dump.c

   1 /*
   2  * QEMU dump
   3  *
   4  * Copyright Fujitsu, Corp. 2011, 2012
   5  *
   6  * Authors:
   7  *     Wen Congyang <wency@cn.fujitsu.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qemu-common.h"
  15 #include "elf.h"
  16 #include "cpu.h"
  17 #include "exec/cpu-all.h"
  18 #include "exec/hwaddr.h"
  19 #include "monitor/monitor.h"
  20 #include "sysemu/kvm.h"
  21 #include "sysemu/dump.h"
  22 #include "sysemu/sysemu.h"
  23 #include "sysemu/memory_mapping.h"
  24 #include "sysemu/cpus.h"
  25 #include "qapi/error.h"
  26 #include "qmp-commands.h"
  27
  28 static uint16_t cpu_convert_to_target16(uint16_t val, int endian)
  29 {
  30     if (endian == ELFDATA2LSB) {
  31         val = cpu_to_le16(val);
  32     } else {
  33         val = cpu_to_be16(val);
  34     }
  35
  36     return val;
  37 }
  38
  39 static uint32_t cpu_convert_to_target32(uint32_t val, int endian)
  40 {
  41     if (endian == ELFDATA2LSB) {
  42         val = cpu_to_le32(val);
  43     } else {
  44         val = cpu_to_be32(val);
  45     }
  46
  47     return val;
  48 }
  49
  50 static uint64_t cpu_convert_to_target64(uint64_t val, int endian)
  51 {
  52     if (endian == ELFDATA2LSB) {
  53         val = cpu_to_le64(val);
  54     } else {
  55         val = cpu_to_be64(val);
  56     }
  57
  58     return val;
  59 }
  60
  61 typedef struct DumpState {
  62     GuestPhysBlockList guest_phys_blocks;
  63     ArchDumpInfo dump_info;
  64     MemoryMappingList list;
  65     uint16_t phdr_num;
  66     uint32_t sh_info;
  67     bool have_section;
  68     bool resume;
  69     size_t note_size;
  70     hwaddr memory_offset;
  71     int fd;
  72
  73     GuestPhysBlock *next_block;
  74     ram_addr_t start;
  75     bool has_filter;
  76     int64_t begin;
  77     int64_t length;
  78     Error **errp;
  79 } DumpState;
  80
  81 static int dump_cleanup(DumpState *s)
  82 {
  83     int ret = 0;
  84
  85     guest_phys_blocks_free(&s->guest_phys_blocks);
  86     memory_mapping_list_free(&s->list);
  87     if (s->fd != -1) {
  88         close(s->fd);
  89     }
  90     if (s->resume) {
  91         vm_start();
  92     }
  93
  94     return ret;
  95 }
  96
  97 static void dump_error(DumpState *s, const char *reason)
  98 {
  99     dump_cleanup(s);
 100 }
 101
 102 static int fd_write_vmcore(void *buf, size_t size, void *opaque)
 103 {
 104     DumpState *s = opaque;
 105     size_t written_size;
 106
 107     written_size = qemu_write_full(s->fd, buf, size);
 108     if (written_size != size) {
 109         return -1;
 110     }
 111
 112     return 0;
 113 }
 114
 115 static int write_elf64_header(DumpState *s)
 116 {
 117     Elf64_Ehdr elf_header;
 118     int ret;
 119     int endian = s->dump_info.d_endian;
 120
 121     memset(&elf_header, 0, sizeof(Elf64_Ehdr));
 122     memcpy(&elf_header, ELFMAG, SELFMAG);
 123     elf_header.e_ident[EI_CLASS] = ELFCLASS64;
 124     elf_header.e_ident[EI_DATA] = s->dump_info.d_endian;
 125     elf_header.e_ident[EI_VERSION] = EV_CURRENT;
 126     elf_header.e_type = cpu_convert_to_target16(ET_CORE, endian);
 127     elf_header.e_machine = cpu_convert_to_target16(s->dump_info.d_machine,
 128                                                    endian);
 129     elf_header.e_version = cpu_convert_to_target32(EV_CURRENT, endian);
 130     elf_header.e_ehsize = cpu_convert_to_target16(sizeof(elf_header), endian);
 131     elf_header.e_phoff = cpu_convert_to_target64(sizeof(Elf64_Ehdr), endian);
 132     elf_header.e_phentsize = cpu_convert_to_target16(sizeof(Elf64_Phdr),
