1 /* 2 * QEMU System Emulator 3 * 4 * Copyright (c) 2003-2008 Fabrice Bellard 5 * Copyright (c) 2009-2015 Red Hat Inc 6 * 7 * Authors: 8 * Juan Quintela <quintela@redhat.com> 9 * 10 * Permission is hereby granted, free of charge, to any person obtaining a copy 11 * of this software and associated documentation files (the "Software"), to deal 12 * in the Software without restriction, including without limitation the rights 13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 14 * copies of the Software, and to permit persons to whom the Software is 15 * furnished to do so, subject to the following conditions: 16 * 17 * The above copyright notice and this permission notice shall be included in 18 * all copies or substantial portions of the Software. 19 * 20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 26 * THE SOFTWARE. 27 */ 28 29 #include "qemu/osdep.h" 30 #include "hw/boards.h" 31 #include "net/net.h" 32 #include "migration.h" 33 #include "migration/snapshot.h" 34 #include "migration/vmstate.h" 35 #include "migration/misc.h" 36 #include "migration/register.h" 37 #include "migration/global_state.h" 38 #include "ram.h" 39 #include "qemu-file-channel.h" 40 #include "qemu-file.h" 41 #include "savevm.h" 42 #include "postcopy-ram.h" 43 #include "qapi/error.h" 44 #include "qapi/qapi-commands-migration.h" 45 #include "qapi/qmp/qerror.h" 46 #include "qemu/error-report.h" 47 #include "sysemu/cpus.h" 48 #include "exec/memory.h" 49 #include "exec/target_page.h" 50 #include "trace.h" 51 #include "qemu/iov.h" 52 #include "qemu/main-loop.h" 53 #include "block/snapshot.h" 54 #include "qemu/cutils.h" 55 #include "io/channel-buffer.h" 56 #include "io/channel-file.h" 57 #include "sysemu/replay.h" 58 #include "sysemu/runstate.h" 59 #include "sysemu/sysemu.h" 60 #include "sysemu/xen.h" 61 #include "qjson.h" 62 #include "migration/colo.h" 63 #include "qemu/bitmap.h" 64 #include "net/announce.h" 65 66 const unsigned int postcopy_ram_discard_version = 0; 67 68 /* Subcommands for QEMU_VM_COMMAND */ 69 enum qemu_vm_cmd { 70 MIG_CMD_INVALID = 0, /* Must be 0 */ 71 MIG_CMD_OPEN_RETURN_PATH, /* Tell the dest to open the Return path */ 72 MIG_CMD_PING, /* Request a PONG on the RP */ 73 74 MIG_CMD_POSTCOPY_ADVISE, /* Prior to any page transfers, just 75 warn we might want to do PC */ 76 MIG_CMD_POSTCOPY_LISTEN, /* Start listening for incoming 77 pages as it's running. */ 78 MIG_CMD_POSTCOPY_RUN, /* Start execution */ 79 80 MIG_CMD_POSTCOPY_RAM_DISCARD, /* A list of pages to discard that 81 were previously sent during 82 precopy but are dirty. */ 83 MIG_CMD_PACKAGED, /* Send a wrapped stream within this stream */ 84 MIG_CMD_ENABLE_COLO, /* Enable COLO */ 85 MIG_CMD_POSTCOPY_RESUME, /* resume postcopy on dest */ 86 MIG_CMD_RECV_BITMAP, /* Request for recved bitmap on dst */ 87 MIG_CMD_MAX 88 }; 89 90 #define MAX_VM_CMD_PACKAGED_SIZE UINT32_MAX 91 static struct mig_cmd_args { 92 ssize_t len; /* -1 = variable */ 93 const char *name; 94 } mig_cmd_args[] = { 95 [MIG_CMD_INVALID] = { .len = -1, .name = "INVALID" }, 96 [MIG_CMD_OPEN_RETURN_PATH] = { .len = 0, .name = "OPEN_RETURN_PATH" }, 97 [MIG_CMD_PING] = { .len = sizeof(uint32_t), .name = "PING" }, 98 [MIG_CMD_POSTCOPY_ADVISE] = { .len = -1, .name = "POSTCOPY_ADVISE" }, 99 [MIG_CMD_POSTCOPY_LISTEN] = { .len = 0, .name = "POSTCOPY_LISTEN" }, 100 [MIG_CMD_POSTCOPY_RUN] = { .len = 0, .name = "POSTCOPY_RUN" }, 101 [MIG_CMD_POSTCOPY_RAM_DISCARD] = { 102 .len = -1, .name = "POSTCOPY_RAM_DISCARD" }, 103 [MIG_CMD_POSTCOPY_RESUME] = { .len = 0, .name = "POSTCOPY_RESUME" }, 104 [MIG_CMD_PACKAGED] = { .len = 4, .name = "PACKAGED" }, 105 [MIG_CMD_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" }, 106 [MIG_CMD_MAX] = { .len = -1, .name = "MAX" }, 107 }; 108 109 /* Note for MIG_CMD_POSTCOPY_ADVISE: 110 * The format of arguments is depending on postcopy mode: 111 * - postcopy RAM only 112 * uint64_t host page size 113 * uint64_t taget page size 114 * 115 * - postcopy RAM and postcopy dirty bitmaps 116 * format is the same as for postcopy RAM only 117 * 118 * - postcopy dirty bitmaps only 119 * Nothing. Command length field is 0. 