Archipelago » qemu

/*

 * QEMU PC 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 "hw.h"

#include "pc.h"

#include "fdc.h"

#include "pci.h"

#include "block.h"

#include "sysemu.h"

#include "audio/audio.h"

#include "net.h"

#include "smbus.h"

#include "boards.h"

#include "monitor.h"

#include "fw_cfg.h"

#include "hpet_emul.h"

#include "watchdog.h"

#include "smbios.h"

/* output Bochs bios info messages */

//#define DEBUG_BIOS

/* Show multiboot debug output */

//#define DEBUG_MULTIBOOT

#define BIOS_FILENAME "bios.bin"

#define VGABIOS_FILENAME "vgabios.bin"

#define VGABIOS_CIRRUS_FILENAME "vgabios-cirrus.bin"

#define PC_MAX_BIOS_SIZE (4 * 1024 * 1024)

/* Leave a chunk of memory at the top of RAM for the BIOS ACPI tables.  */

#define ACPI_DATA_SIZE       0x10000

#define BIOS_CFG_IOPORT 0x510

#define FW_CFG_ACPI_TABLES (FW_CFG_ARCH_LOCAL + 0)

#define FW_CFG_SMBIOS_ENTRIES (FW_CFG_ARCH_LOCAL + 1)

#define FW_CFG_IRQ0_OVERRIDE (FW_CFG_ARCH_LOCAL + 2)

#define MAX_IDE_BUS 2

static fdctrl_t *floppy_controller;

static RTCState *rtc_state;

static PITState *pit;

static PCIDevice *i440fx_state;

typedef struct rom_reset_data {

    uint8_t *data;

    target_phys_addr_t addr;

    unsigned size;

} RomResetData;

static void option_rom_reset(void *_rrd)

{

    RomResetData *rrd = _rrd;

    cpu_physical_memory_write_rom(rrd->addr, rrd->data, rrd->size);

}

static void option_rom_setup_reset(target_phys_addr_t addr, unsigned size)

{

    RomResetData *rrd = qemu_malloc(sizeof *rrd);

    rrd->data = qemu_malloc(size);

    cpu_physical_memory_read(addr, rrd->data, size);

    rrd->addr = addr;

    rrd->size = size;

    qemu_register_reset(option_rom_reset, rrd);

}

typedef struct isa_irq_state {

    qemu_irq *i8259;

    qemu_irq *ioapic;

} IsaIrqState;

static void isa_irq_handler(void *opaque, int n, int level)

{

    IsaIrqState *isa = (IsaIrqState *)opaque;

    if (n < 16) {

        qemu_set_irq(isa->i8259[n], level);

    }

    qemu_set_irq(isa->ioapic[n], level);

};

static void ioport80_write(void *opaque, uint32_t addr, uint32_t data)

{

}

/* MSDOS compatibility mode FPU exception support */

static qemu_irq ferr_irq;

/* XXX: add IGNNE support */

void cpu_set_ferr(CPUX86State *s)

{

    qemu_irq_raise(ferr_irq);

}

static void ioportF0_write(void *opaque, uint32_t addr, uint32_t data)

{

    qemu_irq_lower(ferr_irq);

}

/* TSC handling */

uint64_t cpu_get_tsc(CPUX86State *env)

{

    return cpu_get_ticks();

}

/* SMM support */

void cpu_smm_update(CPUState *env)

{

    if (i440fx_state && env == first_cpu)

        i440fx_set_smm(i440fx_state, (env->hflags >> HF_SMM_SHIFT) & 1);

}

/* IRQ handling */

int cpu_get_pic_interrupt(CPUState *env)

{

    int intno;

    intno = apic_get_interrupt(env);

    if (intno >= 0) {

        /* set irq request if a PIC irq is still pending */

        /* XXX: improve that */

        pic_update_irq(isa_pic);

        return intno;