 133                                                      endian);
 134     elf_header.e_phnum = cpu_convert_to_target16(s->phdr_num, endian);
 135     if (s->have_section) {
 136         uint64_t shoff = sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr) * s->sh_info;
 137
 138         elf_header.e_shoff = cpu_convert_to_target64(shoff, endian);
 139         elf_header.e_shentsize = cpu_convert_to_target16(sizeof(Elf64_Shdr),
 140                                                          endian);
 141         elf_header.e_shnum = cpu_convert_to_target16(1, endian);
 142     }
 143
 144     ret = fd_write_vmcore(&elf_header, sizeof(elf_header), s);
 145     if (ret < 0) {
 146         dump_error(s, "dump: failed to write elf header.\n");
 147         return -1;
 148     }
 149
 150     return 0;
 151 }
 152
 153 static int write_elf32_header(DumpState *s)
 154 {
 155     Elf32_Ehdr elf_header;
 156     int ret;
 157     int endian = s->dump_info.d_endian;
 158
 159     memset(&elf_header, 0, sizeof(Elf32_Ehdr));
 160     memcpy(&elf_header, ELFMAG, SELFMAG);
 161     elf_header.e_ident[EI_CLASS] = ELFCLASS32;
 162     elf_header.e_ident[EI_DATA] = endian;
 163     elf_header.e_ident[EI_VERSION] = EV_CURRENT;
 164     elf_header.e_type = cpu_convert_to_target16(ET_CORE, endian);
 165     elf_header.e_machine = cpu_convert_to_target16(s->dump_info.d_machine,
 166                                                    endian);
 167     elf_header.e_version = cpu_convert_to_target32(EV_CURRENT, endian);
 168     elf_header.e_ehsize = cpu_convert_to_target16(sizeof(elf_header), endian);
 169     elf_header.e_phoff = cpu_convert_to_target32(sizeof(Elf32_Ehdr), endian);
 170     elf_header.e_phentsize = cpu_convert_to_target16(sizeof(Elf32_Phdr),
 171                                                      endian);
 172     elf_header.e_phnum = cpu_convert_to_target16(s->phdr_num, endian);
 173     if (s->have_section) {
 174         uint32_t shoff = sizeof(Elf32_Ehdr) + sizeof(Elf32_Phdr) * s->sh_info;
 175
 176         elf_header.e_shoff = cpu_convert_to_target32(shoff, endian);
 177         elf_header.e_shentsize = cpu_convert_to_target16(sizeof(Elf32_Shdr),
 178                                                          endian);
 179         elf_header.e_shnum = cpu_convert_to_target16(1, endian);
 180     }
 181
 182     ret = fd_write_vmcore(&elf_header, sizeof(elf_header), s);
 183     if (ret < 0) {
 184         dump_error(s, "dump: failed to write elf header.\n");
 185         return -1;
 186     }
 187
 188     return 0;
 189 }
 190
 191 static int write_elf64_load(DumpState *s, MemoryMapping *memory_mapping,
 192                             int phdr_index, hwaddr offset,
 193                             hwaddr filesz)
 194 {
 195     Elf64_Phdr phdr;
 196     int ret;
 197     int endian = s->dump_info.d_endian;
 198
 199     memset(&phdr, 0, sizeof(Elf64_Phdr));
 200     phdr.p_type = cpu_convert_to_target32(PT_LOAD, endian);
 201     phdr.p_offset = cpu_convert_to_target64(offset, endian);
 202     phdr.p_paddr = cpu_convert_to_target64(memory_mapping->phys_addr, endian);
 203     phdr.p_filesz = cpu_convert_to_target64(filesz, endian);
 204     phdr.p_memsz = cpu_convert_to_target64(memory_mapping->length, endian);
 205     phdr.p_vaddr = cpu_convert_to_target64(memory_mapping->virt_addr, endian);
 206
 207     assert(memory_mapping->length >= filesz);
 208
 209     ret = fd_write_vmcore(&phdr, sizeof(Elf64_Phdr), s);
 210     if (ret < 0) {