120 * 121 * Be careful: adding a new postcopy entity with some other parameters should 122 * not break format self-description ability. Good way is to introduce some 123 * generic extendable format with an exception for two old entities. 124 */ 125 126 /***********************************************************/ 127 /* savevm/loadvm support */ 128 129 static ssize_t block_writev_buffer(void *opaque, struct iovec *iov, int iovcnt, 130 int64_t pos, Error **errp) 131 { 132 int ret; 133 QEMUIOVector qiov; 134 135 qemu_iovec_init_external(&qiov, iov, iovcnt); 136 ret = bdrv_writev_vmstate(opaque, &qiov, pos); 137 if (ret < 0) { 138 return ret; 139 } 140 141 return qiov.size; 142 } 143 144 static ssize_t block_get_buffer(void *opaque, uint8_t *buf, int64_t pos, 145 size_t size, Error **errp) 146 { 147 return bdrv_load_vmstate(opaque, buf, pos, size); 148 } 149 150 static int bdrv_fclose(void *opaque, Error **errp) 151 { 152 return bdrv_flush(opaque); 153 } 154 155 static const QEMUFileOps bdrv_read_ops = { 156 .get_buffer = block_get_buffer, 157 .close = bdrv_fclose 158 }; 159 160 static const QEMUFileOps bdrv_write_ops = { 161 .writev_buffer = block_writev_buffer, 162 .close = bdrv_fclose 163 }; 164 165 static QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int is_writable) 166 { 167 if (is_writable) { 168 return qemu_fopen_ops(bs, &bdrv_write_ops); 169 } 170 return qemu_fopen_ops(bs, &bdrv_read_ops); 171 } 172 173 174 /* QEMUFile timer support. 175 * Not in qemu-file.c to not add qemu-timer.c as dependency to qemu-file.c 176 */ 177 178 void timer_put(QEMUFile *f, QEMUTimer *ts) 179 { 180 uint64_t expire_time; 181 182 expire_time = timer_expire_time_ns(ts); 183 qemu_put_be64(f, expire_time); 184 } 185 186 void timer_get(QEMUFile *f, QEMUTimer *ts) 187 { 188 uint64_t expire_time; 189 190 expire_time = qemu_get_be64(f); 191 if (expire_time != -1) { 192 timer_mod_ns(ts, expire_time); 193 } else { 194 timer_del(ts); 195 } 196 } 197 198 199 /* VMState timer support. 200 * Not in vmstate.c to not add qemu-timer.c as dependency to vmstate.c 201 */ 202 203 static int get_timer(QEMUFile *f, void *pv, size_t size, 204 const VMStateField *field) 205 { 206 QEMUTimer *v = pv; 207 timer_get(f, v); 208 return 0; 209 } 210 211 static int put_timer(QEMUFile *f, void *pv, size_t size, 212 const VMStateField *field, QJSON *vmdesc) 213 { 214 QEMUTimer *v = pv; 215 timer_put(f, v); 216 217 return 0; 218 } 219 220 const VMStateInfo vmstate_info_timer = { 221 .name = "timer", 222 .get = get_timer, 223 .put = put_timer, 224 }; 225 226 227 typedef struct CompatEntry { 228 char idstr[256]; 229 int instance_id; 230 } CompatEntry; 231 232 typedef struct SaveStateEntry { 233 QTAILQ_ENTRY(SaveStateEntry) entry; 234 char idstr[256]; 235 uint32_t instance_id; 236 int alias_id; 237 int version_id; 238 /* version id read from the stream */ 239 int load_version_id; 240 int section_id; 241 /* section id read from the stream */ 242 int load_section_id; 243 const SaveVMHandlers *ops; 244 const VMStateDescription *vmsd; 245 void *opaque; 246 CompatEntry *compat; 247 int is_ram; 248 } SaveStateEntry; 249 250 typedef struct SaveState { 251 QTAILQ_HEAD(, SaveStateEntry) handlers; 252 SaveStateEntry *handler_pri_head[MIG_PRI_MAX + 1]; 253 int global_section_id; 254 uint32_t len; 255 const char *name; 256 uint32_t target_page_bits; 257 uint32_t caps_count; 258 MigrationCapability *capabilities; 259 QemuUUID uuid; 260 } SaveState; 261 262 static SaveState savevm_state = { 263 .handlers = QTAILQ_HEAD_INITIALIZER(savevm_state.handlers), 264 .handler_pri_head = { [MIG_PRI_DEFAULT ... MIG_PRI_MAX] = NULL }, 265 .global_section_id = 0, 266 }; 267 268 static bool should_validate_capability(int capability) 269 { 270 assert(capability >= 0 && capability < MIGRATION_CAPABILITY__MAX); 271 /* Validate only new capabilities to keep compatibility. */ 272 switch (capability) { 273 case MIGRATION_CAPABILITY_X_IGNORE_SHARED: 274 return true; 275 default: 276 return false; 277 } 278 } 279 280 static uint32_t get_validatable_capabilities_count(void) 281 { 282 MigrationState *s = migrate_get_current(); 283 uint32_t result = 0; 284 int i; 285 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { 286 if (should_validate_capability(i) && s->enabled_capabilities[i]) { 287 result++; 288 } 289 } 290 return result; 291 } 292 293 static int configuration_pre_save(void *opaque) 294 { 295 SaveState *state = opaque; 296 const char *current_name = MACHINE_GET_CLASS(current_machine)->name; 297 MigrationState *s = migrate_get_current(); 298 int i, j; 299 300 state->len = strlen(current_name); 301 state->name = current_name; 302 state->target_page_bits = qemu_target_page_bits(); 303 304 state->caps_count = get_validatable_capabilities_count(); 305 state->capabilities = g_renew(MigrationCapability, state->capabilities, 306 state->caps_count); 307 for (i = j = 0; i < MIGRATION_CAPABILITY__MAX; i++) { 308 if (should_validate_capability(i) && s->enabled_capabilities[i]) { 309 state->capabilities[j++] = i; 310 } 311 } 312 state->uuid = qemu_uuid; 313 314 return 0; 315 } 316 317 static int configuration_pre_load(void *opaque) 318 { 319 SaveState *state = opaque; 320 321 /* If there is no target-page-bits subsection it means the source 322 * predates the variable-target-page-bits support and is using the 323 * minimum possible value for this CPU. 324 */ 325 state->target_page_bits = qemu_target_page_bits_min(); 326 return 0; 327 } 328 329 static bool configuration_validate_capabilities(SaveState *state) 330 { 331 bool ret = true; 332 MigrationState *s = migrate_get_current(); 333 unsigned long *source_caps_bm; 334 int i; 335 336 source_caps_bm = bitmap_new(MIGRATION_CAPABILITY__MAX); 337 for (i = 0; i < state->caps_count; i++) { 338 MigrationCapability capability = state->capabilities[i]; 339 set_bit(capability, source_caps_bm); 340 } 341 342 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { 343 bool source_state, target_state; 344 if (!should_validate_capability(i)) { 345 continue; 346 } 347 source_state = test_bit(i, source_caps_bm); 348 target_state = s->enabled_capabilities[i]; 349 if (source_state != target_state) { 350 error_report("Capability %s is %s, but received capability is %s", 351 MigrationCapability_str(i), 352 target_state ? "on" : "off", 353 source_state ? "on" : "off"); 354 ret = false; 355 /* Don't break here to report all failed capabilities */ 356 } 357 } 358 359 g_free(source_caps_bm); 360 return ret; 361 } 362 363 static int configuration_post_load(void *opaque, int version_id) 364 { 365 SaveState *state = opaque; 366 const char *current_name = MACHINE_GET_CLASS(current_machine)->name; 367 368 if (strncmp(state->name, current_name, state->len) != 0) { 369 error_report("Machine type received is '%.*s' and local is '%s'", 370 (int) state->len, state->name, current_name); 371 return -EINVAL; 372 } 373 374 if (state->target_page_bits != qemu_target_page_bits()) { 375 error_report("Received TARGET_PAGE_BITS is %d but local is %d", 376 state->target_page_bits, qemu_target_page_bits()); 377 return -EINVAL; 378 } 379 380 if (!configuration_validate_capabilities(state)) { 381 return -EINVAL; 382 } 383 384 return 0; 385 } 386 387 static int get_capability(QEMUFile *f, void *pv, size_t size, 388 const VMStateField *field) 389 { 390 MigrationCapability *capability = pv; 391 char capability_str[UINT8_MAX + 1]; 392 uint8_t len; 393 int i; 394 395 len = qemu_get_byte(f); 396 qemu_get_buffer(f, (uint8_t *)capability_str, len); 397 capability_str[len] = '\0'; 398 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { 399 if (!strcmp(MigrationCapability_str(i), capability_str)) { 400 *capability = i; 401 return 0; 402 } 403 } 404 error_report("Received unknown capability %s", capability_str); 405 return -EINVAL; 406 } 407 408 static int put_capability(QEMUFile *f, void *pv, size_t size, 409 const VMStateField *field, QJSON *vmdesc) 410 { 411 MigrationCapability *capability = pv; 412 const char *capability_str = MigrationCapability_str(*capability); 413 size_t len = strlen(capability_str); 414 assert(len <= UINT8_MAX); 415 416 qemu_put_byte(f, len); 417 qemu_put_buffer(f, (uint8_t *)capability_str, len); 418 return 0; 419 } 420 421 static const VMStateInfo vmstate_info_capability = { 422 .name = "capability", 423 .get = get_capability, 424 .put = put_capability, 425 }; 426 427 /* The target-page-bits subsection is present only if the 428 * target page size is not the same as the default (ie the 429 * minimum page size for a variable-page-size guest CPU). 