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Use an option rom instead of boot sector for -kernel
Generate an option rom instead of using a hijacked boot sector for kernel booting. This just requires adding a small option ROM header and a few more instructions to the boot sector to take over the int19 vector and run our boot code. A disk is no longer needed when using -kernel on x86. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5650 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori
parent
6223246ad9
commit
4fc9af53d8
32
block.c
32
block.c
@ -527,14 +527,6 @@ int bdrv_read(BlockDriverState *bs, int64_t sector_num,
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if (!drv)
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return -ENOMEDIUM;
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if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
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memcpy(buf, bs->boot_sector_data, 512);
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sector_num++;
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nb_sectors--;
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buf += 512;
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if (nb_sectors == 0)
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return 0;
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}
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if (drv->bdrv_pread) {
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int ret, len;
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len = nb_sectors * 512;
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@ -567,9 +559,6 @@ int bdrv_write(BlockDriverState *bs, int64_t sector_num,
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return -ENOMEDIUM;
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if (bs->read_only)
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return -EACCES;
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if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
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memcpy(bs->boot_sector_data, buf, 512);
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}
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if (drv->bdrv_pwrite) {
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int ret, len;
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len = nb_sectors * 512;
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@ -750,16 +739,6 @@ void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
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*nb_sectors_ptr = length;
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}
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/* force a given boot sector. */
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void bdrv_set_boot_sector(BlockDriverState *bs, const uint8_t *data, int size)
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{
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bs->boot_sector_enabled = 1;
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if (size > 512)
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size = 512;
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memcpy(bs->boot_sector_data, data, size);
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memset(bs->boot_sector_data + size, 0, 512 - size);
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}
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void bdrv_set_geometry_hint(BlockDriverState *bs,
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int cyls, int heads, int secs)
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{
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@ -1155,14 +1134,6 @@ BlockDriverAIOCB *bdrv_aio_read(BlockDriverState *bs, int64_t sector_num,
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if (!drv)
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return NULL;
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/* XXX: we assume that nb_sectors == 0 is suppored by the async read */
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if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
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memcpy(buf, bs->boot_sector_data, 512);
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sector_num++;
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nb_sectors--;
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buf += 512;
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}
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ret = drv->bdrv_aio_read(bs, sector_num, buf, nb_sectors, cb, opaque);
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if (ret) {
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@ -1185,9 +1156,6 @@ BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs, int64_t sector_num,
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return NULL;
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if (bs->read_only)
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return NULL;
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if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
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memcpy(bs->boot_sector_data, buf, 512);
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}
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ret = drv->bdrv_aio_write(bs, sector_num, buf, nb_sectors, cb, opaque);
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1
block.h
1
block.h
@ -79,7 +79,6 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset);
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int64_t bdrv_getlength(BlockDriverState *bs);
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void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
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int bdrv_commit(BlockDriverState *bs);
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void bdrv_set_boot_sector(BlockDriverState *bs, const uint8_t *data, int size);
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/* async block I/O */
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typedef struct BlockDriverAIOCB BlockDriverAIOCB;
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typedef void BlockDriverCompletionFunc(void *opaque, int ret);
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@ -104,9 +104,6 @@ struct BlockDriverState {
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BlockDriver *drv; /* NULL means no media */
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void *opaque;
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int boot_sector_enabled;
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uint8_t boot_sector_data[512];
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char filename[1024];
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char backing_file[1024]; /* if non zero, the image is a diff of
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this file image */
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72
hw/pc.c
72
hw/pc.c
@ -438,30 +438,45 @@ static void bochs_bios_init(void)
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/* Generate an initial boot sector which sets state and jump to
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a specified vector */
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static void generate_bootsect(uint32_t gpr[8], uint16_t segs[6], uint16_t ip)
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static void generate_bootsect(uint8_t *option_rom,
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uint32_t gpr[8], uint16_t segs[6], uint16_t ip)
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{
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uint8_t bootsect[512], *p;
