Archipelago » qemu

/*

 * QEMU System Emulator

 * 

 * Copyright (c) 2003-2004 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 <stdlib.h>

#include <stdio.h>

#include <stdarg.h>

#include <string.h>

#include <ctype.h>

#include <getopt.h>

#include <inttypes.h>

#include <unistd.h>

#include <sys/mman.h>

#include <fcntl.h>

#include <signal.h>

#include <time.h>

#include <sys/time.h>

#include <malloc.h>

#include <termios.h>

#include <sys/poll.h>

#include <errno.h>

#include <sys/wait.h>

#include <sys/ioctl.h>

#include <sys/socket.h>

#include <linux/if.h>

#include <linux/if_tun.h>

#include "disas.h"

#include "thunk.h"

#include "vl.h"

#define DEFAULT_NETWORK_SCRIPT "/etc/qemu-ifup"

//#define DEBUG_UNUSED_IOPORT

#if !defined(CONFIG_SOFTMMU)

#define PHYS_RAM_MAX_SIZE (256 * 1024 * 1024)

#else

#define PHYS_RAM_MAX_SIZE (2047 * 1024 * 1024)

#endif

#if defined (TARGET_I386)

#elif defined (TARGET_PPC)

//#define USE_OPEN_FIRMWARE

#if !defined (USE_OPEN_FIRMWARE)

#define KERNEL_LOAD_ADDR    0x01000000

#define KERNEL_STACK_ADDR   0x01200000

#else

#define KERNEL_LOAD_ADDR    0x00000000

#define KERNEL_STACK_ADDR   0x00400000

#endif

#endif

#define GUI_REFRESH_INTERVAL 30 

/* XXX: use a two level table to limit memory usage */

#define MAX_IOPORTS 65536

const char *bios_dir = CONFIG_QEMU_SHAREDIR;

char phys_ram_file[1024];

CPUState *global_env;

CPUState *cpu_single_env;

IOPortReadFunc *ioport_read_table[3][MAX_IOPORTS];

IOPortWriteFunc *ioport_write_table[3][MAX_IOPORTS];

BlockDriverState *bs_table[MAX_DISKS], *fd_table[MAX_FD];

int vga_ram_size;

static DisplayState display_state;

int nographic;

int term_inited;

int64_t ticks_per_sec;

int boot_device = 'c';

static int ram_size;

static char network_script[1024];

int pit_min_timer_count = 0;

/***********************************************************/

/* x86 io ports */

uint32_t default_ioport_readb(CPUState *env, uint32_t address)

{

#ifdef DEBUG_UNUSED_IOPORT

    fprintf(stderr, "inb: port=0x%04x\n", address);

#endif

    return 0xff;

}

void default_ioport_writeb(CPUState *env, uint32_t address, uint32_t data)

{

#ifdef DEBUG_UNUSED_IOPORT

    fprintf(stderr, "outb: port=0x%04x data=0x%02x\n", address, data);

#endif

}

/* default is to make two byte accesses */

uint32_t default_ioport_readw(CPUState *env, uint32_t address)

{

    uint32_t data;

    data = ioport_read_table[0][address & (MAX_IOPORTS - 1)](env, address);

    data |= ioport_read_table[0][(address + 1) & (MAX_IOPORTS - 1)](env, address + 1) << 8;

    return data;

}

void default_ioport_writew(CPUState *env, uint32_t address, uint32_t data)

{

    ioport_write_table[0][address & (MAX_IOPORTS - 1)](env, address, data & 0xff);

    ioport_write_table[0][(address + 1) & (MAX_IOPORTS - 1)](env, address + 1, (data >> 8) & 0xff);

}

uint32_t default_ioport_readl(CPUState *env, uint32_t address)

{

#ifdef DEBUG_UNUSED_IOPORT

    fprintf(stderr, "inl: port=0x%04x\n", address);

#endif

    return 0xffffffff;

}

void default_ioport_writel(CPUState *env, uint32_t address, uint32_t data)

{

#ifdef DEBUG_UNUSED_IOPORT

    fprintf(stderr, "outl: port=0x%04x data=0x%02x\n", address, data);