430 * If it is present then it contains the actual target page 431 * bits for the machine, and migration will fail if the 432 * two ends don't agree about it. 433 */ 434 static bool vmstate_target_page_bits_needed(void *opaque) 435 { 436 return qemu_target_page_bits() 437 > qemu_target_page_bits_min(); 438 } 439 440 static const VMStateDescription vmstate_target_page_bits = { 441 .name = "configuration/target-page-bits", 442 .version_id = 1, 443 .minimum_version_id = 1, 444 .needed = vmstate_target_page_bits_needed, 445 .fields = (VMStateField[]) { 446 VMSTATE_UINT32(target_page_bits, SaveState), 447 VMSTATE_END_OF_LIST() 448 } 449 }; 450 451 static bool vmstate_capabilites_needed(void *opaque) 452 { 453 return get_validatable_capabilities_count() > 0; 454 } 455 456 static const VMStateDescription vmstate_capabilites = { 457 .name = "configuration/capabilities", 458 .version_id = 1, 459 .minimum_version_id = 1, 460 .needed = vmstate_capabilites_needed, 461 .fields = (VMStateField[]) { 462 VMSTATE_UINT32_V(caps_count, SaveState, 1), 463 VMSTATE_VARRAY_UINT32_ALLOC(capabilities, SaveState, caps_count, 1, 464 vmstate_info_capability, 465 MigrationCapability), 466 VMSTATE_END_OF_LIST() 467 } 468 }; 469 470 static bool vmstate_uuid_needed(void *opaque) 471 { 472 return qemu_uuid_set && migrate_validate_uuid(); 473 } 474 475 static int vmstate_uuid_post_load(void *opaque, int version_id) 476 { 477 SaveState *state = opaque; 478 char uuid_src[UUID_FMT_LEN + 1]; 479 char uuid_dst[UUID_FMT_LEN + 1]; 480 481 if (!qemu_uuid_set) { 482 /* 483 * It's warning because user might not know UUID in some cases, 484 * e.g. load an old snapshot 485 */ 486 qemu_uuid_unparse(&state->uuid, uuid_src); 487 warn_report("UUID is received %s, but local uuid isn't set", 488 uuid_src); 489 return 0; 490 } 491 if (!qemu_uuid_is_equal(&state->uuid, &qemu_uuid)) { 492 qemu_uuid_unparse(&state->uuid, uuid_src); 493 qemu_uuid_unparse(&qemu_uuid, uuid_dst); 494 error_report("UUID received is %s and local is %s", uuid_src, uuid_dst); 495 return -EINVAL; 496 } 497 return 0; 498 } 499 500 static const VMStateDescription vmstate_uuid = { 501 .name = "configuration/uuid", 502 .version_id = 1, 503 .minimum_version_id = 1, 504 .needed = vmstate_uuid_needed, 505 .post_load = vmstate_uuid_post_load, 506 .fields = (VMStateField[]) { 507 VMSTATE_UINT8_ARRAY_V(uuid.data, SaveState, sizeof(QemuUUID), 1), 508 VMSTATE_END_OF_LIST() 509 } 510 }; 511 512 static const VMStateDescription vmstate_configuration = { 513 .name = "configuration", 514 .version_id = 1, 515 .pre_load = configuration_pre_load, 516 .post_load = configuration_post_load, 517 .pre_save = configuration_pre_save, 518 .fields = (VMStateField[]) { 519 VMSTATE_UINT32(len, SaveState), 520 VMSTATE_VBUFFER_ALLOC_UINT32(name, SaveState, 0, NULL, len), 521 VMSTATE_END_OF_LIST() 522 }, 523 .subsections = (const VMStateDescription*[]) { 524 &vmstate_target_page_bits, 525 &vmstate_capabilites, 526 &vmstate_uuid, 527 NULL 528 } 529 }; 530 531 static void dump_vmstate_vmsd(FILE *out_file, 532 const VMStateDescription *vmsd, int indent, 533 bool is_subsection); 534 535 static void dump_vmstate_vmsf(FILE *out_file, const VMStateField *field, 536 int indent) 537 { 538 fprintf(out_file, "%*s{\n", indent, ""); 539 indent += 2; 540 fprintf(out_file, "%*s\"field\": \"%s\",\n", indent, "", field->name); 541 fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "", 542 field->version_id); 543 fprintf(out_file, "%*s\"field_exists\": %s,\n", indent, "", 544 field->field_exists ? "true" : "false"); 545 fprintf(out_file, "%*s\"size\": %zu", indent, "", field->size); 546 if (field->vmsd != NULL) { 547 fprintf(out_file, ",\n"); 548 dump_vmstate_vmsd(out_file, field->vmsd, indent, false); 549 } 550 fprintf(out_file, "\n%*s}", indent - 2, ""); 551 } 552 553 static void dump_vmstate_vmss(FILE *out_file, 554 const VMStateDescription **subsection, 555 int indent) 556 { 557 if (*subsection != NULL) { 558 dump_vmstate_vmsd(out_file, *subsection, indent, true); 559 } 560 } 561 562 