    }

    /* read the irq from the PIC */

    if (!apic_accept_pic_intr(env))

        return -1;

    intno = pic_read_irq(isa_pic);

    return intno;

}

static void pic_irq_request(void *opaque, int irq, int level)

{

    CPUState *env = first_cpu;

    if (env->apic_state) {

        while (env) {

            if (apic_accept_pic_intr(env))

                apic_deliver_pic_intr(env, level);

            env = env->next_cpu;

        }

    } else {

        if (level)

            cpu_interrupt(env, CPU_INTERRUPT_HARD);

        else

            cpu_reset_interrupt(env, CPU_INTERRUPT_HARD);

    }

}

/* PC cmos mappings */

#define REG_EQUIPMENT_BYTE          0x14

static int cmos_get_fd_drive_type(int fd0)

{

    int val;

    switch (fd0) {

    case 0:

        /* 1.44 Mb 3"5 drive */

        val = 4;

        break;

    case 1:

        /* 2.88 Mb 3"5 drive */

        val = 5;

        break;

    case 2:

        /* 1.2 Mb 5"5 drive */

        val = 2;

        break;

    default:

        val = 0;

        break;

    }

    return val;

}

static void cmos_init_hd(int type_ofs, int info_ofs, BlockDriverState *hd)

{

    RTCState *s = rtc_state;

    int cylinders, heads, sectors;

    bdrv_get_geometry_hint(hd, &cylinders, &heads, &sectors);

    rtc_set_memory(s, type_ofs, 47);

    rtc_set_memory(s, info_ofs, cylinders);

    rtc_set_memory(s, info_ofs + 1, cylinders >> 8);

    rtc_set_memory(s, info_ofs + 2, heads);

    rtc_set_memory(s, info_ofs + 3, 0xff);

    rtc_set_memory(s, info_ofs + 4, 0xff);

    rtc_set_memory(s, info_ofs + 5, 0xc0 | ((heads > 8) << 3));

    rtc_set_memory(s, info_ofs + 6, cylinders);

    rtc_set_memory(s, info_ofs + 7, cylinders >> 8);

    rtc_set_memory(s, info_ofs + 8, sectors);

}

/* convert boot_device letter to something recognizable by the bios */

static int boot_device2nibble(char boot_device)

{

    switch(boot_device) {

    case 'a':

    case 'b':

        return 0x01; /* floppy boot */

    case 'c':

        return 0x02; /* hard drive boot */

    case 'd':

        return 0x03; /* CD-ROM boot */

    case 'n':

        return 0x04; /* Network boot */

    }

    return 0;

}

/* copy/pasted from cmos_init, should be made a general function

 and used there as well */

static int pc_boot_set(void *opaque, const char *boot_device)

{

    Monitor *mon = cur_mon;

#define PC_MAX_BOOT_DEVICES 3

    RTCState *s = (RTCState *)opaque;

    int nbds, bds[3] = { 0, };

    int i;

    nbds = strlen(boot_device);

    if (nbds > PC_MAX_BOOT_DEVICES) {

        monitor_printf(mon, "Too many boot devices for PC\n");

        return(1);

    }

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

        bds[i] = boot_device2nibble(boot_device[i]);

        if (bds[i] == 0) {

            monitor_printf(mon, "Invalid boot device for PC: '%c'\n",

                           boot_device[i]);

            return(1);

        }

    }

    rtc_set_memory(s, 0x3d, (bds[1] << 4) | bds[0]);

    rtc_set_memory(s, 0x38, (bds[2] << 4));

    return(0);

}

/* hd_table must contain 4 block drivers */

static void cmos_init(ram_addr_t ram_size, ram_addr_t above_4g_mem_size,

                      const char *boot_device, BlockDriverState **hd_table)

{

    RTCState *s = rtc_state;

    int nbds, bds[3] = { 0, };

    int val;

    int fd0, fd1, nb;

    int i;

