pc-bios/s390-ccw/bootmap.c

   1 /*
   2  * QEMU S390 bootmap interpreter
   3  *
   4  * Copyright (c) 2009 Alexander Graf <agraf@suse.de>
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or (at
   7  * your option) any later version. See the COPYING file in the top-level
   8  * directory.
   9  */
  10
  11 #include "s390-ccw.h"
  12 #include "bootmap.h"
  13 #include "virtio.h"
  14
  15 #ifdef DEBUG
  16 /* #define DEBUG_FALLBACK */
  17 #endif
  18
  19 #ifdef DEBUG_FALLBACK
  20 #define dputs(txt) \
  21     do { sclp_print("zipl: " txt); } while (0)
  22 #else
  23 #define dputs(fmt, ...) \
  24     do { } while (0)
  25 #endif
  26
  27 /* Scratch space */
  28 static uint8_t sec[MAX_SECTOR_SIZE*4] __attribute__((__aligned__(PAGE_SIZE)));
  29
  30 typedef struct ResetInfo {
  31     uint32_t ipl_mask;
  32     uint32_t ipl_addr;
  33     uint32_t ipl_continue;
  34 } ResetInfo;
  35
  36 static ResetInfo save;
  37
  38 static void jump_to_IPL_2(void)
  39 {
  40     ResetInfo *current = 0;
  41
  42     void (*ipl)(void) = (void *) (uint64_t) current->ipl_continue;
  43     *current = save;
  44     ipl(); /* should not return */
  45 }
  46
  47 static void jump_to_IPL_code(uint64_t address)
  48 {
  49     /* store the subsystem information _after_ the bootmap was loaded */
  50     write_subsystem_identification();
  51     /*
  52      * The IPL PSW is at address 0. We also must not overwrite the
  53      * content of non-BIOS memory after we loaded the guest, so we
  54      * save the original content and restore it in jump_to_IPL_2.
  55      */
  56     ResetInfo *current = 0;
  57
  58     save = *current;
  59     current->ipl_addr = (uint32_t) (uint64_t) &jump_to_IPL_2;
  60     current->ipl_continue = address & 0x7fffffff;
  61
  62     debug_print_int("set IPL addr to", current->ipl_continue);
  63
  64     /* Ensure the guest output starts fresh */
  65     sclp_print("\n");
  66
  67     /*
  68      * HACK ALERT.
  69      * We use the load normal reset to keep r15 unchanged. jump_to_IPL_2
  70      * can then use r15 as its stack pointer.
  71      */
  72     asm volatile("lghi 1,1\n\t"
  73                  "diag 1,1,0x308\n\t"
  74                  : : : "1", "memory");
  75     panic("\n! IPL returns !\n");
  76 }
  77
  78 /***********************************************************************
  79  * IPL an ECKD DASD (CDL or LDL/CMS format)
  80  */
  81
  82 static unsigned char _bprs[8*1024]; /* guessed "max" ECKD sector size */
  83 static const int max_bprs_entries = sizeof(_bprs) / sizeof(ExtEckdBlockPtr);
  84
  85 static inline void verify_boot_info(BootInfo *bip)
  86 {
  87     IPL_assert(magic_match(bip->magic, ZIPL_MAGIC), "No zIPL sig in BootInfo");
  88     IPL_assert(bip->version == BOOT_INFO_VERSION, "Wrong zIPL version");
  89     IPL_assert(bip->bp_type == BOOT_INFO_BP_TYPE_IPL, "DASD is not for IPL");
  90     IPL_assert(bip->dev_type == BOOT_INFO_DEV_TYPE_ECKD, "DASD is not ECKD");
  91     IPL_assert(bip->flags == BOOT_INFO_FLAGS_ARCH, "Not for this arch");
  92     IPL_assert(block_size_ok(bip->bp.ipl.bm_ptr.eckd.bptr.size),
  93                "Bad block size in zIPL section of the 1st record.");
  94 }
  95
  96 static block_number_t eckd_block_num(BootMapPointer *p)
  97 {
  98     const uint64_t sectors = virtio_get_sectors();
  99     const uint64_t heads = virtio_get_heads();
 100     const uint64_t cylinder = p->eckd.cylinder
 101                             + ((p->eckd.head & 0xfff0) << 12);
 102     const uint64_t head = p->eckd.head & 0x000f;
 103     const block_number_t block = sectors * heads * cylinder
 104                                + sectors * head
 105                                + p->eckd.sector
 106                                - 1; /* block nr starts with zero */
 107     return block;
 108 }
 109
 110 static bool eckd_valid_address(BootMapPointer *p)
 111 {
 112     const uint64_t head = p->eckd.head & 0x000f;
 113
 114     if (head >= virtio_get_heads()
 115         ||  p->eckd.sector > virtio_get_sectors()
 116         ||  p->eckd.sector <= 0) {
 117         return false;
 118     }
 119
 120     if (!virtio_guessed_disk_nature() &&
