static void s390_init(ram_addr_t my_ram_size,
                      const char *boot_device,
                      const char *kernel_filename,
                      const char *kernel_cmdline,
                      const char *initrd_filename,
                      const char *cpu_model)
{
    CPUState *env = NULL;
    MemoryRegion *sysmem = get_system_memory();
    MemoryRegion *ram = g_new(MemoryRegion, 1);
    ram_addr_t kernel_size = 0;
    ram_addr_t initrd_offset;
    ram_addr_t initrd_size = 0;
    int shift = 0;
    uint8_t *storage_keys;
    void *virtio_region;
    target_phys_addr_t virtio_region_len;
    target_phys_addr_t virtio_region_start;
    int i;
    /* s390x ram size detection needs a 16bit multiplier + an increment. So
       guests > 64GB can be specified in 2MB steps etc. */
    while ((my_ram_size >> (20 + shift)) > 65535) {
        shift++;
    }
    my_ram_size = my_ram_size >> (20 + shift) << (20 + shift);
    /* lets propagate the changed ram size into the global variable. */
    ram_size = my_ram_size;
    /* get a BUS */
    s390_bus = s390_virtio_bus_init(&my_ram_size);
    /* allocate RAM */
    memory_region_init_ram(ram, NULL, "s390.ram", my_ram_size);
    memory_region_add_subregion(sysmem, 0, ram);
    /* allocate storage keys */
    storage_keys = g_malloc0(my_ram_size / TARGET_PAGE_SIZE);
    /* init CPUs */
    if (cpu_model == NULL) {
        cpu_model = "host";
    }
    ipi_states = g_malloc(sizeof(CPUState *) * smp_cpus);
    for (i = 0; i < smp_cpus; i++) {
        CPUState *tmp_env;
        tmp_env = cpu_init(cpu_model);
        if (!env) {
            env = tmp_env;
        }
        ipi_states[i] = tmp_env;
        tmp_env->halted = 1;
        tmp_env->exception_index = EXCP_HLT;
        tmp_env->storage_keys = storage_keys;
    }
    /* One CPU has to run */
    s390_add_running_cpu(env);
    if (kernel_filename) {
        kernel_size = load_image(kernel_filename, qemu_get_ram_ptr(0));
        if (lduw_be_phys(KERN_IMAGE_START) != 0x0dd0) {
            fprintf(stderr, "Specified image is not an s390 boot image\n");
            exit(1);
        }
        env->psw.addr = KERN_IMAGE_START;
        env->psw.mask = 0x0000000180000000ULL;
    } else {
        ram_addr_t bios_size = 0;
        char *bios_filename;
        /* Load zipl bootloader */
        if (bios_name == NULL) {
            bios_name = ZIPL_FILENAME;
        }
        bios_filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
        bios_size = load_image(bios_filename, qemu_get_ram_ptr(ZIPL_LOAD_ADDR));
        g_free(bios_filename);
        if ((long)bios_size < 0) {
            hw_error("could not load bootloader '%s'\n", bios_name);
        }
        if (bios_size > 4096) {
            hw_error("stage1 bootloader is > 4k\n");
        }
        env->psw.addr = ZIPL_START;
        env->psw.mask = 0x0000000180000000ULL;
    }
    if (initrd_filename) {
        initrd_offset = INITRD_START;
        while (kernel_size + 0x100000 > initrd_offset) {
            initrd_offset += 0x100000;
        }
        initrd_size = load_image(initrd_filename, qemu_get_ram_ptr(initrd_offset));
        stq_be_phys(INITRD_PARM_START, initrd_offset);
        stq_be_phys(INITRD_PARM_SIZE, initrd_size);
    }
    if (kernel_cmdline) {
        cpu_physical_memory_write(KERN_PARM_AREA, kernel_cmdline,
                                  strlen(kernel_cmdline) + 1);
    }
    /* Create VirtIO network adapters */
    for(i = 0; i < nb_nics; i++) {
        NICInfo *nd = &nd_table[i];
        DeviceState *dev;
        if (!nd->model) {
            nd->model = g_strdup("virtio");
        }
        if (strcmp(nd->model, "virtio")) {
            fprintf(stderr, "S390 only supports VirtIO nics\n");
            exit(1);
        }
        dev = qdev_create((BusState *)s390_bus, "virtio-net-s390");
        qdev_set_nic_properties(dev, nd);
        qdev_init_nofail(dev);
    }
    /* Create VirtIO disk drives */
    for(i = 0; i < MAX_BLK_DEVS; i++) {
        DriveInfo *dinfo;
        DeviceState *dev;
        dinfo = drive_get(IF_IDE, 0, i);
        if (!dinfo) {
            continue;
        }
        dev = qdev_create((BusState *)s390_bus, "virtio-blk-s390");
        qdev_prop_set_drive_nofail(dev, "drive", dinfo->bdrv);
        qdev_init_nofail(dev);
    }
}