qemu/qemu-common.h
aliguori 1b435b1032 Make bottom halves more robust
Bottom halves are supposed to not complete until the next iteration of the main
loop.  This is very important to ensure that guests can not cause stack
overflows in the block driver code.  Right now, if you attempt to schedule a
bottom half within a bottom half callback, you will enter an infinite loop.

This patch uses the same logic that we use for the IOHandler loop to make the
bottom half processing robust in list manipulation while in a callback.

This patch also introduces idle scheduling for bottom halves.  qemu_bh_poll()
returns an indication of whether any bottom halves were successfully executed.
qemu_aio_wait() uses this to immediately return if a bottom half was executed
instead of waiting for a completion notification.

qemu_bh_schedule_idle() works around this by not reporting the callback has
run in the qemu_bh_poll loop.  qemu_aio_wait() probably needs some refactoring
but that would require a larger code audit.  idle scheduling seems like a good
compromise.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>




git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5572 c046a42c-6fe2-441c-8c8c-71466251a162
2008-10-31 17:24:21 +00:00

148 lines
3.6 KiB
C

/* Common header file that is included by all of qemu. */
#ifndef QEMU_COMMON_H
#define QEMU_COMMON_H
/* we put basic includes here to avoid repeating them in device drivers */
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <inttypes.h>
#include <limits.h>
#include <time.h>
#include <ctype.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif
#ifndef O_BINARY
#define O_BINARY 0
#endif
#ifndef ENOMEDIUM
#define ENOMEDIUM ENODEV
#endif
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#define fsync _commit
#define lseek _lseeki64
#define ENOTSUP 4096
extern int qemu_ftruncate64(int, int64_t);
#define ftruncate qemu_ftruncate64
static inline char *realpath(const char *path, char *resolved_path)
{
_fullpath(resolved_path, path, _MAX_PATH);
return resolved_path;
}
#define PRId64 "I64d"
#define PRIx64 "I64x"
#define PRIu64 "I64u"
#define PRIo64 "I64o"
#endif
/* FIXME: Remove NEED_CPU_H. */
#ifndef NEED_CPU_H
#include "config-host.h"
#include <setjmp.h>
#include "osdep.h"
#include "bswap.h"
#else
#include "cpu.h"
#endif /* !defined(NEED_CPU_H) */
/* bottom halves */
typedef struct QEMUBH QEMUBH;
typedef void QEMUBHFunc(void *opaque);
QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque);
void qemu_bh_schedule(QEMUBH *bh);
void qemu_bh_schedule_idle(QEMUBH *bh);
void qemu_bh_cancel(QEMUBH *bh);
void qemu_bh_delete(QEMUBH *bh);
int qemu_bh_poll(void);
uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c);
void qemu_get_timedate(struct tm *tm, int offset);
int qemu_timedate_diff(struct tm *tm);
/* cutils.c */
void pstrcpy(char *buf, int buf_size, const char *str);
char *pstrcat(char *buf, int buf_size, const char *s);
char *pstrdup(const char *str, size_t buf_size);
int strstart(const char *str, const char *val, const char **ptr);
int stristart(const char *str, const char *val, const char **ptr);
time_t mktimegm(struct tm *tm);
void *qemu_malloc(size_t size);
void *qemu_realloc(void *ptr, size_t size);
void *qemu_mallocz(size_t size);
void qemu_free(void *ptr);
char *qemu_strdup(const char *str);
void *get_mmap_addr(unsigned long size);
/* Error handling. */
void hw_error(const char *fmt, ...)
__attribute__ ((__format__ (__printf__, 1, 2)))
__attribute__ ((__noreturn__));
/* IO callbacks. */
typedef void IOReadHandler(void *opaque, const uint8_t *buf, int size);
typedef int IOCanRWHandler(void *opaque);
typedef void IOHandler(void *opaque);
struct ParallelIOArg {
void *buffer;
int count;
};
typedef int (*DMA_transfer_handler) (void *opaque, int nchan, int pos, int size);
/* A load of opaque types so that device init declarations don't have to
pull in all the real definitions. */
typedef struct NICInfo NICInfo;
typedef struct HCIInfo HCIInfo;
typedef struct AudioState AudioState;
typedef struct BlockDriverState BlockDriverState;
typedef struct DisplayState DisplayState;
typedef struct TextConsole TextConsole;
typedef TextConsole QEMUConsole;
typedef struct CharDriverState CharDriverState;
typedef struct VLANState VLANState;
typedef struct QEMUFile QEMUFile;
typedef struct i2c_bus i2c_bus;
typedef struct i2c_slave i2c_slave;
typedef struct SMBusDevice SMBusDevice;
typedef struct QEMUTimer QEMUTimer;
typedef struct PCIBus PCIBus;
typedef struct PCIDevice PCIDevice;
typedef struct SerialState SerialState;
typedef struct IRQState *qemu_irq;
struct pcmcia_card_s;
/* CPU save/load. */
void cpu_save(QEMUFile *f, void *opaque);
int cpu_load(QEMUFile *f, void *opaque, int version_id);
/* Force QEMU to stop what it's doing and service IO */
void qemu_service_io(void);
#endif