ +int qemu_add_child_watch(pid_t pid); +#endif + +/* internal interfaces */ + +void qemu_iohandler_fill(int *pnfds, fd_set *readfds, fd_set *writefds, fd_set *xfds); +void qemu_iohandler_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds, int rc); + +void qemu_bh_schedule_idle(QEMUBH *bh); +int qemu_bh_poll(void); +void qemu_bh_update_timeout(int *timeout); + +#endif diff --git a/qemu-char.h b/qemu-char.h index eebbdd8f01..7efcf99f53 100644 --- a/qemu-char.h +++ b/qemu-char.h @@ -7,6 +7,7 @@ #include "qemu-config.h" #include "qobject.h" #include "qstring.h" +#include "main-loop.h" /* character device */ @@ -237,15 +238,4 @@ void qemu_chr_close_mem(CharDriverState *chr); QString *qemu_chr_mem_to_qs(CharDriverState *chr); size_t qemu_chr_mem_osize(const CharDriverState *chr); -/* async I/O support */ - -int qemu_set_fd_handler2(int fd, - IOCanReadHandler *fd_read_poll, - IOHandler *fd_read, - IOHandler *fd_write, - void *opaque); -int qemu_set_fd_handler(int fd, - IOHandler *fd_read, - IOHandler *fd_write, - void *opaque); #endif diff --git a/qemu-common.h b/qemu-common.h index fffdefdeca..5997f58540 100644 --- a/qemu-common.h +++ b/qemu-common.h @@ -13,7 +13,6 @@ typedef struct QEMUTimer QEMUTimer; typedef struct QEMUFile QEMUFile; -typedef struct QEMUBH QEMUBH; typedef struct DeviceState DeviceState; struct Monitor; @@ -117,23 +116,6 @@ extern int use_icount; int qemu_main(int argc, char **argv, char **envp); #endif -/* bottom halves */ -typedef void QEMUBHFunc(void *opaque); - -QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque); -void qemu_bh_schedule(QEMUBH *bh); -/* Bottom halfs that are scheduled from a bottom half handler are instantly - * invoked. This can create an infinite loop if a bottom half handler - * schedules itself. qemu_bh_schedule_idle() avoids this infinite loop by - * ensuring that the bottom half isn't executed until the next main loop - * iteration. - */ -void qemu_bh_schedule_idle(QEMUBH *bh); -void qemu_bh_cancel(QEMUBH *bh); -void qemu_bh_delete(QEMUBH *bh); -int qemu_bh_poll(void); -void qemu_bh_update_timeout(int *timeout); - void qemu_get_timedate(struct tm *tm, int offset); int qemu_timedate_diff(struct tm *tm); @@ -196,7 +178,6 @@ ssize_t qemu_write_full(int fd, const void *buf, size_t count) void qemu_set_cloexec(int fd); #ifndef _WIN32 -int qemu_add_child_watch(pid_t pid); int qemu_eventfd(int pipefd[2]); int qemu_pipe(int pipefd[2]); #endif @@ -211,14 +192,6 @@ int qemu_pipe(int pipefd[2]); void QEMU_NORETURN hw_error(const char *fmt, ...) GCC_FMT_ATTR(1, 2); -/* IO callbacks. */ -typedef void IOReadHandler(void *opaque, const uint8_t *buf, int size); -typedef int IOCanReadHandler(void *opaque); -typedef void IOHandler(void *opaque); - -void qemu_iohandler_fill(int *pnfds, fd_set *readfds, fd_set *writefds, fd_set *xfds); -void qemu_iohandler_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds, int rc); - struct ParallelIOArg { void *buffer; int count; @@ -280,9 +253,6 @@ void cpu_exec_init_all(void); void cpu_save(QEMUFile *f, void *opaque); int cpu_load(QEMUFile *f, void *opaque, int version_id); -/* Force QEMU to process pending events */ -void qemu_notify_event(void); - /* Unblock cpu */ void qemu_cpu_kick(void *env); void qemu_cpu_kick_self(void); diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c index 2a385a3bb8..6b58160058 100644 --- a/qemu-coroutine-lock.c +++ b/qemu-coroutine-lock.c @@ -26,6 +26,7 @@ #include "qemu-coroutine.h" #include "qemu-coroutine-int.h" #include "qemu-queue.h" +#include "main-loop.h" #include "trace.h" static QTAILQ_HEAD(, Coroutine) unlock_bh_queue = diff --git a/qemu-os-win32.h b/qemu-os-win32.h index 8a069d7fb6..5a9fd5dade 100644 --- a/qemu-os-win32.h +++ b/qemu-os-win32.h @@ -28,24 +28,11 @@ #include <windows.h> #include <winsock2.h> +#include "main-loop.h" /* Declaration of ffs() is missing in MinGW's strings.h. */ int ffs(int i); -/* Polling handling */ - -/* return TRUE if no sleep should be done afterwards */ -typedef int PollingFunc(void *opaque); - -int qemu_add_polling_cb(PollingFunc *func, void *opaque); -void qemu_del_polling_cb(PollingFunc *func, void *opaque); - -/* Wait objects handling */ -typedef void WaitObjectFunc(void *opaque); - -int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque); -void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque); - void os_host_main_loop_wait(int *timeout); static inline void os_setup_signal_handling(void) {} diff --git a/qemu-timer.h b/qemu-timer.h index 9f4ffed75c..67ca72e045 100644 --- a/qemu-timer.h +++ b/qemu-timer.h @@ -2,6 +2,7 @@ #define QEMU_TIMER_H #include "qemu-common.h" +#include "main-loop.h" #include "notify.h" #include <time.h> #include <sys/time.h> @@ -8,6 +8,7 @@ #include "qemu-timer.h" #include "qapi-types.h" #include "notify.h" +#include "main-loop.h" /* vl.c */ @@ -64,8 +65,6 @@ void do_info_snapshots(Monitor *mon); void qemu_announce_self(void); -int main_loop_wait(int nonblocking); - bool qemu_savevm_state_blocked(Monitor *mon); int qemu_savevm_state_begin(Monitor *mon, QEMUFile *f, int blk_enable, int shared); @@ -148,6 +148,7 @@ int main(int argc, char **argv) #include "qemu-objects.h" #include "qemu-options.h" #include "qmp-commands.h" +#include "main-loop.h" #ifdef CONFIG_VIRTFS #include "fsdev/qemu-fsdev.h" #endif |