#endif

}

void init_ioports(void)

{

    int i;

    for(i = 0; i < MAX_IOPORTS; i++) {

        ioport_read_table[0][i] = default_ioport_readb;

        ioport_write_table[0][i] = default_ioport_writeb;

        ioport_read_table[1][i] = default_ioport_readw;

        ioport_write_table[1][i] = default_ioport_writew;

        ioport_read_table[2][i] = default_ioport_readl;

        ioport_write_table[2][i] = default_ioport_writel;

    }

}

/* size is the word size in byte */

int register_ioport_read(int start, int length, IOPortReadFunc *func, int size)

{

    int i, bsize;

    if (size == 1)

        bsize = 0;

    else if (size == 2)

        bsize = 1;

    else if (size == 4)

        bsize = 2;

    else

        return -1;

    for(i = start; i < start + length; i += size)

        ioport_read_table[bsize][i] = func;

    return 0;

}

/* size is the word size in byte */

int register_ioport_write(int start, int length, IOPortWriteFunc *func, int size)

{

    int i, bsize;

    if (size == 1)

        bsize = 0;

    else if (size == 2)

        bsize = 1;

    else if (size == 4)

        bsize = 2;

    else

        return -1;

    for(i = start; i < start + length; i += size)

        ioport_write_table[bsize][i] = func;

    return 0;

}

void pstrcpy(char *buf, int buf_size, const char *str)

{

    int c;

    char *q = buf;

    if (buf_size <= 0)

        return;

    for(;;) {

        c = *str++;

        if (c == 0 || q >= buf + buf_size - 1)

            break;

        *q++ = c;

    }

    *q = '\0';

}

/* strcat and truncate. */

char *pstrcat(char *buf, int buf_size, const char *s)

{

    int len;

    len = strlen(buf);

    if (len < buf_size) 

        pstrcpy(buf + len, buf_size - len, s);

    return buf;

}

/* return the size or -1 if error */

int load_image(const char *filename, uint8_t *addr)

{

    int fd, size;

    fd = open(filename, O_RDONLY);

    if (fd < 0)

        return -1;

    size = lseek(fd, 0, SEEK_END);

    lseek(fd, 0, SEEK_SET);

    if (read(fd, addr, size) != size) {

        close(fd);

        return -1;

    }

    close(fd);

    return size;

}

void cpu_outb(CPUState *env, int addr, int val)

{

    ioport_write_table[0][addr & (MAX_IOPORTS - 1)](env, addr, val);

}

void cpu_outw(CPUState *env, int addr, int val)

{

    ioport_write_table[1][addr & (MAX_IOPORTS - 1)](env, addr, val);

}

void cpu_outl(CPUState *env, int addr, int val)

{

    ioport_write_table[2][addr & (MAX_IOPORTS - 1)](env, addr, val);

}

int cpu_inb(CPUState *env, int addr)

{

    return ioport_read_table[0][addr & (MAX_IOPORTS - 1)](env, addr);

}

int cpu_inw(CPUState *env, int addr)

{

    return ioport_read_table[1][addr & (MAX_IOPORTS - 1)](env, addr);

}

int cpu_inl(CPUState *env, int addr)

{

    return ioport_read_table[2][addr & (MAX_IOPORTS - 1)](env, addr);

}

/***********************************************************/

void hw_error(const char *fmt, ...)

{

    va_list ap;

    va_start(ap, fmt);

    fprintf(stderr, "qemu: hardware error: ");

    vfprintf(stderr, fmt, ap);

    fprintf(stderr, "\n");

#ifdef TARGET_I386

    cpu_x86_dump_state(global_env, stderr, X86_DUMP_FPU | X86_DUMP_CCOP);

#else

    cpu_dump_state(global_env, stderr, 0);

#endif

    va_end(ap);

    abort();

}

#if defined(__powerpc__)

static inline uint32_t get_tbl(void) 

{

    uint32_t tbl;

    asm volatile("mftb %0" : "=r" (tbl));

    return tbl;