 211         dump_error(s, "dump: failed to write program header table.\n");
 212         return -1;
 213     }
 214
 215     return 0;
 216 }
 217
 218 static int write_elf32_load(DumpState *s, MemoryMapping *memory_mapping,
 219                             int phdr_index, hwaddr offset,
 220                             hwaddr filesz)
 221 {
 222     Elf32_Phdr phdr;
 223     int ret;
 224     int endian = s->dump_info.d_endian;
 225
 226     memset(&phdr, 0, sizeof(Elf32_Phdr));
 227     phdr.p_type = cpu_convert_to_target32(PT_LOAD, endian);
 228     phdr.p_offset = cpu_convert_to_target32(offset, endian);
 229     phdr.p_paddr = cpu_convert_to_target32(memory_mapping->phys_addr, endian);
 230     phdr.p_filesz = cpu_convert_to_target32(filesz, endian);
 231     phdr.p_memsz = cpu_convert_to_target32(memory_mapping->length, endian);
 232     phdr.p_vaddr = cpu_convert_to_target32(memory_mapping->virt_addr, endian);
 233
 234     assert(memory_mapping->length >= filesz);
 235
 236     ret = fd_write_vmcore(&phdr, sizeof(Elf32_Phdr), s);
 237     if (ret < 0) {
 238         dump_error(s, "dump: failed to write program header table.\n");
 239         return -1;
 240     }
 241
 242     return 0;
 243 }
 244
 245 static int write_elf64_note(DumpState *s)
 246 {
 247     Elf64_Phdr phdr;
 248     int endian = s->dump_info.d_endian;
 249     hwaddr begin = s->memory_offset - s->note_size;
 250     int ret;
 251
 252     memset(&phdr, 0, sizeof(Elf64_Phdr));
 253     phdr.p_type = cpu_convert_to_target32(PT_NOTE, endian);
 254     phdr.p_offset = cpu_convert_to_target64(begin, endian);
 255     phdr.p_paddr = 0;
 256     phdr.p_filesz = cpu_convert_to_target64(s->note_size, endian);
 257     phdr.p_memsz = cpu_convert_to_target64(s->note_size, endian);
 258     phdr.p_vaddr = 0;
 259
 260     ret = fd_write_vmcore(&phdr, sizeof(Elf64_Phdr), s);
 261     if (ret < 0) {
 262         dump_error(s, "dump: failed to write program header table.\n");
 263         return -1;
 264     }
 265
 266     return 0;
 267 }
 268
 269 static inline int cpu_index(CPUState *cpu)
 270 {
 271     return cpu->cpu_index + 1;
 272 }
 273
 274 static int write_elf64_notes(DumpState *s)
 275 {
 276     CPUState *cpu;
 277     int ret;
 278     int id;
 279
 280     CPU_FOREACH(cpu) {
 281         id = cpu_index(cpu);
 282         ret = cpu_write_elf64_note(fd_write_vmcore, cpu, id, s);
 283         if (ret < 0) {
 284             dump_error(s, "dump: failed to write elf notes.\n");
 285             return -1;
 286         }
 287     }
 288
 289     CPU_FOREACH(cpu) {
 290         ret = cpu_write_elf64_qemunote(fd_write_vmcore, cpu, s);
 291         if (ret < 0) {
 292             dump_error(s, "dump: failed to write CPU status.\n");
 293             return -1;
 294         }
 295     }
 296
 297     return 0;
 298 }
 299
 300 static int write_elf32_note(DumpState *s)
 301 {
 302     hwaddr begin = s->memory_offset - s->note_size;
 303     Elf32_Phdr phdr;
 304     int endian = s->dump_info.d_endian;
 305     int ret;
 306
 307     memset(&phdr, 0, sizeof(Elf32_Phdr));
 308     phdr.p_type = cpu_convert_to_target32(PT_NOTE, endian);
 309     phdr.p_offset = cpu_convert_to_target32(begin, endian);
 310     phdr.p_paddr = 0;
 311     phdr.p_filesz = cpu_convert_to_target32(s->note_size, endian);
 312     phdr.p_memsz = cpu_convert_to_target32(s->note_size, endian);
 313     phdr.p_vaddr = 0;
 314
 315     ret = fd_write_vmcore(&phdr, sizeof(Elf32_Phdr), s);
 316     if (ret < 0) {
 317         dump_error(s, "dump: failed to write program header table.\n");