    /* various important CMOS locations needed by PC/Bochs bios */

    /* memory size */

    val = 640; /* base memory in K */

    rtc_set_memory(s, 0x15, val);

    rtc_set_memory(s, 0x16, val >> 8);

    val = (ram_size / 1024) - 1024;

    if (val > 65535)

        val = 65535;

    rtc_set_memory(s, 0x17, val);

    rtc_set_memory(s, 0x18, val >> 8);

    rtc_set_memory(s, 0x30, val);

    rtc_set_memory(s, 0x31, val >> 8);

    if (above_4g_mem_size) {

        rtc_set_memory(s, 0x5b, (unsigned int)above_4g_mem_size >> 16);

        rtc_set_memory(s, 0x5c, (unsigned int)above_4g_mem_size >> 24);

        rtc_set_memory(s, 0x5d, (uint64_t)above_4g_mem_size >> 32);

    }

    if (ram_size > (16 * 1024 * 1024))

        val = (ram_size / 65536) - ((16 * 1024 * 1024) / 65536);

    else

        val = 0;

    if (val > 65535)

        val = 65535;

    rtc_set_memory(s, 0x34, val);

    rtc_set_memory(s, 0x35, val >> 8);

    /* set the number of CPU */

    rtc_set_memory(s, 0x5f, smp_cpus - 1);

    /* set boot devices, and disable floppy signature check if requested */

#define PC_MAX_BOOT_DEVICES 3

    nbds = strlen(boot_device);

    if (nbds > PC_MAX_BOOT_DEVICES) {

        fprintf(stderr, "Too many boot devices for PC\n");

        exit(1);

    }

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

        bds[i] = boot_device2nibble(boot_device[i]);

        if (bds[i] == 0) {

            fprintf(stderr, "Invalid boot device for PC: '%c'\n",

                    boot_device[i]);

            exit(1);

        }

    }

    rtc_set_memory(s, 0x3d, (bds[1] << 4) | bds[0]);

    rtc_set_memory(s, 0x38, (bds[2] << 4) | (fd_bootchk ?  0x0 : 0x1));

    /* floppy type */

    fd0 = fdctrl_get_drive_type(floppy_controller, 0);

    fd1 = fdctrl_get_drive_type(floppy_controller, 1);

    val = (cmos_get_fd_drive_type(fd0) << 4) | cmos_get_fd_drive_type(fd1);

    rtc_set_memory(s, 0x10, val);

    val = 0;

    nb = 0;

    if (fd0 < 3)

        nb++;

    if (fd1 < 3)

        nb++;

    switch (nb) {

    case 0:

        break;

    case 1:

        val |= 0x01; /* 1 drive, ready for boot */

        break;

    case 2:

        val |= 0x41; /* 2 drives, ready for boot */

        break;

    }

    val |= 0x02; /* FPU is there */

    val |= 0x04; /* PS/2 mouse installed */

    rtc_set_memory(s, REG_EQUIPMENT_BYTE, val);

    /* hard drives */

    rtc_set_memory(s, 0x12, (hd_table[0] ? 0xf0 : 0) | (hd_table[1] ? 0x0f : 0));

    if (hd_table[0])

        cmos_init_hd(0x19, 0x1b, hd_table[0]);

    if (hd_table[1])

        cmos_init_hd(0x1a, 0x24, hd_table[1]);

    val = 0;

    for (i = 0; i < 4; i++) {

        if (hd_table[i]) {

            int cylinders, heads, sectors, translation;

            /* NOTE: bdrv_get_geometry_hint() returns the physical

                geometry.  It is always such that: 1 <= sects <= 63, 1

                <= heads <= 16, 1 <= cylinders <= 16383. The BIOS

                geometry can be different if a translation is done. */

            translation = bdrv_get_translation_hint(hd_table[i]);

            if (translation == BIOS_ATA_TRANSLATION_AUTO) {

                bdrv_get_geometry_hint(hd_table[i], &cylinders, &heads, &sectors);

                if (cylinders <= 1024 && heads <= 16 && sectors <= 63) {

                    /* No translation. */

                    translation = 0;