}

static inline uint32_t get_tbu(void) 

{

        uint32_t tbl;

        asm volatile("mftbu %0" : "=r" (tbl));

        return tbl;

}

int64_t cpu_get_real_ticks(void)

{

    uint32_t l, h, h1;

    /* NOTE: we test if wrapping has occurred */

    do {

        h = get_tbu();

        l = get_tbl();

        h1 = get_tbu();

    } while (h != h1);

    return ((int64_t)h << 32) | l;

}

#elif defined(__i386__)

int64_t cpu_get_real_ticks(void)

{

    int64_t val;

    asm("rdtsc" : "=A" (val));

    return val;

}

#else

#error unsupported CPU

#endif

static int64_t cpu_ticks_offset;

static int64_t cpu_ticks_last;

int64_t cpu_get_ticks(void)

{

    return cpu_get_real_ticks() + cpu_ticks_offset;

}

/* enable cpu_get_ticks() */

void cpu_enable_ticks(void)

{

    cpu_ticks_offset = cpu_ticks_last - cpu_get_real_ticks();

}

/* disable cpu_get_ticks() : the clock is stopped. You must not call

   cpu_get_ticks() after that.  */

void cpu_disable_ticks(void)

{

    cpu_ticks_last = cpu_get_ticks();

}

int64_t get_clock(void)

{

    struct timeval tv;

    gettimeofday(&tv, NULL);

    return tv.tv_sec * 1000000LL + tv.tv_usec;

}

void cpu_calibrate_ticks(void)

{

    int64_t usec, ticks;

    usec = get_clock();

    ticks = cpu_get_ticks();

    usleep(50 * 1000);

    usec = get_clock() - usec;

    ticks = cpu_get_ticks() - ticks;

    ticks_per_sec = (ticks * 1000000LL + (usec >> 1)) / usec;

}

/* compute with 96 bit intermediate result: (a*b)/c */

uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)

{

    union {

        uint64_t ll;

        struct {

#ifdef WORDS_BIGENDIAN

            uint32_t high, low;

#else

            uint32_t low, high;

#endif            

        } l;

    } u, res;

    uint64_t rl, rh;

    u.ll = a;

    rl = (uint64_t)u.l.low * (uint64_t)b;

    rh = (uint64_t)u.l.high * (uint64_t)b;

    rh += (rl >> 32);

    res.l.high = rh / c;

    res.l.low = (((rh % c) << 32) + (rl & 0xffffffff)) / c;

    return res.ll;

}

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

static int term_got_escape, term_command;

static unsigned char term_cmd_buf[128];

typedef struct term_cmd_t {

    const unsigned char *name;

    void (*handler)(unsigned char *params);

} term_cmd_t;

static void do_change_cdrom (unsigned char *params);

static void do_change_fd0 (unsigned char *params);

static void do_change_fd1 (unsigned char *params);

static term_cmd_t term_cmds[] = {

    { "changecd", &do_change_cdrom, },

    { "changefd0", &do_change_fd0, },

    { "changefd1", &do_change_fd1, },

    { NULL, NULL, },

};

void term_print_help(void)

{

    printf("\n"

           "C-a h    print this help\n"

           "C-a x    exit emulatior\n"

           "C-a d    switch on/off debug log\n"

           "C-a s    save disk data back to file (if -snapshot)\n"

           "C-a b    send break (magic sysrq)\n"

           "C-a c    send qemu internal command\n"

           "C-a C-a  send C-a\n"

           );

}

static void do_change_cdrom (unsigned char *params)

{

    /* Dunno how to do it... */

}

static void do_change_fd (int fd, unsigned char *params)

{

    unsigned char *name_start, *name_end, *ros;

    int ro;

    for (name_start = params;

         isspace(*name_start); name_start++)

        continue;

    if (*name_start == '\0')

        return;

    for (name_end = name_start;

         !isspace(*name_end) && *name_end != '\0'; name_end++)

        continue;

    for (ros = name_end + 1; isspace(*ros); ros++)

        continue;

    if (ros[0] == 'r' && ros[1] == 'o')

        ro = 1;

    else

        ro = 0;