 318         return -1;
 319     }
 320
 321     return 0;
 322 }
 323
 324 static int write_elf32_notes(DumpState *s)
 325 {
 326     CPUState *cpu;
 327     int ret;
 328     int id;
 329
 330     CPU_FOREACH(cpu) {
 331         id = cpu_index(cpu);
 332         ret = cpu_write_elf32_note(fd_write_vmcore, cpu, id, s);
 333         if (ret < 0) {
 334             dump_error(s, "dump: failed to write elf notes.\n");
 335             return -1;
 336         }
 337     }
 338
 339     CPU_FOREACH(cpu) {
 340         ret = cpu_write_elf32_qemunote(fd_write_vmcore, cpu, s);
 341         if (ret < 0) {
 342             dump_error(s, "dump: failed to write CPU status.\n");
 343             return -1;
 344         }
 345     }
 346
 347     return 0;
 348 }
 349
 350 static int write_elf_section(DumpState *s, int type)
 351 {
 352     Elf32_Shdr shdr32;
 353     Elf64_Shdr shdr64;
 354     int endian = s->dump_info.d_endian;
 355     int shdr_size;
 356     void *shdr;
 357     int ret;
 358
 359     if (type == 0) {
 360         shdr_size = sizeof(Elf32_Shdr);
 361         memset(&shdr32, 0, shdr_size);
 362         shdr32.sh_info = cpu_convert_to_target32(s->sh_info, endian);
 363         shdr = &shdr32;
 364     } else {
 365         shdr_size = sizeof(Elf64_Shdr);
 366         memset(&shdr64, 0, shdr_size);
 367         shdr64.sh_info = cpu_convert_to_target32(s->sh_info, endian);
 368         shdr = &shdr64;
 369     }
 370
 371     ret = fd_write_vmcore(&shdr, shdr_size, s);
 372     if (ret < 0) {
 373         dump_error(s, "dump: failed to write section header table.\n");
 374         return -1;
 375     }
 376
 377     return 0;
 378 }
 379
 380 static int write_data(DumpState *s, void *buf, int length)
 381 {
 382     int ret;
 383
 384     ret = fd_write_vmcore(buf, length, s);
 385     if (ret < 0) {
 386         dump_error(s, "dump: failed to save memory.\n");
 387         return -1;
 388     }
 389
 390     return 0;
 391 }
 392
 393 /* write the memroy to vmcore. 1 page per I/O. */
 394 static int write_memory(DumpState *s, GuestPhysBlock *block, ram_addr_t start,
 395                         int64_t size)
 396 {
 397     int64_t i;
 398     int ret;
 399
 400     for (i = 0; i < size / TARGET_PAGE_SIZE; i++) {
 401         ret = write_data(s, block->host_addr + start + i * TARGET_PAGE_SIZE,
 402                          TARGET_PAGE_SIZE);
 403         if (ret < 0) {
 404             return ret;
 405         }
 406     }
 407
 408     if ((size % TARGET_PAGE_SIZE) != 0) {
 409         ret = write_data(s, block->host_addr + start + i * TARGET_PAGE_SIZE,
 410                          size % TARGET_PAGE_SIZE);
 411         if (ret < 0) {
 412             return ret;
 413         }
 414     }
 415
 416     return 0;
 417 }
 418
 419 /* get the memory's offset and size in the vmcore */
 420 static void get_offset_range(hwaddr phys_addr,
 421                              ram_addr_t mapping_length,
 422                              DumpState *s,
 423                              hwaddr *p_offset,
 424                              hwaddr *p_filesz)
 425 {
 426     GuestPhysBlock *block;
 427     hwaddr offset = s->memory_offset;
 428     int64_t size_in_block, start;
 429
 430     /* When the memory is not stored into vmcore, offset will be -1 */
 431     *p_offset = -1;
 432     *p_filesz = 0;
 433
 434     if (s->has_filter) {
 435         if (phys_addr < s->begin || phys_addr >= s->begin + s->length) {
 436             return;
 437         }
 438     }
 439
 440     QTAILQ_FOREACH(block, &s->guest_phys_blocks.head, next) {