                } else {

                    /* LBA translation. */

                    translation = 1;

                }

            } else {

                translation--;

            }

            val |= translation << (i * 2);

        }

    }

    rtc_set_memory(s, 0x39, val);

}

void ioport_set_a20(int enable)

{

    /* XXX: send to all CPUs ? */

    cpu_x86_set_a20(first_cpu, enable);

}

int ioport_get_a20(void)

{

    return ((first_cpu->a20_mask >> 20) & 1);

}

static void ioport92_write(void *opaque, uint32_t addr, uint32_t val)

{

    ioport_set_a20((val >> 1) & 1);

    /* XXX: bit 0 is fast reset */

}

static uint32_t ioport92_read(void *opaque, uint32_t addr)

{

    return ioport_get_a20() << 1;

}

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

/* Bochs BIOS debug ports */

static void bochs_bios_write(void *opaque, uint32_t addr, uint32_t val)

{

    static const char shutdown_str[8] = "Shutdown";

    static int shutdown_index = 0;

    switch(addr) {

        /* Bochs BIOS messages */

    case 0x400:

    case 0x401:

        fprintf(stderr, "BIOS panic at rombios.c, line %d\n", val);

        exit(1);

    case 0x402:

    case 0x403:

#ifdef DEBUG_BIOS

        fprintf(stderr, "%c", val);

#endif

        break;

    case 0x8900:

        /* same as Bochs power off */

        if (val == shutdown_str[shutdown_index]) {

            shutdown_index++;

            if (shutdown_index == 8) {

                shutdown_index = 0;

                qemu_system_shutdown_request();

            }

        } else {

            shutdown_index = 0;

        }

        break;

        /* LGPL'ed VGA BIOS messages */

    case 0x501:

    case 0x502:

        fprintf(stderr, "VGA BIOS panic, line %d\n", val);

        exit(1);

    case 0x500:

    case 0x503:

#ifdef DEBUG_BIOS

        fprintf(stderr, "%c", val);

#endif

        break;

    }

}

extern uint64_t node_cpumask[MAX_NODES];

static void *bochs_bios_init(void)

{

    void *fw_cfg;

    uint8_t *smbios_table;

    size_t smbios_len;

    uint64_t *numa_fw_cfg;

    int i, j;

    register_ioport_write(0x400, 1, 2, bochs_bios_write, NULL);

    register_ioport_write(0x401, 1, 2, bochs_bios_write, NULL);

    register_ioport_write(0x402, 1, 1, bochs_bios_write, NULL);

    register_ioport_write(0x403, 1, 1, bochs_bios_write, NULL);

    register_ioport_write(0x8900, 1, 1, bochs_bios_write, NULL);

    register_ioport_write(0x501, 1, 2, bochs_bios_write, NULL);

    register_ioport_write(0x502, 1, 2, bochs_bios_write, NULL);

    register_ioport_write(0x500, 1, 1, bochs_bios_write, NULL);

    register_ioport_write(0x503, 1, 1, bochs_bios_write, NULL);

    fw_cfg = fw_cfg_init(BIOS_CFG_IOPORT, BIOS_CFG_IOPORT + 1, 0, 0);

    fw_cfg_add_i32(fw_cfg, FW_CFG_ID, 1);

    fw_cfg_add_i64(fw_cfg, FW_CFG_RAM_SIZE, (uint64_t)ram_size);

    fw_cfg_add_bytes(fw_cfg, FW_CFG_ACPI_TABLES, (uint8_t *)acpi_tables,

                     acpi_tables_len);

    fw_cfg_add_bytes(fw_cfg, FW_CFG_IRQ0_OVERRIDE, &irq0override, 1);

    smbios_table = smbios_get_table(&smbios_len);

    if (smbios_table)

        fw_cfg_add_bytes(fw_cfg, FW_CFG_SMBIOS_ENTRIES,

                         smbios_table, smbios_len);

    /* allocate memory for the NUMA channel: one (64bit) word for the number

     * of nodes, one word for each VCPU->node and one word for each node to

     * hold the amount of memory.