    *name_end = '\0';

    printf("Change fd %d to %s (%s)\n", fd, name_start, params);

    fdctrl_disk_change(fd, name_start, ro);

}

static void do_change_fd0 (unsigned char *params)

{

    do_change_fd(0, params);

}

static void do_change_fd1 (unsigned char *params)

{

    do_change_fd(1, params);

}

static void term_treat_command(void)

{

    unsigned char *cmd_start, *cmd_end;

    int i;

    for (cmd_start = term_cmd_buf; isspace(*cmd_start); cmd_start++)

        continue;

    for (cmd_end = cmd_start;

         !isspace(*cmd_end) && *cmd_end != '\0'; cmd_end++)

        continue;

    for (i = 0; term_cmds[i].name != NULL; i++) {

        if (strlen(term_cmds[i].name) == (cmd_end - cmd_start) &&

            memcmp(term_cmds[i].name, cmd_start, cmd_end - cmd_start) == 0) {

            (*term_cmds[i].handler)(cmd_end + 1);

            return;

        }

    }

    *cmd_end = '\0';

    printf("Unknown term command: %s\n", cmd_start);

}

extern FILE *logfile;

/* called when a char is received */

void term_received_byte(int ch)

{

    if (term_command) {

        if (ch == '\n' || ch == '\r' || term_command == 127) {

            printf("\n");

            term_treat_command();

            term_command = 0;

        } else {

            if (ch == 0x7F || ch == 0x08) {

                if (term_command > 1) {

                    term_cmd_buf[--term_command - 1] = '\0';

                    printf("\r                                               "

                           "                               ");

                    printf("\r> %s", term_cmd_buf);

                }

            } else if (ch > 0x1f) {

                term_cmd_buf[term_command++ - 1] = ch;

                term_cmd_buf[term_command - 1] = '\0';

                printf("\r> %s", term_cmd_buf);

            }

            fflush(stdout);

        }

    } else 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':

            serial_receive_break();

            break;

        case 'c':

            printf("> ");

            fflush(stdout);

            term_command = 1;

            break;

        case 'd':

            cpu_set_log(CPU_LOG_ALL);

            break;

        case TERM_ESCAPE:

            goto send_char;

        }

    } else if (ch == TERM_ESCAPE) {

        term_got_escape = 1;

    } else {

    send_char:

        serial_receive_byte(ch);

    }

}

/***********************************************************/

/* Linux network device redirector */

int net_init(void)

{

    struct ifreq ifr;

    int fd, ret, pid, status;

    fd = open("/dev/net/tun", O_RDWR);

    if (fd < 0) {

        fprintf(stderr, "warning: could not open /dev/net/tun: no virtual network emulation\n");

        return -1;

    }

    memset(&ifr, 0, sizeof(ifr));

    ifr.ifr_flags = IFF_TAP | IFF_NO_PI;

    pstrcpy(ifr.ifr_name, IFNAMSIZ, "tun%d");

    ret = ioctl(fd, TUNSETIFF, (void *) &ifr);

    if (ret != 0) {

        fprintf(stderr, "warning: could not configure /dev/net/tun: no virtual network emulation\n");

        close(fd);

        return -1;

    }

    printf("Connected to host network interface: %s\n", ifr.ifr_name);

    fcntl(fd, F_SETFL, O_NONBLOCK);

    net_fd = fd;

    /* try to launch network init script */

    pid = fork();

    if (pid >= 0) {

        if (pid == 0) {

            execl(network_script, network_script, ifr.ifr_name, NULL);

            exit(1);

        }

        while (waitpid(pid, &status, 0) != pid);

        if (!WIFEXITED(status) ||

            WEXITSTATUS(status) != 0) {

            fprintf(stderr, "%s: could not launch network script for '%s'\n",

                    network_script, ifr.ifr_name);

        }

    }

    return 0;

}

void net_send_packet(int net_fd, const uint8_t *buf, int size)

{

#ifdef DEBUG_NE2000

    printf("NE2000: sending packet size=%d\n", size);