 121         eckd_block_num(p) >= virtio_get_blocks()) {
 122         return false;
 123     }
 124
 125     return true;
 126 }
 127
 128 static block_number_t load_eckd_segments(block_number_t blk, uint64_t *address)
 129 {
 130     block_number_t block_nr;
 131     int j, rc;
 132     BootMapPointer *bprs = (void *)_bprs;
 133     bool more_data;
 134
 135     memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
 136     read_block(blk, bprs, "BPRS read failed");
 137
 138     do {
 139         more_data = false;
 140         for (j = 0;; j++) {
 141             block_nr = eckd_block_num((void *)&(bprs[j].xeckd));
 142             if (is_null_block_number(block_nr)) { /* end of chunk */
 143                 break;
 144             }
 145
 146             /* we need the updated blockno for the next indirect entry
 147              * in the chain, but don't want to advance address
 148              */
 149             if (j == (max_bprs_entries - 1)) {
 150                 break;
 151             }
 152
 153             IPL_assert(block_size_ok(bprs[j].xeckd.bptr.size),
 154                        "bad chunk block size");
 155             IPL_assert(eckd_valid_address(&bprs[j]), "bad chunk ECKD addr");
 156
 157             if ((bprs[j].xeckd.bptr.count == 0) && unused_space(&(bprs[j+1]),
 158                 sizeof(EckdBlockPtr))) {
 159                 /* This is a "continue" pointer.
 160                  * This ptr should be the last one in the current
 161                  * script section.
 162                  * I.e. the next ptr must point to the unused memory area
 163                  */
 164                 memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
 165                 read_block(block_nr, bprs, "BPRS continuation read failed");
 166                 more_data = true;
 167                 break;
 168             }
 169
 170             /* Load (count+1) blocks of code at (block_nr)
 171              * to memory (address).
 172              */
 173             rc = virtio_read_many(block_nr, (void *)(*address),
 174                                   bprs[j].xeckd.bptr.count+1);
 175             IPL_assert(rc == 0, "code chunk read failed");
 176
 177             *address += (bprs[j].xeckd.bptr.count+1) * virtio_get_block_size();
 178         }
 179     } while (more_data);
 180     return block_nr;
 181 }
 182
 183 static void run_eckd_boot_script(block_number_t mbr_block_nr)
 184 {
 185     int i;
 186     unsigned int loadparm = get_loadparm_index();
 187     block_number_t block_nr;
 188     uint64_t address;
 189     ScsiMbr *bte = (void *)sec; /* Eckd bootmap table entry */
 190     BootMapScript *bms = (void *)sec;
 191
 192     debug_print_int("loadparm", loadparm);
 193     IPL_assert(loadparm < 31, "loadparm value greater than"
 194                " maximum number of boot entries allowed");
 195
 196     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 197     read_block(mbr_block_nr, sec, "Cannot read MBR");
 198
 199     block_nr = eckd_block_num((void *)&(bte->blockptr[loadparm]));
 200     IPL_assert(block_nr != -1, "No Boot Map");
 201
 202     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 203     read_block(block_nr, sec, "Cannot read Boot Map Script");
 204
 205     for (i = 0; bms->entry[i].type == BOOT_SCRIPT_LOAD; i++) {
 206         address = bms->entry[i].address.load_address;
 207         block_nr = eckd_block_num(&(bms->entry[i].blkptr));
 208
 209         do {
 210             block_nr = load_eckd_segments(block_nr, &address);
 211         } while (block_nr != -1);
 212     }
 213
 214     IPL_assert(bms->entry[i].type == BOOT_SCRIPT_EXEC,
 215                "Unknown script entry type");
 216     jump_to_IPL_code(bms->entry[i].address.load_address); /* no return */
 217 }
 218
 219 static void ipl_eckd_cdl(void)
 220 {
 221     XEckdMbr *mbr;
 222     Ipl2 *ipl2 = (void *)sec;
 223     IplVolumeLabel *vlbl = (void *)sec;
 224     block_number_t block_nr;
 225
 226     /* we have just read the block #0 and recognized it as "IPL1" */
 227     sclp_print("CDL\n");
 228
