vl.c

qemu性能直逼VMware的仿真器QEMU 的模擬速度約為實機的 25％；約為 Bochs 的 60 倍。Plex86、User-Mode-Linux、VMware 和 Virtual PC 則比

        itv.it_interval.tv_sec = 0;
        itv.it_interval.tv_usec = 999; /* for i386 kernel 2.6 to get 1 ms */
        itv.it_value.tv_sec = 0;
        itv.it_value.tv_usec = 10 * 1000;
        setitimer(ITIMER_REAL, &itv, NULL);
        /* we probe the tick duration of the kernel to inform the user if
           the emulated kernel requested a too high timer frequency */
        getitimer(ITIMER_REAL, &itv);

#if defined(__linux__)
        /* XXX: force /dev/rtc usage because even 2.6 kernels may not
           have timers with 1 ms resolution. The correct solution will
           be to use the POSIX real time timers available in recent
           2.6 kernels */
        if (itv.it_interval.tv_usec > 1000 || 1) {
            /* try to use /dev/rtc to have a faster timer */
            if (start_rtc_timer() < 0)
                goto use_itimer;
            /* disable itimer */
            itv.it_interval.tv_sec = 0;
            itv.it_interval.tv_usec = 0;
            itv.it_value.tv_sec = 0;
            itv.it_value.tv_usec = 0;
            setitimer(ITIMER_REAL, &itv, NULL);

            /* use the RTC */
            sigaction(SIGIO, &act, NULL);
            fcntl(rtc_fd, F_SETFL, O_ASYNC);
            fcntl(rtc_fd, F_SETOWN, getpid());
        } else 
#endif /* defined(__linux__) */
        {
        use_itimer:
            pit_min_timer_count = ((uint64_t)itv.it_interval.tv_usec * 
                                   PIT_FREQ) / 1000000;
        }
    }
#endif
}

void quit_timers(void)
{
#ifdef _WIN32
    timeKillEvent(timerID);
    timeEndPeriod(period);
    if (host_alarm) {
        CloseHandle(host_alarm);
        host_alarm = NULL;
    }
#endif
}

/***********************************************************/
/* character device */

static void qemu_chr_event(CharDriverState *s, int event)
{
    if (!s->chr_event)
        return;
    s->chr_event(s->handler_opaque, event);
}

static void qemu_chr_reset_bh(void *opaque)
{
    CharDriverState *s = opaque;
    qemu_chr_event(s, CHR_EVENT_RESET);
    qemu_bh_delete(s->bh);
    s->bh = NULL;
}

void qemu_chr_reset(CharDriverState *s)
{
    if (s->bh == NULL) {
	s->bh = qemu_bh_new(qemu_chr_reset_bh, s);
	qemu_bh_schedule(s->bh);
    }
}

int qemu_chr_write(CharDriverState *s, const uint8_t *buf, int len)
{
    return s->chr_write(s, buf, len);
}

int qemu_chr_ioctl(CharDriverState *s, int cmd, void *arg)
{
    if (!s->chr_ioctl)
        return -ENOTSUP;
    return s->chr_ioctl(s, cmd, arg);
}

int qemu_chr_can_read(CharDriverState *s)
{
    if (!s->chr_can_read)
        return 0;
    return s->chr_can_read(s->handler_opaque);
}

void qemu_chr_read(CharDriverState *s, uint8_t *buf, int len)
{
    s->chr_read(s->handler_opaque, buf, len);
}


void qemu_chr_printf(CharDriverState *s, const char *fmt, ...)
{
    char buf[4096];
    va_list ap;
    va_start(ap, fmt);
    vsnprintf(buf, sizeof(buf), fmt, ap);
    qemu_chr_write(s, buf, strlen(buf));
    va_end(ap);
}

void qemu_chr_send_event(CharDriverState *s, int event)
{
    if (s->chr_send_event)
        s->chr_send_event(s, event);
}

void qemu_chr_add_handlers(CharDriverState *s, 
                           IOCanRWHandler *fd_can_read, 
                           IOReadHandler *fd_read,
                           IOEventHandler *fd_event,
                           void *opaque)
{
    s->chr_can_read = fd_can_read;
    s->chr_read = fd_read;
    s->chr_event = fd_event;
    s->handler_opaque = opaque;
    if (s->chr_update_read_handler)
        s->chr_update_read_handler(s);
}
             
static int null_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    return len;
}

static CharDriverState *qemu_chr_open_null(void)
{
    CharDriverState *chr;

    chr = qemu_mallocz(sizeof(CharDriverState));
    if (!chr)
        return NULL;
    chr->chr_write = null_chr_write;
    return chr;
}