     */

    numa_fw_cfg = qemu_mallocz((1 + smp_cpus + nb_numa_nodes) * 8);

    numa_fw_cfg[0] = cpu_to_le64(nb_numa_nodes);

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

        for (j = 0; j < nb_numa_nodes; j++) {

            if (node_cpumask[j] & (1 << i)) {

                numa_fw_cfg[i + 1] = cpu_to_le64(j);

                break;

            }

        }

    }

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

        numa_fw_cfg[smp_cpus + 1 + i] = cpu_to_le64(node_mem[i]);

    }

    fw_cfg_add_bytes(fw_cfg, FW_CFG_NUMA, (uint8_t *)numa_fw_cfg,

                     (1 + smp_cpus + nb_numa_nodes) * 8);

    return fw_cfg;

}

/* Generate an initial boot sector which sets state and jump to

   a specified vector */

static void generate_bootsect(target_phys_addr_t option_rom,

                              uint32_t gpr[8], uint16_t segs[6], uint16_t ip)

{

    uint8_t rom[512], *p, *reloc;

    uint8_t sum;

    int i;

    memset(rom, 0, sizeof(rom));

    p = rom;

    /* Make sure we have an option rom signature */

    *p++ = 0x55;

    *p++ = 0xaa;

    /* ROM size in sectors*/

    *p++ = 1;

    /* Hook int19 */

    *p++ = 0x50;                /* push ax */

    *p++ = 0x1e;                /* push ds */

    *p++ = 0x31; *p++ = 0xc0;        /* xor ax, ax */

    *p++ = 0x8e; *p++ = 0xd8;        /* mov ax, ds */

    *p++ = 0xc7; *p++ = 0x06;   /* movvw _start,0x64 */

    *p++ = 0x64; *p++ = 0x00;

    reloc = p;

    *p++ = 0x00; *p++ = 0x00;

    *p++ = 0x8c; *p++ = 0x0e;   /* mov cs,0x66 */

    *p++ = 0x66; *p++ = 0x00;

    *p++ = 0x1f;                /* pop ds */

    *p++ = 0x58;                /* pop ax */

    *p++ = 0xcb;                /* lret */

    /* Actual code */

    *reloc = (p - rom);

    *p++ = 0xfa;                /* CLI */

    *p++ = 0xfc;                /* CLD */

    for (i = 0; i < 6; i++) {

        if (i == 1)                /* Skip CS */

            continue;

        *p++ = 0xb8;                /* MOV AX,imm16 */

        *p++ = segs[i];

        *p++ = segs[i] >> 8;

        *p++ = 0x8e;                /* MOV <seg>,AX */

        *p++ = 0xc0 + (i << 3);

    }

    for (i = 0; i < 8; i++) {

        *p++ = 0x66;                /* 32-bit operand size */

        *p++ = 0xb8 + i;        /* MOV <reg>,imm32 */

        *p++ = gpr[i];

        *p++ = gpr[i] >> 8;

        *p++ = gpr[i] >> 16;

        *p++ = gpr[i] >> 24;

    }

    *p++ = 0xea;                /* JMP FAR */

    *p++ = ip;                        /* IP */

    *p++ = ip >> 8;

    *p++ = segs[1];                /* CS */

    *p++ = segs[1] >> 8;

    /* sign rom */

    sum = 0;

    for (i = 0; i < (sizeof(rom) - 1); i++)

        sum += rom[i];

    rom[sizeof(rom) - 1] = -sum;

    cpu_physical_memory_write_rom(option_rom, rom, sizeof(rom));

    option_rom_setup_reset(option_rom, sizeof (rom));