 229     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 230     read_block(1, ipl2, "Cannot read IPL2 record at block 1");
 231
 232     mbr = &ipl2->u.x.mbr;
 233     IPL_assert(magic_match(mbr, ZIPL_MAGIC), "No zIPL section in IPL2 record.");
 234     IPL_assert(block_size_ok(mbr->blockptr.xeckd.bptr.size),
 235                "Bad block size in zIPL section of IPL2 record.");
 236     IPL_assert(mbr->dev_type == DEV_TYPE_ECKD,
 237                "Non-ECKD device type in zIPL section of IPL2 record.");
 238
 239     /* save pointer to Boot Script */
 240     block_nr = eckd_block_num((void *)&(mbr->blockptr));
 241
 242     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 243     read_block(2, vlbl, "Cannot read Volume Label at block 2");
 244     IPL_assert(magic_match(vlbl->key, VOL1_MAGIC),
 245                "Invalid magic of volume label block");
 246     IPL_assert(magic_match(vlbl->f.key, VOL1_MAGIC),
 247                "Invalid magic of volser block");
 248     print_volser(vlbl->f.volser);
 249
 250     run_eckd_boot_script(block_nr);
 251     /* no return */
 252 }
 253
 254 static void print_eckd_ldl_msg(ECKD_IPL_mode_t mode)
 255 {
 256     LDL_VTOC *vlbl = (void *)sec; /* already read, 3rd block */
 257     char msg[4] = { '?', '.', '\n', '\0' };
 258
 259     sclp_print((mode == ECKD_CMS) ? "CMS" : "LDL");
 260     sclp_print(" version ");
 261     switch (vlbl->LDL_version) {
 262     case LDL1_VERSION:
 263         msg[0] = '1';
 264         break;
 265     case LDL2_VERSION:
 266         msg[0] = '2';
 267         break;
 268     default:
 269         msg[0] = vlbl->LDL_version;
 270         msg[0] &= 0x0f; /* convert EBCDIC   */
 271         msg[0] |= 0x30; /* to ASCII (digit) */
 272         msg[1] = '?';
 273         break;
 274     }
 275     sclp_print(msg);
 276     print_volser(vlbl->volser);
 277 }
 278
 279 static void ipl_eckd_ldl(ECKD_IPL_mode_t mode)
 280 {
 281     block_number_t block_nr;
 282     BootInfo *bip = (void *)(sec + 0x70); /* BootInfo is MBR for LDL */
 283
 284     if (mode != ECKD_LDL_UNLABELED) {
 285         print_eckd_ldl_msg(mode);
 286     }
 287
 288     /* DO NOT read BootMap pointer (only one, xECKD) at block #2 */
 289
 290     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 291     read_block(0, sec, "Cannot read block 0 to grab boot info.");
 292     if (mode == ECKD_LDL_UNLABELED) {
 293         if (!magic_match(bip->magic, ZIPL_MAGIC)) {
 294             return; /* not applicable layout */
 295         }
 296         sclp_print("unlabeled LDL.\n");
 297     }
 298     verify_boot_info(bip);
 299
 300     block_nr = eckd_block_num((void *)&(bip->bp.ipl.bm_ptr.eckd.bptr));
 301     run_eckd_boot_script(block_nr);
 302     /* no return */
 303 }
 304
 305 static void print_eckd_msg(void)
 306 {
 307     char msg[] = "Using ECKD scheme (block size *****), ";
 308     char *p = &msg[34], *q = &msg[30];
 309     int n = virtio_get_block_size();
 310
 311     /* Fill in the block size and show up the message */
 312     if (n > 0 && n <= 99999) {
 313         while (n) {
 314             *p-- = '0' + (n % 10);
 315             n /= 10;
 316         }
 317         while (p >= q) {
 318             *p-- = ' ';
 319         }
 320     }
 321     sclp_print(msg);
 322 }
 323
 324 static void ipl_eckd(void)
 325 {
 326     ScsiMbr *mbr = (void *)sec;
 327     LDL_VTOC *vlbl = (void *)sec;
 328
 329     print_eckd_msg();
 330
 331     /* Grab the MBR again */
 332     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 333     read_block(0, mbr, "Cannot read block 0 on DASD");
 334
 335     if (magic_match(mbr->magic, IPL1_MAGIC)) {
 336         ipl_eckd_cdl(); /* no return */
 337     }
 338
 339     /* LDL/CMS? */
 340     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 341     read_block(2, vlbl, "Cannot read block 2");
 342
 343     if (magic_match(vlbl->magic, CMS1_MAGIC)) {
 344         ipl_eckd_ldl(ECKD_CMS); /* no return */
 345     }
 346     if (magic_match(vlbl->magic, LNX1_MAGIC)) {
 347         ipl_eckd_ldl(ECKD_LDL); /* no return */
 348     }
 349
 350     ipl_eckd_ldl(ECKD_LDL_UNLABELED); /* it still may return */
 351     /*
 352      * Ok, it is not a LDL by any means.