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uint8_t rom[512], *p, *reloc;
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uint8_t sum;
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int i;
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int hda;
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hda = drive_get_index(IF_IDE, 0, 0);
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if (hda == -1) {
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fprintf(stderr, "A disk image must be given for 'hda' when booting "
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"a Linux kernel\n(if you really don't want it, use /dev/zero)\n");
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exit(1);
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}
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memset(rom, 0, sizeof(rom));
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memset(bootsect, 0, sizeof(bootsect));
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p = rom;
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/* Make sure we have an option rom signature */
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*p++ = 0x55;
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*p++ = 0xaa;
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/* Copy the MSDOS partition table if possible */
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bdrv_read(drives_table[hda].bdrv, 0, bootsect, 1);
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/* ROM size in sectors*/
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*p++ = 1;
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/* Make sure we have a partition signature */
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bootsect[510] = 0x55;
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bootsect[511] = 0xaa;
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/* Hook int19 */
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*p++ = 0x50; /* push ax */
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*p++ = 0x1e; /* push ds */
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*p++ = 0x31; *p++ = 0xc0; /* xor ax, ax */
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*p++ = 0x8e; *p++ = 0xd8; /* mov ax, ds */
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*p++ = 0xc7; *p++ = 0x06; /* movvw _start,0x64 */
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*p++ = 0x64; *p++ = 0x00;
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reloc = p;
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*p++ = 0x00; *p++ = 0x00;
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*p++ = 0x8c; *p++ = 0x0e; /* mov cs,0x66 */
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*p++ = 0x66; *p++ = 0x00;
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*p++ = 0x1f; /* pop ds */
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*p++ = 0x58; /* pop ax */
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*p++ = 0xcb; /* lret */
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/* Actual code */
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p = bootsect;
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*reloc = (p - rom);
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*p++ = 0xfa; /* CLI */
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*p++ = 0xfc; /* CLD */
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@ -491,7 +506,13 @@ static void generate_bootsect(uint32_t gpr[8], uint16_t segs[6], uint16_t ip)
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*p++ = segs[1]; /* CS */
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*p++ = segs[1] >> 8;
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bdrv_set_boot_sector(drives_table[hda].bdrv, bootsect, sizeof(bootsect));
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/* sign rom */
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sum = 0;
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for (i = 0; i < (sizeof(rom) - 1); i++)
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sum += rom[i];
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rom[sizeof(rom) - 1] = -sum;
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memcpy(option_rom, rom, sizeof(rom));
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}
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static long get_file_size(FILE *f)
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@ -508,7 +529,8 @@ static long get_file_size(FILE *f)
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return size;
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}
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static void load_linux(const char *kernel_filename,
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static void load_linux(uint8_t *option_rom,
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const char *kernel_filename,
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const char *initrd_filename,
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const char *kernel_cmdline)
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{
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@ -658,7 +680,7 @@ static void load_linux(const char *kernel_filename,
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memset(gpr, 0, sizeof gpr);
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gpr[4] = cmdline_addr-real_addr-16; /* SP (-16 is paranoia) */
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generate_bootsect(gpr, seg, 0);
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generate_bootsect(option_rom, gpr, seg, 0);
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}
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static void main_cpu_reset(void *opaque)
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@ -862,6 +884,15 @@ static void pc_init1(ram_addr_t ram_size, int vga_ram_size,
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int size, offset;
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offset = 0;
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if (linux_boot) {
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option_rom_offset = qemu_ram_alloc(TARGET_PAGE_SIZE);
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load_linux(phys_ram_base + option_rom_offset,
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kernel_filename, initrd_filename, kernel_cmdline);
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cpu_register_physical_memory(0xd0000, TARGET_PAGE_SIZE,
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option_rom_offset | IO_MEM_ROM);
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offset = TARGET_PAGE_SIZE;
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}
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for (i = 0; i < nb_option_roms; i++) {
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size = get_image_size(option_rom[i]);
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if (size < 0) {
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@ -891,9 +922,6 @@ static void pc_init1(ram_addr_t ram_size, int vga_ram_size,
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bochs_bios_init();
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if (linux_boot)
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load_linux(kernel_filename, initrd_filename, kernel_cmdline);
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cpu_irq = qemu_allocate_irqs(pic_irq_request, NULL, 1);
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i8259 = i8259_init(cpu_irq[0]);
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ferr_irq = i8259[13];
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