}

static long get_file_size(FILE *f)

{

    long where, size;

    /* XXX: on Unix systems, using fstat() probably makes more sense */

    where = ftell(f);

    fseek(f, 0, SEEK_END);

    size = ftell(f);

    fseek(f, where, SEEK_SET);

    return size;

}

#define MULTIBOOT_STRUCT_ADDR 0x9000

#if MULTIBOOT_STRUCT_ADDR > 0xf0000

#error multiboot struct needs to fit in 16 bit real mode

#endif

static int load_multiboot(void *fw_cfg,

                          FILE *f,

                          const char *kernel_filename,

                          const char *initrd_filename,

                          const char *kernel_cmdline,

                          uint8_t *header)

{

    int i, t, is_multiboot = 0;

    uint32_t flags = 0;

    uint32_t mh_entry_addr;

    uint32_t mh_load_addr;

    uint32_t mb_kernel_size;

    uint32_t mmap_addr = MULTIBOOT_STRUCT_ADDR;

    uint32_t mb_bootinfo = MULTIBOOT_STRUCT_ADDR + 0x500;

    uint32_t mb_cmdline = mb_bootinfo + 0x200;

    uint32_t mb_mod_end;

    /* Ok, let's see if it is a multiboot image.

       The header is 12x32bit long, so the latest entry may be 8192 - 48. */

    for (i = 0; i < (8192 - 48); i += 4) {

        if (ldl_p(header+i) == 0x1BADB002) {

            uint32_t checksum = ldl_p(header+i+8);

            flags = ldl_p(header+i+4);

            checksum += flags;

            checksum += (uint32_t)0x1BADB002;

            if (!checksum) {

                is_multiboot = 1;

                break;

            }

        }

    }

    if (!is_multiboot)

        return 0; /* no multiboot */

#ifdef DEBUG_MULTIBOOT

    fprintf(stderr, "qemu: I believe we found a multiboot image!\n");

#endif

    if (flags & 0x00000004) { /* MULTIBOOT_HEADER_HAS_VBE */

        fprintf(stderr, "qemu: multiboot knows VBE. we don't.\n");

    }

    if (!(flags & 0x00010000)) { /* MULTIBOOT_HEADER_HAS_ADDR */

        uint64_t elf_entry;

        int kernel_size;

        fclose(f);

        kernel_size = load_elf(kernel_filename, 0, &elf_entry, NULL, NULL);

        if (kernel_size < 0) {

            fprintf(stderr, "Error while loading elf kernel\n");

            exit(1);

        }

        mh_load_addr = mh_entry_addr = elf_entry;

        mb_kernel_size = kernel_size;

#ifdef DEBUG_MULTIBOOT

        fprintf(stderr, "qemu: loading multiboot-elf kernel (%#x bytes) with entry %#zx\n",

                mb_kernel_size, (size_t)mh_entry_addr);

#endif

    } else {

        /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_ADDR. */

        uint32_t mh_header_addr = ldl_p(header+i+12);

        mh_load_addr = ldl_p(header+i+16);

#ifdef DEBUG_MULTIBOOT

        uint32_t mh_load_end_addr = ldl_p(header+i+20);

        uint32_t mh_bss_end_addr = ldl_p(header+i+24);

#endif

        uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);

        mh_entry_addr = ldl_p(header+i+28);

        mb_kernel_size = get_file_size(f) - mb_kernel_text_offset;

        /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_VBE.

        uint32_t mh_mode_type = ldl_p(header+i+32);

        uint32_t mh_width = ldl_p(header+i+36);

        uint32_t mh_height = ldl_p(header+i+40);

        uint32_t mh_depth = ldl_p(header+i+44); */

#ifdef DEBUG_MULTIBOOT

        fprintf(stderr, "multiboot: mh_header_addr = %#x\n", mh_header_addr);

        fprintf(stderr, "multiboot: mh_load_addr = %#x\n", mh_load_addr);

        fprintf(stderr, "multiboot: mh_load_end_addr = %#x\n", mh_load_end_addr);

        fprintf(stderr, "multiboot: mh_bss_end_addr = %#x\n", mh_bss_end_addr);