 441         if (s->has_filter) {
 442             if (block->target_start >= s->begin + s->length ||
 443                 block->target_end <= s->begin) {
 444                 /* This block is out of the range */
 445                 continue;
 446             }
 447
 448             if (s->begin <= block->target_start) {
 449                 start = block->target_start;
 450             } else {
 451                 start = s->begin;
 452             }
 453
 454             size_in_block = block->target_end - start;
 455             if (s->begin + s->length < block->target_end) {
 456                 size_in_block -= block->target_end - (s->begin + s->length);
 457             }
 458         } else {
 459             start = block->target_start;
 460             size_in_block = block->target_end - block->target_start;
 461         }
 462
 463         if (phys_addr >= start && phys_addr < start + size_in_block) {
 464             *p_offset = phys_addr - start + offset;
 465
 466             /* The offset range mapped from the vmcore file must not spill over
 467              * the GuestPhysBlock, clamp it. The rest of the mapping will be
 468              * zero-filled in memory at load time; see
 469              * <http://refspecs.linuxbase.org/elf/gabi4+/ch5.pheader.html>.
 470              */
 471             *p_filesz = phys_addr + mapping_length <= start + size_in_block ?
 472                         mapping_length :
 473                         size_in_block - (phys_addr - start);
 474             return;
 475         }
 476
 477         offset += size_in_block;
 478     }
 479 }
 480
 481 static int write_elf_loads(DumpState *s)
 482 {
 483     hwaddr offset, filesz;
 484     MemoryMapping *memory_mapping;
 485     uint32_t phdr_index = 1;
 486     int ret;
 487     uint32_t max_index;
 488
 489     if (s->have_section) {
 490         max_index = s->sh_info;
 491     } else {
 492         max_index = s->phdr_num;
 493     }
 494
 495     QTAILQ_FOREACH(memory_mapping, &s->list.head, next) {
 496         get_offset_range(memory_mapping->phys_addr,
 497                          memory_mapping->length,
 498                          s, &offset, &filesz);
 499         if (s->dump_info.d_class == ELFCLASS64) {
 500             ret = write_elf64_load(s, memory_mapping, phdr_index++, offset,
 501                                    filesz);
 502         } else {
 503             ret = write_elf32_load(s, memory_mapping, phdr_index++, offset,
 504                                    filesz);
 505         }
 506
 507         if (ret < 0) {
 508             return -1;
 509         }
 510
 511         if (phdr_index >= max_index) {
 512             break;
 513         }
 514     }
 515
 516     return 0;
 517 }
 518
 519 /* write elf header, PT_NOTE and elf note to vmcore. */
 520 static int dump_begin(DumpState *s)
 521 {
 522     int ret;
 523
 524     /*
 525      * the vmcore's format is:
 526      *   --------------
 527      *   |  elf header |
 528      *   --------------
 529      *   |  PT_NOTE    |
 530      *   --------------
 531      *   |  PT_LOAD    |
 532      *   --------------
 533      *   |  ......     |
 534      *   --------------
 535      *   |  PT_LOAD    |
 536      *   --------------
 537      *   |  sec_hdr    |
 538      *   --------------
 539      *   |  elf note   |
 540      *   --------------
 541      *   |  memory     |
 542      *   --------------
 543      *
 544      * we only know where the memory is saved after we write elf note into
 545      * vmcore.