static void dump_vmstate_vmsd(FILE *out_file, 563 const VMStateDescription *vmsd, int indent, 564 bool is_subsection) 565 { 566 if (is_subsection) { 567 fprintf(out_file, "%*s{\n", indent, ""); 568 } else { 569 fprintf(out_file, "%*s\"%s\": {\n", indent, "", "Description"); 570 } 571 indent += 2; 572 fprintf(out_file, "%*s\"name\": \"%s\",\n", indent, "", vmsd->name); 573 fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "", 574 vmsd->version_id); 575 fprintf(out_file, "%*s\"minimum_version_id\": %d", indent, "", 576 vmsd->minimum_version_id); 577 if (vmsd->fields != NULL) { 578 const VMStateField *field = vmsd->fields; 579 bool first; 580 581 fprintf(out_file, ",\n%*s\"Fields\": [\n", indent, ""); 582 first = true; 583 while (field->name != NULL) { 584 if (field->flags & VMS_MUST_EXIST) { 585 /* Ignore VMSTATE_VALIDATE bits; these don't get migrated */ 586 field++; 587 continue; 588 } 589 if (!first) { 590 fprintf(out_file, ",\n"); 591 } 592 dump_vmstate_vmsf(out_file, field, indent + 2); 593 field++; 594 first = false; 595 } 596 fprintf(out_file, "\n%*s]", indent, ""); 597 } 598 if (vmsd->subsections != NULL) { 599 const VMStateDescription **subsection = vmsd->subsections; 600 bool first; 601 602 fprintf(out_file, ",\n%*s\"Subsections\": [\n", indent, ""); 603 first = true; 604 while (*subsection != NULL) { 605 if (!first) { 606 fprintf(out_file, ",\n"); 607 } 608 dump_vmstate_vmss(out_file, subsection, indent + 2); 609 subsection++; 610 first = false; 611 } 612 fprintf(out_file, "\n%*s]", indent, ""); 613 } 614 fprintf(out_file, "\n%*s}", indent - 2, ""); 615 } 616 617 static void dump_machine_type(FILE *out_file) 618 { 619 MachineClass *mc; 620 621 mc = MACHINE_GET_CLASS(current_machine); 622 623 fprintf(out_file, " \"vmschkmachine\": {\n"); 624 fprintf(out_file, " \"Name\": \"%s\"\n", mc->name); 625 fprintf(out_file, " },\n"); 626 } 627 628 void dump_vmstate_json_to_file(FILE *out_file) 629 { 630 GSList *list, *elt; 631 bool first; 632 633 fprintf(out_file, "{\n"); 634 dump_machine_type(out_file); 635 636 first = true; 637 list = object_class_get_list(TYPE_DEVICE, true); 638 for (elt = list; elt; elt = elt->next) { 639 DeviceClass *dc = OBJECT_CLASS_CHECK(DeviceClass, elt->data, 640 TYPE_DEVICE); 641 const char *name; 642 int indent = 2; 643 644 if (!dc->vmsd) { 645 continue; 646 } 647 648 if (!first) { 649 fprintf(out_file, ",\n"); 650 } 651 name = object_class_get_name(OBJECT_CLASS(dc)); 652 fprintf(out_file, "%*s\"%s\": {\n", indent, "", name); 653 indent += 2; 654 fprintf(out_file, "%*s\"Name\": \"%s\",\n", indent, "", name); 655 fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "", 656 dc->vmsd->version_id); 657 fprintf(out_file, "%*s\"minimum_version_id\": %d,\n", indent, "", 658 dc->vmsd->minimum_version_id); 659 660 dump_vmstate_vmsd(out_file, dc->vmsd, indent, false); 661 662 fprintf(out_file, "\n%*s}", indent - 2, ""); 663 first = false; 664 } 665 fprintf(out_file, "\n}\n"); 666 fclose(out_file); 667 g_slist_free(list); 668 } 669 670 static uint32_t calculate_new_instance_id(const char *idstr) 671 { 672 SaveStateEntry *se; 673 uint32_t instance_id = 0; 674 675 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 676 if (strcmp(idstr, se->idstr) == 0 677 && instance_id <= se->instance_id) { 678 instance_id = se->instance_id + 1; 679 } 680 } 681 /* Make sure we never loop over without being noticed */ 682 assert(instance_id != VMSTATE_INSTANCE_ID_ANY); 683 return instance_id; 684 } 685 686 static int calculate_compat_instance_id(const char *idstr) 687 { 688 SaveStateEntry *se; 689 int instance_id = 0; 690 691 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 692 if (!se->compat) { 693 continue; 694 } 695 696 if (strcmp(idstr, se->compat->idstr) == 0 697 && instance_id <= se->compat->instance_id) { 698 instance_id = se->compat->instance_id + 1; 699 } 700 } 701 return instance_id; 702 } 703 704 static inline MigrationPriority save_state_priority(SaveStateEntry *se) 705 { 706 if (se->vmsd) { 707 return se->vmsd->priority; 708 } 709 return MIG_PRI_DEFAULT; 710 } 711 712 static void savevm_state_handler_insert(SaveStateEntry *nse) 713 { 714 MigrationPriority priority = save_state_priority(nse); 