#endif

        fseek(f, mb_kernel_text_offset, SEEK_SET);

#ifdef DEBUG_MULTIBOOT

        fprintf(stderr, "qemu: loading multiboot kernel (%#x bytes) at %#x\n",

                mb_kernel_size, mh_load_addr);

#endif

        if (!fread_targphys_ok(mh_load_addr, mb_kernel_size, f)) {

            fprintf(stderr, "qemu: read error on multiboot kernel '%s' (%#x)\n",

                    kernel_filename, mb_kernel_size);

            exit(1);

        }

        fclose(f);

    }

    /* blob size is only the kernel for now */

    mb_mod_end = mh_load_addr + mb_kernel_size;

    /* load modules */

    stl_phys(mb_bootinfo + 20, 0x0); /* mods_count */

    if (initrd_filename) {

        uint32_t mb_mod_info = mb_bootinfo + 0x100;

        uint32_t mb_mod_cmdline = mb_bootinfo + 0x300;

        uint32_t mb_mod_start = mh_load_addr;

        uint32_t mb_mod_length = mb_kernel_size;

        char *next_initrd;

        char *next_space;

        int mb_mod_count = 0;

        do {

            next_initrd = strchr(initrd_filename, ',');

            if (next_initrd)

                *next_initrd = '\0';

            /* if a space comes after the module filename, treat everything

               after that as parameters */

            cpu_physical_memory_write(mb_mod_cmdline, (uint8_t*)initrd_filename,

                                      strlen(initrd_filename) + 1);

            stl_phys(mb_mod_info + 8, mb_mod_cmdline); /* string */

            mb_mod_cmdline += strlen(initrd_filename) + 1;

            if ((next_space = strchr(initrd_filename, ' ')))

                *next_space = '\0';

#ifdef DEBUG_MULTIBOOT

             printf("multiboot loading module: %s\n", initrd_filename);

#endif

            f = fopen(initrd_filename, "rb");

            if (f) {

                mb_mod_start = (mb_mod_start + mb_mod_length + (TARGET_PAGE_SIZE - 1))

                             & (TARGET_PAGE_MASK);

                mb_mod_length = get_file_size(f);

                mb_mod_end = mb_mod_start + mb_mod_length;

                if (!fread_targphys_ok(mb_mod_start, mb_mod_length, f)) {

                    fprintf(stderr, "qemu: read error on multiboot module '%s' (%#x)\n",

                            initrd_filename, mb_mod_length);

                    exit(1);

                }

                mb_mod_count++;

                stl_phys(mb_mod_info + 0, mb_mod_start);

                stl_phys(mb_mod_info + 4, mb_mod_start + mb_mod_length);

#ifdef DEBUG_MULTIBOOT

                printf("mod_start: %#x\nmod_end:   %#x\n", mb_mod_start,

                       mb_mod_start + mb_mod_length);

#endif

                stl_phys(mb_mod_info + 12, 0x0); /* reserved */

            }

            initrd_filename = next_initrd+1;

            mb_mod_info += 16;

        } while (next_initrd);

        stl_phys(mb_bootinfo + 20, mb_mod_count); /* mods_count */

        stl_phys(mb_bootinfo + 24, mb_bootinfo + 0x100); /* mods_addr */

    }

    /* Make sure we're getting kernel + modules back after reset */

    option_rom_setup_reset(mh_load_addr, mb_mod_end - mh_load_addr);

    /* Commandline support */

    stl_phys(mb_bootinfo + 16, mb_cmdline);

    t = strlen(kernel_filename);

    cpu_physical_memory_write(mb_cmdline, (uint8_t*)kernel_filename, t);

    mb_cmdline += t;

    stb_phys(mb_cmdline++, ' ');

    t = strlen(kernel_cmdline) + 1;

    cpu_physical_memory_write(mb_cmdline, (uint8_t*)kernel_cmdline, t);