 546      */
 547
 548     /* write elf header to vmcore */
 549     if (s->dump_info.d_class == ELFCLASS64) {
 550         ret = write_elf64_header(s);
 551     } else {
 552         ret = write_elf32_header(s);
 553     }
 554     if (ret < 0) {
 555         return -1;
 556     }
 557
 558     if (s->dump_info.d_class == ELFCLASS64) {
 559         /* write PT_NOTE to vmcore */
 560         if (write_elf64_note(s) < 0) {
 561             return -1;
 562         }
 563
 564         /* write all PT_LOAD to vmcore */
 565         if (write_elf_loads(s) < 0) {
 566             return -1;
 567         }
 568
 569         /* write section to vmcore */
 570         if (s->have_section) {
 571             if (write_elf_section(s, 1) < 0) {
 572                 return -1;
 573             }
 574         }
 575
 576         /* write notes to vmcore */
 577         if (write_elf64_notes(s) < 0) {
 578             return -1;
 579         }
 580
 581     } else {
 582         /* write PT_NOTE to vmcore */
 583         if (write_elf32_note(s) < 0) {
 584             return -1;
 585         }
 586
 587         /* write all PT_LOAD to vmcore */
 588         if (write_elf_loads(s) < 0) {
 589             return -1;
 590         }
 591
 592         /* write section to vmcore */
 593         if (s->have_section) {
 594             if (write_elf_section(s, 0) < 0) {
 595                 return -1;
 596             }
 597         }
 598
 599         /* write notes to vmcore */
 600         if (write_elf32_notes(s) < 0) {
 601             return -1;
 602         }
 603     }
 604
 605     return 0;
 606 }
 607
 608 /* write PT_LOAD to vmcore */
 609 static int dump_completed(DumpState *s)
 610 {
 611     dump_cleanup(s);
 612     return 0;
 613 }
 614
 615 static int get_next_block(DumpState *s, GuestPhysBlock *block)
 616 {
 617     while (1) {
 618         block = QTAILQ_NEXT(block, next);
 619         if (!block) {
 620             /* no more block */
 621             return 1;
 622         }
 623
 624         s->start = 0;
 625         s->next_block = block;
 626         if (s->has_filter) {
 627             if (block->target_start >= s->begin + s->length ||
 628                 block->target_end <= s->begin) {
 629                 /* This block is out of the range */
 630                 continue;
 631             }
 632
 633             if (s->begin > block->target_start) {
 634                 s->start = s->begin - block->target_start;
 635             }
 636         }
 637
 638         return 0;
 639     }
 640 }
 641
 642 /* write all memory to vmcore */
 643 static int dump_iterate(DumpState *s)
 644 {
 645     GuestPhysBlock *block;
 646     int64_t size;
 647     int ret;
 648
 649     while (1) {
 650         block = s->next_block;
 651
 652         size = block->target_end - block->target_start;
 653         if (s->has_filter) {
 654             size -= s->start;