 353      * It still might be a CDL with zero record keys for IPL1 and IPL2
 354      */
 355     ipl_eckd_cdl();
 356 }
 357
 358 /***********************************************************************
 359  * IPL a SCSI disk
 360  */
 361
 362 static void zipl_load_segment(ComponentEntry *entry)
 363 {
 364     const int max_entries = (MAX_SECTOR_SIZE / sizeof(ScsiBlockPtr));
 365     ScsiBlockPtr *bprs = (void *)sec;
 366     const int bprs_size = sizeof(sec);
 367     block_number_t blockno;
 368     uint64_t address;
 369     int i;
 370     char err_msg[] = "zIPL failed to read BPRS at 0xZZZZZZZZZZZZZZZZ";
 371     char *blk_no = &err_msg[30]; /* where to print blockno in (those ZZs) */
 372
 373     blockno = entry->data.blockno;
 374     address = entry->load_address;
 375
 376     debug_print_int("loading segment at block", blockno);
 377     debug_print_int("addr", address);
 378
 379     do {
 380         memset(bprs, FREE_SPACE_FILLER, bprs_size);
 381         fill_hex_val(blk_no, &blockno, sizeof(blockno));
 382         read_block(blockno, bprs, err_msg);
 383
 384         for (i = 0;; i++) {
 385             uint64_t *cur_desc = (void *)&bprs[i];
 386
 387             blockno = bprs[i].blockno;
 388             if (!blockno) {
 389                 break;
 390             }
 391
 392             /* we need the updated blockno for the next indirect entry in the
 393                chain, but don't want to advance address */
 394             if (i == (max_entries - 1)) {
 395                 break;
 396             }
 397
 398             if (bprs[i].blockct == 0 && unused_space(&bprs[i + 1],
 399                 sizeof(ScsiBlockPtr))) {
 400                 /* This is a "continue" pointer.
 401                  * This ptr is the last one in the current script section.
 402                  * I.e. the next ptr must point to the unused memory area.
 403                  * The blockno is not zero, so the upper loop must continue
 404                  * reading next section of BPRS.