#endif

    write(net_fd, buf, size);

}

/***********************************************************/

/* dumb display */

/* init terminal so that we can grab keys */

static struct termios oldtty;

static void term_exit(void)

{

    tcsetattr (0, TCSANOW, &oldtty);

}

static void term_init(void)

{

    struct termios tty;

    tcgetattr (0, &tty);

    oldtty = tty;

    tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP

                          |INLCR|IGNCR|ICRNL|IXON);

    tty.c_oflag |= OPOST;

    tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);

    /* if graphical mode, we allow Ctrl-C handling */

    if (nographic)

        tty.c_lflag &= ~ISIG;

    tty.c_cflag &= ~(CSIZE|PARENB);

    tty.c_cflag |= CS8;

    tty.c_cc[VMIN] = 1;

    tty.c_cc[VTIME] = 0;

    tcsetattr (0, TCSANOW, &tty);

    atexit(term_exit);

    fcntl(0, F_SETFL, O_NONBLOCK);

}

static void dumb_update(DisplayState *ds, int x, int y, int w, int h)

{

}

static void dumb_resize(DisplayState *ds, int w, int h)

{

}

static void dumb_refresh(DisplayState *ds)

{

    vga_update_display();

}

void dumb_display_init(DisplayState *ds)

{

    ds->data = NULL;

    ds->linesize = 0;

    ds->depth = 0;

    ds->dpy_update = dumb_update;

    ds->dpy_resize = dumb_resize;

    ds->dpy_refresh = dumb_refresh;

}

#if !defined(CONFIG_SOFTMMU)

/***********************************************************/

/* cpu signal handler */

static void host_segv_handler(int host_signum, siginfo_t *info, 

                              void *puc)

{

    if (cpu_signal_handler(host_signum, info, puc))

        return;

    term_exit();

    abort();

}

#endif

static int timer_irq_pending;

static int timer_irq_count;

static int timer_ms;

static int gui_refresh_pending, gui_refresh_count;

static void host_alarm_handler(int host_signum, siginfo_t *info, 

                               void *puc)

{

    /* NOTE: since usually the OS asks a 100 Hz clock, there can be

       some drift between cpu_get_ticks() and the interrupt time. So

       we queue some interrupts to avoid missing some */

    timer_irq_count += pit_get_out_edges(&pit_channels[0]);

    if (timer_irq_count) {

        if (timer_irq_count > 2)

            timer_irq_count = 2;

        timer_irq_count--;

        timer_irq_pending = 1;

    }

    gui_refresh_count += timer_ms;

    if (gui_refresh_count >= GUI_REFRESH_INTERVAL) {

        gui_refresh_count = 0;

        gui_refresh_pending = 1;

    }

    if (gui_refresh_pending || timer_irq_pending) {

        /* just exit from the cpu to have a chance to handle timers */

        cpu_interrupt(global_env, CPU_INTERRUPT_EXIT);

    }

}

/* main execution loop */

CPUState *cpu_gdbstub_get_env(void *opaque)

{

    return global_env;

}

int main_loop(void *opaque)

{

    struct pollfd ufds[3], *pf, *serial_ufd, *gdb_ufd;

#if defined (TARGET_I386)

    struct pollfd *net_ufd;

#endif

    int ret, n, timeout, serial_ok;

    uint8_t ch;

    CPUState *env = global_env;

    if (!term_inited) {

        /* initialize terminal only there so that the user has a

           chance to stop QEMU with Ctrl-C before the gdb connection

           is launched */

        term_inited = 1;

        term_init();

    }

    serial_ok = 1;

    cpu_enable_ticks();

    for(;;) {

#if defined (DO_TB_FLUSH)

        tb_flush();

#endif

        ret = cpu_exec(env);

        if (reset_requested) {

            ret = EXCP_INTERRUPT; 

            break;

        }

        if (ret == EXCP_DEBUG) {

            ret = EXCP_DEBUG;

            break;

        }

        /* if hlt instruction, we wait until the next IRQ */

        if (ret == EXCP_HLT) 

            timeout = 10;

        else

            timeout = 0;

