启动x86虚拟机

1057/* First C function to be called on Xen boot */

1058asmlinkage void __init xen_start_kernel(void)

1059{

1060        pgd_t *pgd;

1061

……

1201

1202        /* Start the world */

1203#ifdef CONFIG_X86_32

1204        i386_start_kernel();

1205#else

1206        x86_64_start_reservations((char *)__pa_symbol(&boot_params));

1207#endif

1208}

  31void __init i386_start_kernel(void)

  32{

  33#ifdef CONFIG_X86_TRAMPOLINE

  34        /*

  35         * But first pinch a few for the stack/trampoline stuff

  36         * FIXME: Don't need the extra page at 4K, but need to fix

  37         * trampoline before removing it. (see the GDT stuff)

  38         */

  39        reserve_early_overlap_ok(PAGE_SIZE, PAGE_SIZE + PAGE_SIZE,

  40                                         "EX TRAMPOLINE");

  41#endif

  42

  43        reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");

  44

  45#ifdef CONFIG_BLK_DEV_INITRD

  46        /* Reserve INITRD */

  47        if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {

  48                /* Assume only end is not page aligned */

  49                u64 ramdisk_image = boot_params.hdr.ramdisk_image;

  50                u64 ramdisk_size  = boot_params.hdr.ramdisk_size;

  51                u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);

  52                reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");

  53        }

  54#endif

  55

  56        /* Call the subarch specific early setup function */

  57        switch (boot_params.hdr.hardware_subarch) {

  58        case X86_SUBARCH_MRST:

  59                x86_mrst_early_setup();

  60                break;

  61        default:

  62                i386_default_early_setup();

  63                break;

  64        }

  65

  66        /*

  67         * At this point everything still needed from the boot loader

  68         * or BIOS or kernel text should be early reserved or marked not

  69         * RAM in e820. All other memory is free game.

  70         */

  71

  72        start_kernel();

  73}

static void __init i386_default_early_setup(void)

{

       /* Initilize 32bit specific setup functions */

       x86_init.resources.probe_roms = probe_roms;

       x86_init.resources.reserve_resources = i386_reserve_resources;

       x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc;

       reserve_ebda_region();

}