 405                  */
 406                 break;
 407             }
 408             address = virtio_load_direct(cur_desc[0], cur_desc[1], 0,
 409                                          (void *)address);
 410             IPL_assert(address != -1, "zIPL load segment failed");
 411         }
 412     } while (blockno);
 413 }
 414
 415 /* Run a zipl program */
 416 static void zipl_run(ScsiBlockPtr *pte)
 417 {
 418     ComponentHeader *header;
 419     ComponentEntry *entry;
 420     uint8_t tmp_sec[MAX_SECTOR_SIZE];
 421
 422     read_block(pte->blockno, tmp_sec, "Cannot read header");
 423     header = (ComponentHeader *)tmp_sec;
 424
 425     IPL_assert(magic_match(tmp_sec, ZIPL_MAGIC), "No zIPL magic in header");
 426     IPL_assert(header->type == ZIPL_COMP_HEADER_IPL, "Bad header type");
 427
 428     dputs("start loading images\n");
 429
 430     /* Load image(s) into RAM */
 431     entry = (ComponentEntry *)(&header[1]);
 432     while (entry->component_type == ZIPL_COMP_ENTRY_LOAD) {
 433         zipl_load_segment(entry);
 434
 435         entry++;
 436
 437         IPL_assert((uint8_t *)(&entry[1]) <= (tmp_sec + MAX_SECTOR_SIZE),
 438                    "Wrong entry value");
 439     }
 440
 441     IPL_assert(entry->component_type == ZIPL_COMP_ENTRY_EXEC, "No EXEC entry");
 442
 443     /* should not return */
 444     jump_to_IPL_code(entry->load_address);
 445 }
 446
 447 static void ipl_scsi(void)
 448 {
 449     ScsiMbr *mbr = (void *)sec;
 450     uint8_t *ns, *ns_end;
 451     int program_table_entries = 0;
 452     const int pte_len = sizeof(ScsiBlockPtr);
 453     ScsiBlockPtr *prog_table_entry = NULL;
 454     unsigned int loadparm = get_loadparm_index();
 455
 456     /* Grab the MBR */
 457     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 458     read_block(0, mbr, "Cannot read block 0");
 459
 460     if (!magic_match(mbr->magic, ZIPL_MAGIC)) {
 461         return;
 462     }
 463
 464     sclp_print("Using SCSI scheme.\n");
 465     debug_print_int("MBR Version", mbr->version_id);
 466     IPL_check(mbr->version_id == 1,
 467               "Unknown MBR layout version, assuming version 1");
 468     debug_print_int("program table", mbr->blockptr[0].blockno);
 469     IPL_assert(mbr->blockptr[0].blockno, "No Program Table");
 470
 471     /* Parse the program table */
 472     read_block(mbr->blockptr[0].blockno, sec,
 473                "Error reading Program Table");
 474
 475     IPL_assert(magic_match(sec, ZIPL_MAGIC), "No zIPL magic in PT");
 476
 477     debug_print_int("loadparm index", loadparm);
 478     ns_end = sec + virtio_get_block_size();
 479     for (ns = (sec + pte_len); (ns + pte_len) < ns_end; ns += pte_len) {
 480         prog_table_entry = (ScsiBlockPtr *)ns;
 481         if (!prog_table_entry->blockno) {
 482             break;
 483         }
 484
 485         program_table_entries++;
 486         if (program_table_entries == loadparm + 1) {
 487             break; /* selected entry found */
 488         }
 489     }
 490
 491     debug_print_int("program table entries", program_table_entries);
 492
 493     IPL_assert(program_table_entries != 0, "Empty Program Table");
 494
 495     zipl_run(prog_table_entry); /* no return */
 496 }
 497
 498 /***********************************************************************
 499  * IPL El Torito ISO9660 image or DVD
 500  */
 501
 502 static bool is_iso_bc_entry_compatible(IsoBcSection *s)
 503 {
 504     uint8_t *magic_sec = (uint8_t *)(sec + ISO_SECTOR_SIZE);
 505
 506     if (s->unused || !s->sector_count) {
 507         return false;
 508     }
 509     read_iso_sector(bswap32(s->load_rba), magic_sec,
 510                     "Failed to read image sector 0");
 511
 512     /* Checking bytes 8 - 32 for S390 Linux magic */
 513     return !_memcmp(magic_sec + 8, linux_s390_magic, 24);
 514 }
 515
 516 /* Location of the current sector of the directory */
 517 static uint32_t sec_loc[ISO9660_MAX_DIR_DEPTH];
 518 /* Offset in the current sector of the directory */
 519 static uint32_t sec_offset[ISO9660_MAX_DIR_DEPTH];