 655             if (s->begin + s->length < block->target_end) {
 656                 size -= block->target_end - (s->begin + s->length);
 657             }
 658         }
 659         ret = write_memory(s, block, s->start, size);
 660         if (ret == -1) {
 661             return ret;
 662         }
 663
 664         ret = get_next_block(s, block);
 665         if (ret == 1) {
 666             dump_completed(s);
 667             return 0;
 668         }
 669     }
 670 }
 671
 672 static int create_vmcore(DumpState *s)
 673 {
 674     int ret;
 675
 676     ret = dump_begin(s);
 677     if (ret < 0) {
 678         return -1;
 679     }
 680
 681     ret = dump_iterate(s);
 682     if (ret < 0) {
 683         return -1;
 684     }
 685
 686     return 0;
 687 }
 688
 689 static ram_addr_t get_start_block(DumpState *s)
 690 {
 691     GuestPhysBlock *block;
 692
 693     if (!s->has_filter) {
 694         s->next_block = QTAILQ_FIRST(&s->guest_phys_blocks.head);
 695         return 0;
 696     }
 697
 698     QTAILQ_FOREACH(block, &s->guest_phys_blocks.head, next) {
 699         if (block->target_start >= s->begin + s->length ||
 700             block->target_end <= s->begin) {
 701             /* This block is out of the range */
 702             continue;
 703         }
 704
 705         s->next_block = block;
 706         if (s->begin > block->target_start) {
 707             s->start = s->begin - block->target_start;
 708         } else {
 709             s->start = 0;
 710         }
 711         return s->start;
 712     }
 713
 714     return -1;
 715 }
 716
 717 static int dump_init(DumpState *s, int fd, bool paging, bool has_filter,
 718                      int64_t begin, int64_t length, Error **errp)
 719 {
 720     CPUState *cpu;
 721     int nr_cpus;
 722     Error *err = NULL;
 723     int ret;
 724
 725     if (runstate_is_running()) {
 726         vm_stop(RUN_STATE_SAVE_VM);
 727         s->resume = true;
 728     } else {
 729         s->resume = false;
 730     }
 731
 732     /* If we use KVM, we should synchronize the registers before we get dump
 733      * info or physmap info.
 734      */
 735     cpu_synchronize_all_states();
 736     nr_cpus = 0;
 737     CPU_FOREACH(cpu) {
 738         nr_cpus++;
 739     }
 740
 741     s->errp = errp;
 742     s->fd = fd;
 743     s->has_filter = has_filter;
 744     s->begin = begin;
 745     s->length = length;
 746
 747     guest_phys_blocks_init(&s->guest_phys_blocks);
 748     guest_phys_blocks_append(&s->guest_phys_blocks);
 749
 750     s->start = get_start_block(s);
 751     if (s->start == -1) {
 752         error_set(errp, QERR_INVALID_PARAMETER, "begin");
 753         goto cleanup;
 754     }
 755
 756     /* get dump info: endian, class and architecture.
 757      * If the target architecture is not supported, cpu_get_dump_info() will
 758      * return -1.