715 SaveStateEntry *se; 716 int i; 717 718 assert(priority <= MIG_PRI_MAX); 719 720 for (i = priority - 1; i >= 0; i--) { 721 se = savevm_state.handler_pri_head[i]; 722 if (se != NULL) { 723 assert(save_state_priority(se) < priority); 724 break; 725 } 726 } 727 728 if (i >= 0) { 729 QTAILQ_INSERT_BEFORE(se, nse, entry); 730 } else { 731 QTAILQ_INSERT_TAIL(&savevm_state.handlers, nse, entry); 732 } 733 734 if (savevm_state.handler_pri_head[priority] == NULL) { 735 savevm_state.handler_pri_head[priority] = nse; 736 } 737 } 738 739 static void savevm_state_handler_remove(SaveStateEntry *se) 740 { 741 SaveStateEntry *next; 742 MigrationPriority priority = save_state_priority(se); 743 744 if (se == savevm_state.handler_pri_head[priority]) { 745 next = QTAILQ_NEXT(se, entry); 746 if (next != NULL && save_state_priority(next) == priority) { 747 savevm_state.handler_pri_head[priority] = next; 748 } else { 749 savevm_state.handler_pri_head[priority] = NULL; 750 } 751 } 752 QTAILQ_REMOVE(&savevm_state.handlers, se, entry); 753 } 754 755 /* TODO: Individual devices generally have very little idea about the rest 756 of the system, so instance_id should be removed/replaced. 757 Meanwhile pass -1 as instance_id if you do not already have a clearly 758 distinguishing id for all instances of your device class. */ 759 int register_savevm_live(const char *idstr, 760 uint32_t instance_id, 761 int version_id, 762 const SaveVMHandlers *ops, 763 void *opaque) 764 { 765 SaveStateEntry *se; 766 767 se = g_new0(SaveStateEntry, 1); 768 se->version_id = version_id; 769 se->section_id = savevm_state.global_section_id++; 770 se->ops = ops; 771 se->opaque = opaque; 772 se->vmsd = NULL; 773 /* if this is a live_savem then set is_ram */ 774 if (ops->save_setup != NULL) { 775 se->is_ram = 1; 776 } 777 778 pstrcat(se->idstr, sizeof(se->idstr), idstr); 779 780 if (instance_id == VMSTATE_INSTANCE_ID_ANY) { 781 se->instance_id = calculate_new_instance_id(se->idstr); 782 } else { 783 se->instance_id = instance_id; 784 } 785 assert(!se->compat || se->instance_id == 0); 786 savevm_state_handler_insert(se); 787 return 0; 788 } 789 790 void unregister_savevm(VMStateIf *obj, const char *idstr, void *opaque) 791 { 792 SaveStateEntry *se, *new_se; 793 char id[256] = ""; 794 795 if (obj) { 796 char *oid = vmstate_if_get_id(obj); 797 if (oid) { 798 pstrcpy(id, sizeof(id), oid); 799 pstrcat(id, sizeof(id), "/"); 800 g_free(oid); 801 } 802 } 803 pstrcat(id, sizeof(id), idstr); 804 805 QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) { 806 if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) { 807 savevm_state_handler_remove(se); 808 g_free(se->compat); 809 g_free(se); 810 } 811 } 812 } 813 814 int vmstate_register_with_alias_id(VMStateIf *obj, uint32_t instance_id, 815 const VMStateDescription *vmsd, 816 void *opaque, int alias_id, 817 int required_for_version, 818 Error **errp) 819 { 820 SaveStateEntry *se; 821 822 /* If this triggers, alias support can be dropped for the vmsd. */ 823 assert(alias_id == -1 || required_for_version >= vmsd->minimum_version_id); 824 825 se = g_new0(SaveStateEntry, 1); 826 se->version_id = vmsd->version_id; 827 se->section_id = savevm_state.global_section_id++; 828 se->opaque = opaque; 829 se->vmsd = vmsd; 830 se->alias_id = alias_id; 831 832 if (obj) { 833 char *id = vmstate_if_get_id(obj); 834 if (id) { 835 if (snprintf(se->idstr, sizeof(se->idstr), "%s/", id) >= 836 sizeof(se->idstr)) { 837 error_setg(errp, "Path too long for VMState (%s)", id); 838 g_free(id); 839 g_free(se); 840 841 return -1; 842 } 843 g_free(id); 844 845 se->compat = g_new0(CompatEntry, 1); 846 pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), vmsd->name); 847 se->compat->instance_id = instance_id == VMSTATE_INSTANCE_ID_ANY ? 