void *pci_assign_dev_load_option_rom(PCIDevice *dev, struct Object *owner,

                                     int *size, unsigned int domain,

                                     unsigned int bus, unsigned int slot,

                                     unsigned int function)

{

    char name[32], rom_file[64];

    FILE *fp;

    uint8_t val;

    struct stat st;

    void *ptr = NULL;



    /* If loading ROM from file, pci handles it */

    if (dev->romfile || !dev->rom_bar) {

        return NULL;

    }



    snprintf(rom_file, sizeof(rom_file),

             "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/rom",

             domain, bus, slot, function);



    if (stat(rom_file, &st)) {

        if (errno != ENOENT) {

            error_report("pci-assign: Invalid ROM.");

        }

        return NULL;

    }



    /* Write "1" to the ROM file to enable it */

    fp = fopen(rom_file, "r+");

    if (fp == NULL) {

        error_report("pci-assign: Cannot open %s: %s", rom_file, strerror(errno));

        return NULL;

    }

    val = 1;

    if (fwrite(&val, 1, 1, fp) != 1) {

        goto close_rom;

    }

    fseek(fp, 0, SEEK_SET);



    snprintf(name, sizeof(name), "%s.rom", object_get_typename(owner));

    memory_region_init_ram(&dev->rom, owner, name, st.st_size, &error_abort);

    vmstate_register_ram(&dev->rom, &dev->qdev);

    ptr = memory_region_get_ram_ptr(&dev->rom);

    memset(ptr, 0xff, st.st_size);



    if (!fread(ptr, 1, st.st_size, fp)) {

        error_report("pci-assign: Cannot read from host %s", rom_file);

        error_printf("Device option ROM contents are probably invalid "

                     "(check dmesg).\nSkip option ROM probe with rombar=0, "

                     "or load from file with romfile=\n");

        goto close_rom;

    }



    pci_register_bar(dev, PCI_ROM_SLOT, 0, &dev->rom);

    dev->has_rom = true;

    *size = st.st_size;

close_rom:

    /* Write "0" to disable ROM */

    fseek(fp, 0, SEEK_SET);

    val = 0;

    if (!fwrite(&val, 1, 1, fp)) {

        DEBUG("%s\n", "Failed to disable pci-sysfs rom file");

    }

    fclose(fp);



    return ptr;

}