 520 /* Remained directory space in bytes */
 521 static uint32_t dir_rem[ISO9660_MAX_DIR_DEPTH];
 522
 523 static inline uint32_t iso_get_file_size(uint32_t load_rba)
 524 {
 525     IsoVolDesc *vd = (IsoVolDesc *)sec;
 526     IsoDirHdr *cur_record = &vd->vd.primary.rootdir;
 527     uint8_t *temp = sec + ISO_SECTOR_SIZE;
 528     int level = 0;
 529
 530     read_iso_sector(ISO_PRIMARY_VD_SECTOR, sec,
 531                     "Failed to read ISO primary descriptor");
 532     sec_loc[0] = iso_733_to_u32(cur_record->ext_loc);
 533     dir_rem[0] = 0;
 534     sec_offset[0] = 0;
 535
 536     while (level >= 0) {
 537         IPL_assert(sec_offset[level] <= ISO_SECTOR_SIZE,
 538                    "Directory tree structure violation");
 539
 540         cur_record = (IsoDirHdr *)(temp + sec_offset[level]);
 541
 542         if (sec_offset[level] == 0) {
 543             read_iso_sector(sec_loc[level], temp,
 544                             "Failed to read ISO directory");
 545             if (dir_rem[level] == 0) {
 546                 /* Skip self and parent records */
 547                 dir_rem[level] = iso_733_to_u32(cur_record->data_len) -
 548                                  cur_record->dr_len;
 549                 sec_offset[level] += cur_record->dr_len;
 550
 551                 cur_record = (IsoDirHdr *)(temp + sec_offset[level]);
 552                 dir_rem[level] -= cur_record->dr_len;
 553                 sec_offset[level] += cur_record->dr_len;
 554                 continue;
 555             }
 556         }
 557
 558         if (!cur_record->dr_len || sec_offset[level] == ISO_SECTOR_SIZE) {
 559             /* Zero-padding and/or the end of current sector */
 560             dir_rem[level] -= ISO_SECTOR_SIZE - sec_offset[level];
 561             sec_offset[level] = 0;
 562             sec_loc[level]++;
 563         } else {
 564             /* The directory record is valid */
 565             if (load_rba == iso_733_to_u32(cur_record->ext_loc)) {
 566                 return iso_733_to_u32(cur_record->data_len);
 567             }
 568
 569             dir_rem[level] -= cur_record->dr_len;
 570             sec_offset[level] += cur_record->dr_len;
 571
 572             if (cur_record->file_flags & 0x2) {
 573                 /* Subdirectory */
 574                 if (level == ISO9660_MAX_DIR_DEPTH - 1) {
 575                     sclp_print("ISO-9660 directory depth limit exceeded\n");
 576                 } else {
 577                     level++;
 578                     sec_loc[level] = iso_733_to_u32(cur_record->ext_loc);
 579                     sec_offset[level] = 0;
 580                     dir_rem[level] = 0;
 581                     continue;
 582                 }
 583             }
 584         }
 585
 586         if (dir_rem[level] == 0) {
 587             /* Nothing remaining */
 588             level--;
 589             read_iso_sector(sec_loc[level], temp,
 590                             "Failed to read ISO directory");
 591         }
 592     }
 593
 594     return 0;
 595 }
 596
 597 static void load_iso_bc_entry(IsoBcSection *load)
 598 {
 599     IsoBcSection s = *load;
 600     /*
 601      * According to spec, extent for each file
 602      * is padded and ISO_SECTOR_SIZE bytes aligned
 603      */
 604     uint32_t blks_to_load = bswap16(s.sector_count) >> ET_SECTOR_SHIFT;
 605     uint32_t real_size = iso_get_file_size(bswap32(s.load_rba));
 606
 607     if (real_size) {
 608         /* Round up blocks to load */
 609         blks_to_load = (real_size + ISO_SECTOR_SIZE - 1) / ISO_SECTOR_SIZE;
 610         sclp_print("ISO boot image size verified\n");
 611     } else {
 612         sclp_print("ISO boot image size could not be verified\n");
 613     }
 614
 615     read_iso_boot_image(bswap32(s.load_rba),
 616                         (void *)((uint64_t)bswap16(s.load_segment)),
 617                         blks_to_load);
 618
 619     /* Trying to get PSW at zero address */
 620     if (*((uint64_t *)0) & IPL_PSW_MASK) {
 621         jump_to_IPL_code((*((uint64_t *)0)) & 0x7fffffff);