#ifdef _WIN32

static void socket_cleanup(void)
{
    WSACleanup();
}

static int socket_init(void)
{
    WSADATA Data;
    int ret, err;

    ret = WSAStartup(MAKEWORD(2,2), &Data);
    if (ret != 0) {
        err = WSAGetLastError();
        fprintf(stderr, "WSAStartup: %d\n", err);
        return -1;
    }
    atexit(socket_cleanup);
    return 0;
}

static int send_all(int fd, const uint8_t *buf, int len1)
{
    int ret, len;
    
    len = len1;
    while (len > 0) {
        ret = send(fd, buf, len, 0);
        if (ret < 0) {
            int errno;
            errno = WSAGetLastError();
            if (errno != WSAEWOULDBLOCK) {
                return -1;
            }
        } else if (ret == 0) {
            break;
        } else {
            buf += ret;
            len -= ret;
        }
    }
    return len1 - len;
}

void socket_set_nonblock(int fd)
{
    unsigned long opt = 1;
    ioctlsocket(fd, FIONBIO, &opt);
}

#else

static int unix_write(int fd, const uint8_t *buf, int len1)
{
    int ret, len;

    len = len1;
    while (len > 0) {
        ret = write(fd, buf, len);
        if (ret < 0) {
            if (errno != EINTR && errno != EAGAIN)
                return -1;
        } else if (ret == 0) {
            break;
        } else {
            buf += ret;
            len -= ret;
        }
    }
    return len1 - len;
}

static inline int send_all(int fd, const uint8_t *buf, int len1)
{
    return unix_write(fd, buf, len1);
}

void socket_set_nonblock(int fd)
{
    fcntl(fd, F_SETFL, O_NONBLOCK);
}
#endif /* !_WIN32 */

#ifndef _WIN32

typedef struct {
    int fd_in, fd_out;
    int max_size;
} FDCharDriver;

#define STDIO_MAX_CLIENTS 2

static int stdio_nb_clients;
static CharDriverState *stdio_clients[STDIO_MAX_CLIENTS];

static int fd_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    FDCharDriver *s = chr->opaque;
    return unix_write(s->fd_out, buf, len);
}

static int fd_chr_read_poll(void *opaque)
{
    CharDriverState *chr = opaque;
    FDCharDriver *s = chr->opaque;

    s->max_size = qemu_chr_can_read(chr);
    return s->max_size;
}

static void fd_chr_read(void *opaque)
{
    CharDriverState *chr = opaque;
    FDCharDriver *s = chr->opaque;
    int size, len;
    uint8_t buf[1024];
    
    len = sizeof(buf);
    if (len > s->max_size)
        len = s->max_size;
    if (len == 0)
        return;
    size = read(s->fd_in, buf, len);
    if (size == 0) {
        /* FD has been closed. Remove it from the active list.  */
        qemu_set_fd_handler2(s->fd_in, NULL, NULL, NULL, NULL);
        return;
    }
    if (size > 0) {
        qemu_chr_read(chr, buf, size);
    }
}

static void fd_chr_update_read_handler(CharDriverState *chr)
{
    FDCharDriver *s = chr->opaque;

    if (s->fd_in >= 0) {
        if (nographic && s->fd_in == 0) {
        } else {
            qemu_set_fd_handler2(s->fd_in, fd_chr_read_poll, 
                                 fd_chr_read, NULL, chr);
        }
    }
}

/* open a character device to a unix fd */
static CharDriverState *qemu_chr_open_fd(int fd_in, int fd_out)
{
    CharDriverState *chr;
    FDCharDriver *s;

    chr = qemu_mallocz(sizeof(CharDriverState));
    if (!chr)
        return NULL;
    s = qemu_mallocz(sizeof(FDCharDriver));
    if (!s) {
        free(chr);
        return NULL;
    }
    s->fd_in = fd_in;
    s->fd_out = fd_out;
    chr->opaque = s;
    chr->chr_write = fd_chr_write;
    chr->chr_update_read_handler = fd_chr_update_read_handler;

    qemu_chr_reset(chr);

    return chr;
}

static CharDriverState *qemu_chr_open_file_out(const char *file_out)
{
    int fd_out;

    fd_out = open(file_out, O_WRONLY | O_TRUNC | O_CREAT | O_BINARY, 0666);
    if (fd_out < 0)
        return NULL;
    return qemu_chr_open_fd(-1, fd_out);
}

static CharDriverState *qemu_chr_open_pipe(const char *filename)
{
    int fd_in, fd_out;
    char filename_in[256], filename_out[256];

    snprintf(filename_in, 256, "%s.in", filename);
    snprintf(filename_out, 256, "%s.out", filename);
    fd_in = open(filename_in, O_RDWR | O_BINARY);
    fd_out = open(filename_out, O_RDWR | O_BINARY);
    if (fd_in < 0 || fd_out < 0) {
	if (fd_in >= 0)
	    close(fd_in);
	if (fd_out >= 0)
	    close(fd_out);
        fd_in = fd_out = open(filename, O_RDWR | O_BINARY);
        if (fd_in < 0)
            return NULL;
    }
    return qemu_chr_open_fd(fd_in, fd_out);
}