 759      */
 760     ret = cpu_get_dump_info(&s->dump_info, &s->guest_phys_blocks);
 761     if (ret < 0) {
 762         error_set(errp, QERR_UNSUPPORTED);
 763         goto cleanup;
 764     }
 765
 766     s->note_size = cpu_get_note_size(s->dump_info.d_class,
 767                                      s->dump_info.d_machine, nr_cpus);
 768     if (ret < 0) {
 769         error_set(errp, QERR_UNSUPPORTED);
 770         goto cleanup;
 771     }
 772
 773     /* get memory mapping */
 774     memory_mapping_list_init(&s->list);
 775     if (paging) {
 776         qemu_get_guest_memory_mapping(&s->list, &s->guest_phys_blocks, &err);
 777         if (err != NULL) {
 778             error_propagate(errp, err);
 779             goto cleanup;
 780         }
 781     } else {
 782         qemu_get_guest_simple_memory_mapping(&s->list, &s->guest_phys_blocks);
 783     }
 784
 785     if (s->has_filter) {
 786         memory_mapping_filter(&s->list, s->begin, s->length);
 787     }
 788
 789     /*
 790      * calculate phdr_num
 791      *
 792      * the type of ehdr->e_phnum is uint16_t, so we should avoid overflow
 793      */
 794     s->phdr_num = 1; /* PT_NOTE */
 795     if (s->list.num < UINT16_MAX - 2) {
 796         s->phdr_num += s->list.num;
 797         s->have_section = false;
 798     } else {
 799         s->have_section = true;
 800         s->phdr_num = PN_XNUM;
 801         s->sh_info = 1; /* PT_NOTE */
 802
 803         /* the type of shdr->sh_info is uint32_t, so we should avoid overflow */
 804         if (s->list.num <= UINT32_MAX - 1) {
 805             s->sh_info += s->list.num;
 806         } else {
 807             s->sh_info = UINT32_MAX;
 808         }
 809     }
 810
 811     if (s->dump_info.d_class == ELFCLASS64) {
 812         if (s->have_section) {
 813             s->memory_offset = sizeof(Elf64_Ehdr) +
 814                                sizeof(Elf64_Phdr) * s->sh_info +
 815                                sizeof(Elf64_Shdr) + s->note_size;
 816         } else {
 817             s->memory_offset = sizeof(Elf64_Ehdr) +
 818                                sizeof(Elf64_Phdr) * s->phdr_num + s->note_size;
 819         }
 820     } else {
 821         if (s->have_section) {
 822             s->memory_offset = sizeof(Elf32_Ehdr) +
 823                                sizeof(Elf32_Phdr) * s->sh_info +
 824                                sizeof(Elf32_Shdr) + s->note_size;
 825         } else {
 826             s->memory_offset = sizeof(Elf32_Ehdr) +
 827                                sizeof(Elf32_Phdr) * s->phdr_num + s->note_size;
 828         }
 829     }
 830
 831     return 0;
 832
 833 cleanup:
 834     guest_phys_blocks_free(&s->guest_phys_blocks);
 835
 836     if (s->resume) {
 837         vm_start();
 838     }
 839
 840     return -1;
 841 }
 842
 843 void qmp_dump_guest_memory(bool paging, const char *file, bool has_begin,
 844                            int64_t begin, bool has_length, int64_t length,
 845                            Error **errp)
 846 {
 847     const char *p;
 848     int fd = -1;
 849     DumpState *s;
 850     int ret;
 851
 852     if (has_begin && !has_length) {
 853         error_set(errp, QERR_MISSING_PARAMETER, "length");
 854         return;
 855     }
 856     if (!has_begin && has_length) {
 857         error_set(errp, QERR_MISSING_PARAMETER, "begin");
 858         return;
 859     }
 860
 861 #if !defined(WIN32)
 862     if (strstart(file, "fd:", &p)) {
 863         fd = monitor_get_fd(cur_mon, p, errp);
 864         if (fd == -1) {
 865             return;
 866         }
 867     }
 868 #endif
 869
 870     if  (strstart(file, "file:", &p)) {
 871         fd = qemu_open(p, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, S_IRUSR);
 872         if (fd < 0) {
 873             error_setg_file_open(errp, errno, p);
 874             return;
 875         }
 876     }
 877
 878     if (fd == -1) {
 879         error_set(errp, QERR_INVALID_PARAMETER, "protocol");
 880         return;
 881     }
 882
 883     s = g_malloc0(sizeof(DumpState));
 884
 885     ret = dump_init(s, fd, paging, has_begin, begin, length, errp);
 886     if (ret < 0) {
 887         g_free(s);
 888         return;
 889     }
 890
 891     if (create_vmcore(s) < 0 && !error_is_set(s->errp)) {
 892         error_set(errp, QERR_IO_ERROR);
 893     }
 894
 895     g_free(s);
 896 }