        /* poll any events */

        serial_ufd = NULL;

        pf = ufds;

        if (serial_ok && serial_can_receive()) {

            serial_ufd = pf;

            pf->fd = 0;

            pf->events = POLLIN;

            pf++;

        }

#if defined (TARGET_I386)

        net_ufd = NULL;

        if (net_fd > 0 && ne2000_can_receive()) {

            net_ufd = pf;

            pf->fd = net_fd;

            pf->events = POLLIN;

            pf++;

        }

#endif

        gdb_ufd = NULL;

        if (gdbstub_fd > 0) {

            gdb_ufd = pf;

            pf->fd = gdbstub_fd;

            pf->events = POLLIN;

            pf++;

        }

        ret = poll(ufds, pf - ufds, timeout);

        if (ret > 0) {

            if (serial_ufd && (serial_ufd->revents & POLLIN)) {

                n = read(0, &ch, 1);

                if (n == 1) {

                    term_received_byte(ch);

                } else {

                    /* Closed, stop polling. */

                    serial_ok = 0;

                }

            }

#if defined (TARGET_I386)

            if (net_ufd && (net_ufd->revents & POLLIN)) {

                uint8_t buf[MAX_ETH_FRAME_SIZE];

                n = read(net_fd, buf, MAX_ETH_FRAME_SIZE);

                if (n > 0) {

                    if (n < 60) {

                        memset(buf + n, 0, 60 - n);

                        n = 60;

                    }

                    ne2000_receive(buf, n);

                }

            }

#endif

            if (gdb_ufd && (gdb_ufd->revents & POLLIN)) {

                uint8_t buf[1];

                /* stop emulation if requested by gdb */

                n = read(gdbstub_fd, buf, 1);

                if (n == 1) {

                    ret = EXCP_INTERRUPT; 

                    break;

                }

            }

        }

        /* timer IRQ */

        if (timer_irq_pending) {

#if defined (TARGET_I386)

            pic_set_irq(0, 1);

            pic_set_irq(0, 0);

            timer_irq_pending = 0;

            rtc_timer();

#endif

        }

        /* XXX: add explicit timer */

        SB16_run();

        /* run dma transfers, if any */

        DMA_run();

        /* VGA */

        if (gui_refresh_pending) {

            display_state.dpy_refresh(&display_state);

            gui_refresh_pending = 0;

        }

    }

    cpu_disable_ticks();

    return ret;

}

void help(void)

{

    printf("QEMU PC emulator version " QEMU_VERSION ", Copyright (c) 2003 Fabrice Bellard\n"

           "usage: %s [options] [disk_image]\n"

           "\n"

           "'disk_image' is a raw hard image image for IDE hard disk 0\n"

           "\n"

           "Standard options:\n"

           "-fda/-fdb file  use 'file' as floppy disk 0/1 image\n"

           "-hda/-hdb file  use 'file' as IDE hard disk 0/1 image\n"

           "-hdc/-hdd file  use 'file' as IDE hard disk 2/3 image\n"

           "-cdrom file     use 'file' as IDE cdrom 2 image\n"

           "-boot [a|b|c|d] boot on floppy (a, b), hard disk (c) or CD-ROM (d)\n"

           "-snapshot       write to temporary files instead of disk image files\n"

           "-m megs         set virtual RAM size to megs MB\n"

           "-n script       set network init script [default=%s]\n"

           "-tun-fd fd      this fd talks to tap/tun, use it.\n"

           "-nographic      disable graphical output\n"

           "\n"

           "Linux boot specific (does not require PC BIOS):\n"

           "-kernel bzImage use 'bzImage' as kernel image\n"

           "-append cmdline use 'cmdline' as kernel command line\n"

           "-initrd file    use 'file' as initial ram disk\n"

           "\n"

           "Debug/Expert options:\n"

           "-s              wait gdb connection to port %d\n"

           "-p port         change gdb connection port\n"

           "-d              output log to %s\n"

           "-hdachs c,h,s   force hard disk 0 geometry (usually qemu can guess it)\n"