/* for STDIO, we handle the case where several clients use it
   (nographic mode) */

#define TERM_ESCAPE 0x01 /* ctrl-a is used for escape */

#define TERM_FIFO_MAX_SIZE 1

static int term_got_escape, client_index;
static uint8_t term_fifo[TERM_FIFO_MAX_SIZE];
static int term_fifo_size;
static int term_timestamps;
static int64_t term_timestamps_start;

void term_print_help(void)
{
    printf("\n"
           "C-a h    print this help\n"
           "C-a x    exit emulator\n"
           "C-a s    save disk data back to file (if -snapshot)\n"
           "C-a b    send break (magic sysrq)\n"
           "C-a t    toggle console timestamps\n"
           "C-a c    switch between console and monitor\n"
           "C-a C-a  send C-a\n"
           );
}

/* called when a char is received */
static void stdio_received_byte(int ch)
{
    if (term_got_escape) {
        term_got_escape = 0;
        switch(ch) {
        case 'h':
            term_print_help();
            break;
        case 'x':
            exit(0);
            break;
        case 's': 
            {
                int i;
                for (i = 0; i < MAX_DISKS; i++) {
                    if (bs_table[i])
                        bdrv_commit(bs_table[i]);
                }
            }
            break;
        case 'b':
            if (client_index < stdio_nb_clients) {
                CharDriverState *chr;
                FDCharDriver *s;

                chr = stdio_clients[client_index];
                s = chr->opaque;
                qemu_chr_event(chr, CHR_EVENT_BREAK);
            }
            break;
        case 'c':
            client_index++;
            if (client_index >= stdio_nb_clients)
                client_index = 0;
            if (client_index == 0) {
                /* send a new line in the monitor to get the prompt */
                ch = '\r';
                goto send_char;
            }
            break;
        case 't':
            term_timestamps = !term_timestamps;
            term_timestamps_start = -1;
            break;
        case TERM_ESCAPE:
            goto send_char;
        }
    } else if (ch == TERM_ESCAPE) {
        term_got_escape = 1;
    } else {
    send_char:
        if (client_index < stdio_nb_clients) {
            uint8_t buf[1];
            CharDriverState *chr;
            
            chr = stdio_clients[client_index];
            if (qemu_chr_can_read(chr) > 0) {
                buf[0] = ch;
                qemu_chr_read(chr, buf, 1);
            } else if (term_fifo_size == 0) {
                term_fifo[term_fifo_size++] = ch;
            }
        }
    }
}

static int stdio_read_poll(void *opaque)
{
    CharDriverState *chr;

    if (client_index < stdio_nb_clients) {
        chr = stdio_clients[client_index];
        /* try to flush the queue if needed */
        if (term_fifo_size != 0 && qemu_chr_can_read(chr) > 0) {
            qemu_chr_read(chr, term_fifo, 1);
            term_fifo_size = 0;
        }
        /* see if we can absorb more chars */
        if (term_fifo_size == 0)
            return 1;
        else
            return 0;
    } else {
        return 1;
    }
}

static void stdio_read(void *opaque)
{
    int size;
    uint8_t buf[1];
    
    size = read(0, buf, 1);
    if (size == 0) {
        /* stdin has been closed. Remove it from the active list.  */
        qemu_set_fd_handler2(0, NULL, NULL, NULL, NULL);
        return;
    }
    if (size > 0)
        stdio_received_byte(buf[0]);
}

static int stdio_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    FDCharDriver *s = chr->opaque;
    if (!term_timestamps) {
        return unix_write(s->fd_out, buf, len);
    } else {
        int i;
        char buf1[64];

        for(i = 0; i < len; i++) {
            unix_write(s->fd_out, buf + i, 1);
            if (buf[i] == '\n') {
                int64_t ti;
                int secs;

                ti = get_clock();
                if (term_timestamps_start == -1)
                    term_timestamps_start = ti;
                ti -= term_timestamps_start;
                secs = ti / 1000000000;
                snprintf(buf1, sizeof(buf1), 
                         "[%02d:%02d:%02d.%03d] ",
                         secs / 3600,
                         (secs / 60) % 60,
                         secs % 60,
                         (int)((ti / 1000000) % 1000));
                unix_write(s->fd_out, buf1, strlen(buf1));
            }
        }
        return len;
    }
}

/* init terminal so that we can grab keys */
static struct termios oldtty;
static int old_fd0_flags;

static void term_exit(void)
{
    tcsetattr (0, TCSANOW, &oldtty);
    fcntl(0, F_SETFL, old_fd0_flags);
}

static void term_init(void)
{
    struct termios tty;

    tcgetattr (0, &tty);
    oldtty = tty;
    old_fd0_flags = fcntl(0, F_GETFL);