 622     }
 623
 624     /* Try default linux start address */
 625     jump_to_IPL_code(KERN_IMAGE_START);
 626 }
 627
 628 static uint32_t find_iso_bc(void)
 629 {
 630     IsoVolDesc *vd = (IsoVolDesc *)sec;
 631     uint32_t block_num = ISO_PRIMARY_VD_SECTOR;
 632
 633     if (virtio_read_many(block_num++, sec, 1)) {
 634         /* If primary vd cannot be read, there is no boot catalog */
 635         return 0;
 636     }
 637
 638     while (is_iso_vd_valid(vd) && vd->type != VOL_DESC_TERMINATOR) {
 639         if (vd->type == VOL_DESC_TYPE_BOOT) {
 640             IsoVdElTorito *et = &vd->vd.boot;
 641
 642             if (!_memcmp(&et->el_torito[0], el_torito_magic, 32)) {
 643                 return bswap32(et->bc_offset);
 644             }
 645         }
 646         read_iso_sector(block_num++, sec,
 647                         "Failed to read ISO volume descriptor");
 648     }
 649
 650     return 0;
 651 }
 652
 653 static IsoBcSection *find_iso_bc_entry(void)
 654 {
 655     IsoBcEntry *e = (IsoBcEntry *)sec;
 656     uint32_t offset = find_iso_bc();
 657     int i;
 658     unsigned int loadparm = get_loadparm_index();
 659
 660     if (!offset) {
 661         return NULL;
 662     }
 663
 664     read_iso_sector(offset, sec, "Failed to read El Torito boot catalog");
 665
 666     if (!is_iso_bc_valid(e)) {
 667         /* The validation entry is mandatory */
 668         panic("No valid boot catalog found!\n");
 669         return NULL;
 670     }
 671
 672     /*
 673      * Each entry has 32 bytes size, so one sector cannot contain > 64 entries.
 674      * We consider only boot catalogs with no more than 64 entries.
 675      */
 676     for (i = 1; i < ISO_BC_ENTRY_PER_SECTOR; i++) {
 677         if (e[i].id == ISO_BC_BOOTABLE_SECTION) {
 678             if (is_iso_bc_entry_compatible(&e[i].body.sect)) {
 679                 if (loadparm <= 1) {
 680                     /* found, default, or unspecified */
 681                     return &e[i].body.sect;
 682                 }
 683                 loadparm--;
 684             }
 685         }
 686     }
 687
 688     panic("No suitable boot entry found on ISO-9660 media!\n");
 689
 690     return NULL;
 691 }
 692
 693 static void ipl_iso_el_torito(void)
 694 {
 695     IsoBcSection *s = find_iso_bc_entry();
 696
 697     if (s) {
 698         load_iso_bc_entry(s);
 699         /* no return */
 700     }
 701 }
 702
 703 /***********************************************************************
 704  * Bus specific IPL sequences
 705  */
 706
 707 static void zipl_load_vblk(void)
 708 {
 709     if (virtio_guessed_disk_nature()) {
 710         virtio_assume_iso9660();
 711     }
 712     ipl_iso_el_torito();
 713
 714     if (virtio_guessed_disk_nature()) {
 715         sclp_print("Using guessed DASD geometry.\n");
 716         virtio_assume_eckd();
 717     }
 718     ipl_eckd();
 719 }
 720
 721 static void zipl_load_vscsi(void)
 722 {
 723     if (virtio_get_block_size() == VIRTIO_ISO_BLOCK_SIZE) {
 724         /* Is it an ISO image in non-CD drive? */
 725         ipl_iso_el_torito();
 726     }
 727
 728     sclp_print("Using guessed DASD geometry.\n");
 729     virtio_assume_eckd();
 730     ipl_eckd();
 731 }
 732
 733 /***********************************************************************
 734  * IPL starts here
 735  */
 736
 737 void zipl_load(void)
 738 {
 739     VDev *vdev = virtio_get_device();
 740
 741     if (vdev->is_cdrom) {
 742         ipl_iso_el_torito();
 743         panic("\n! Cannot IPL this ISO image !\n");
 744     }
 745
 746     if (virtio_get_device_type() == VIRTIO_ID_NET) {
 747         jump_to_IPL_code(vdev->netboot_start_addr);
 748     }
 749
 750     ipl_scsi();
 751
 752     switch (virtio_get_device_type()) {
 753     case VIRTIO_ID_BLOCK:
 754         zipl_load_vblk();
 755         break;
 756     case VIRTIO_ID_SCSI:
 757         zipl_load_vscsi();
 758         break;
 759     default:
 760         panic("\n! Unknown IPL device type !\n");
 761     }
 762
 763     panic("\n* this can never happen *\n");
 764 }