    /* the kernel is where we want it to be now */

#define MULTIBOOT_FLAGS_MEMORY (1 << 0)

#define MULTIBOOT_FLAGS_BOOT_DEVICE (1 << 1)

#define MULTIBOOT_FLAGS_CMDLINE (1 << 2)

#define MULTIBOOT_FLAGS_MODULES (1 << 3)

#define MULTIBOOT_FLAGS_MMAP (1 << 6)

    stl_phys(mb_bootinfo, MULTIBOOT_FLAGS_MEMORY

                        | MULTIBOOT_FLAGS_BOOT_DEVICE

                        | MULTIBOOT_FLAGS_CMDLINE

                        | MULTIBOOT_FLAGS_MODULES

                        | MULTIBOOT_FLAGS_MMAP);

    stl_phys(mb_bootinfo + 4, 640); /* mem_lower */

    stl_phys(mb_bootinfo + 8, ram_size / 1024); /* mem_upper */

    stl_phys(mb_bootinfo + 12, 0x8001ffff); /* XXX: use the -boot switch? */

    stl_phys(mb_bootinfo + 48, mmap_addr); /* mmap_addr */

#ifdef DEBUG_MULTIBOOT

    fprintf(stderr, "multiboot: mh_entry_addr = %#x\n", mh_entry_addr);

#endif

    /* Pass variables to option rom */

    fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, mh_entry_addr);

    fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_ADDR, mb_bootinfo);

    fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_SIZE, mmap_addr);

    /* Make sure we're getting the config space back after reset */

    option_rom_setup_reset(mb_bootinfo, 0x500);

    option_rom[nb_option_roms] = "multiboot.bin";

    nb_option_roms++;

    return 1; /* yes, we are multiboot */

}

static void load_linux(void *fw_cfg,

                       target_phys_addr_t option_rom,

                       const char *kernel_filename,

                       const char *initrd_filename,

                       const char *kernel_cmdline,

               target_phys_addr_t max_ram_size)

{

    uint16_t protocol;

    uint32_t gpr[8];

    uint16_t seg[6];

    uint16_t real_seg;

    int setup_size, kernel_size, initrd_size = 0, cmdline_size;

    uint32_t initrd_max;

    uint8_t header[8192];

    target_phys_addr_t real_addr, prot_addr, cmdline_addr, initrd_addr = 0;

    FILE *f, *fi;

    char *vmode;

    /* Align to 16 bytes as a paranoia measure */

    cmdline_size = (strlen(kernel_cmdline)+16) & ~15;

    /* load the kernel header */

    f = fopen(kernel_filename, "rb");

    if (!f || !(kernel_size = get_file_size(f)) ||

        fread(header, 1, MIN(ARRAY_SIZE(header), kernel_size), f) !=

        MIN(ARRAY_SIZE(header), kernel_size)) {

        fprintf(stderr, "qemu: could not load kernel '%s'\n",

                kernel_filename);

        exit(1);

    }

    /* kernel protocol version */

#if 0

    fprintf(stderr, "header magic: %#x\n", ldl_p(header+0x202));

#endif

    if (ldl_p(header+0x202) == 0x53726448)

        protocol = lduw_p(header+0x206);

    else {

        /* This looks like a multiboot kernel. If it is, let's stop

           treating it like a Linux kernel. */

        if (load_multiboot(fw_cfg, f, kernel_filename,

                           initrd_filename, kernel_cmdline, header))

           return;

        protocol = 0;

    }

    if (protocol < 0x200 || !(header[0x211] & 0x01)) {

        /* Low kernel */

        real_addr    = 0x90000;

        cmdline_addr = 0x9a000 - cmdline_size;

        prot_addr    = 0x10000;