848 calculate_compat_instance_id(vmsd->name) : instance_id; 849 instance_id = VMSTATE_INSTANCE_ID_ANY; 850 } 851 } 852 pstrcat(se->idstr, sizeof(se->idstr), vmsd->name); 853 854 if (instance_id == VMSTATE_INSTANCE_ID_ANY) { 855 se->instance_id = calculate_new_instance_id(se->idstr); 856 } else { 857 se->instance_id = instance_id; 858 } 859 assert(!se->compat || se->instance_id == 0); 860 savevm_state_handler_insert(se); 861 return 0; 862 } 863 864 void vmstate_unregister(VMStateIf *obj, const VMStateDescription *vmsd, 865 void *opaque) 866 { 867 SaveStateEntry *se, *new_se; 868 869 QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) { 870 if (se->vmsd == vmsd && se->opaque == opaque) { 871 savevm_state_handler_remove(se); 872 g_free(se->compat); 873 g_free(se); 874 } 875 } 876 } 877 878 static int vmstate_load(QEMUFile *f, SaveStateEntry *se) 879 { 880 trace_vmstate_load(se->idstr, se->vmsd ? se->vmsd->name : "(old)"); 881 if (!se->vmsd) { /* Old style */ 882 return se->ops->load_state(f, se->opaque, se->load_version_id); 883 } 884 return vmstate_load_state(f, se->vmsd, se->opaque, se->load_version_id); 885 } 886 887 static void vmstate_save_old_style(QEMUFile *f, SaveStateEntry *se, QJSON *vmdesc) 888 { 889 int64_t old_offset, size; 890 891 old_offset = qemu_ftell_fast(f); 892 se->ops->save_state(f, se->opaque); 893 size = qemu_ftell_fast(f) - old_offset; 894 895 if (vmdesc) { 896 json_prop_int(vmdesc, "size", size); 897 json_start_array(vmdesc, "fields"); 898 json_start_object(vmdesc, NULL); 899 json_prop_str(vmdesc, "name", "data"); 900 json_prop_int(vmdesc, "size", size); 901 json_prop_str(vmdesc, "type", "buffer"); 902 json_end_object(vmdesc); 903 json_end_array(vmdesc); 904 } 905 } 906 907 static int vmstate_save(QEMUFile *f, SaveStateEntry *se, QJSON *vmdesc) 908 { 909 trace_vmstate_save(se->idstr, se->vmsd ? se->vmsd->name : "(old)"); 910 if (!se->vmsd) { 911 vmstate_save_old_style(f, se, vmdesc); 912 return 0; 913 } 914 return vmstate_save_state(f, se->vmsd, se->opaque, vmdesc); 915 } 916 917 /* 918 * Write the header for device section (QEMU_VM_SECTION START/END/PART/FULL) 919 */ 920 static void save_section_header(QEMUFile *f, SaveStateEntry *se, 921 uint8_t section_type) 922 { 923 qemu_put_byte(f, section_type); 924 qemu_put_be32(f, se->section_id); 925 926 if (section_type == QEMU_VM_SECTION_FULL || 927 section_type == QEMU_VM_SECTION_START) { 928 /* ID string */ 929 size_t len = strlen(se->idstr); 930 qemu_put_byte(f, len); 931 qemu_put_buffer(f, (uint8_t *)se->idstr, len); 932 933 qemu_put_be32(f, se->instance_id); 934 qemu_put_be32(f, se->version_id); 935 } 936 } 937 938 /* 939 * Write a footer onto device sections that catches cases misformatted device 940 * sections. 941 */ 942 static void save_section_footer(QEMUFile *f, SaveStateEntry *se) 943 { 944 if (migrate_get_current()->send_section_footer) { 945 qemu_put_byte(f, QEMU_VM_SECTION_FOOTER); 946 qemu_put_be32(f, se->section_id); 947 } 948 } 949 950 /** 951 * qemu_savevm_command_send: Send a 'QEMU_VM_COMMAND' type element with the 952 * command and associated data. 953 * 954 * @f: File to send command on 955 * @command: Command type to send 956 * @len: Length of associated data 957 * @data: Data associated with command. 958 */ 959 static void qemu_savevm_command_send(QEMUFile *f, 960 enum qemu_vm_cmd command, 961 uint16_t len, 962 uint8_t *data) 963 { 964 trace_savevm_command_send(command, len); 965 qemu_put_byte(f, QEMU_VM_COMMAND); 966 qemu_put_be16(f, (uint16_t)command); 967 qemu_put_be16(f, len); 968 qemu_put_buffer(f, data, len); 969 qemu_fflush(f); 970 } 971 972 void qemu_savevm_send_colo_enable(QEMUFile *f) 973 { 974 trace_savevm_send_colo_enable(); 975 qemu_savevm_command_send(f, MIG_CMD_ENABLE_COLO, 0, NULL); 976 } 977 978 void qemu_savevm_send_ping(QEMUFile *f, uint32_t value) 979 { 980 uint32_t buf; 981 982 trace_savevm_send_ping(value); 983 buf = cpu_to_be32(value); 984 qemu_savevm_command_send(f, MIG_CMD_PING, sizeof(value), (uint8_t *)&buf); 985 } 986 987 void qemu_savevm_send_open_return_path(QEMUFile *f) 988 { 989 trace_savevm_send_open_return_path(); 990 qemu_savevm_command_send(f, MIG_CMD_OPEN_RETURN_PATH, 0, NULL); 991 } 992 993 /* We have a buffer of data to send; we don't want that all to be loaded 994 * by the command itself, so the command contains just the length of the 995 * extra buffer that we then send straight after it. 996 * TODO: Must be a better way to organise that 997 * 998 * Returns: 999 * 0 on success 1000 * -ve on error 1001 */ 1002 int qemu_savevm_send_packaged(QEMUFile *f, const uint8_t *buf, size_t len) 1003 { 1004 uint32_t tmp; 1005 1006 if (len > MAX_VM_CMD_PACKAGED_SIZE) { 1007 error_report("%s: Unreasonably large packaged state: %zu", 1008 __func__, len); 1009 return -1; 1010 } 1011 1012 tmp = cpu_to_be32(len); 1013 1014 trace_qemu_savevm_send_packaged(); 1015 qemu_savevm_command_send(f, MIG_CMD_PACKAGED, 4, (uint8_t *)&tmp); 1016 1017 qemu_put_buffer(f, buf, len); 1018 1019 return 0; 1020 } 1021 1022 /* Send prior to any postcopy transfer */ 1023 void qemu_savevm_send_postcopy_advise(QEMUFile *f) 1024 { 1025 if (migrate_postcopy_ram()) { 1026 uint64_t tmp[2]; 1027 tmp[0] = cpu_to_be64(ram_pagesize_summary()); 1028 tmp[1] = cpu_to_be64(qemu_target_page_size()); 1029 1030 trace_qemu_savevm_send_postcopy_advise(); 1031 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_ADVISE, 1032 16, (uint8_t *)tmp); 1033 } else { 1034 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_ADVISE, 0, NULL); 1035 } 1036 } 1037 1038 /* Sent prior to starting the destination running in postcopy, discard pages 1039 * that have already been sent but redirtied on the source. 1040 * CMD_POSTCOPY_RAM_DISCARD consist of: 1041 * byte version (0) 1042 * byte Length of name field (not including 0) 1043 * n x byte RAM block name 1044 * byte 0 terminator (just for safety) 1045 * n x Byte ranges within the named RAMBlock 1046 * be64 Start of the range 1047 * be64 Length 1048 * 1049 * name: RAMBlock name that these entries are part of 1050 * len: Number of page entries 1051 * start_list: 'len' addresses 1052 * length_list: 'len' addresses 1053 * 1054 */ 1055 void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name, 1056 uint16_t len, 1057 uint64_t *start_list, 1058 uint64_t *length_list) 1059 { 1060 uint8_t *buf; 1061 uint16_t tmplen; 1062 uint16_t t; 1063 size_t name_len = strlen(name); 1064 1065 trace_qemu_savevm_send_postcopy_ram_discard(name, len); 1066 assert(name_len < 256); 1067 buf = g_malloc0(1 + 1 + name_len + 1 + (8 + 8) * len); 1068 buf[0] = postcopy_ram_discard_version; 1069 buf[1] = name_len; 1070 memcpy(buf + 2, name, name_len); 1071 tmplen = 2 + name_len; 1072 buf[tmplen++] = '\0'; 1073 1074 for (t = 0; t < len; t++) { 1075 stq_be_p(buf + tmplen, start_list[t]); 1076 tmplen += 8; 1077 stq_be_p(buf + tmplen, length_list[t]); 1078 tmplen += 8; 1079 } 1080 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RAM_DISCARD, tmplen, buf); 1081 g_free(buf); 1082 } 1083 1084 /* Get the destination into a state where it can receive postcopy data. */ 1085 void qemu_savevm_send_postcopy_listen(QEMUFile *f) 1086 { 1087 trace_savevm_send_postcopy_listen(); 1088 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_LISTEN, 0, NULL); 1089 } 1090 1091 /* Kick the destination into running */ 1092 void qemu_savevm_send_postcopy_run(QEMUFile *f) 1093 { 1094 trace_savevm_send_postcopy_run(); 1095 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RUN, 0, NULL); 1096 } 1097 1098 void qemu_savevm_send_postcopy_resume(QEMUFile *f) 1099 { 1100 trace_savevm_send_postcopy_resume(); 1101 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RESUME, 0, NULL); 1102 } 1103 1104 void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name) 1105 { 1106 size_t len; 1107 char buf[256]; 1108 1109 trace_savevm_send_recv_bitmap(block_name); 1110 1111 buf[0] = len = strlen(block_name); 1112 memcpy(buf + 1, block_name, len); 1113 1114 qemu_savevm_command_send(f, MIG_CMD_RECV_BITMAP, len + 1, (uint8_t *)buf); 1115 } 1116 1117 bool qemu_savevm_state_blocked(Error **errp) 1118 { 1119 SaveStateEntry *se; 1120 1121 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1122 if (se->vmsd && se->vmsd->unmigratable) { 1123 error_setg(errp, "State blocked by non-migratable device '%s'", 1124 se->idstr); 1125 return true; 1126 } 1127 } 1128 return false; 1129 } 1130 1131 void qemu_savevm_state_header(QEMUFile *f) 1132 { 1133 trace_savevm_state_header(); 1134 qemu_put_be32(f, QEMU_VM_FILE_MAGIC); 1135 qemu_put_be32(f, QEMU_VM_FILE_VERSION); 1136 1137 if (migrate_get_current()->send_configuration) { 1138 qemu_put_byte(f, QEMU_VM_CONFIGURATION); 1139 vmstate_save_state(f, &vmstate_configuration, &savevm_state, 0); 1140 } 1141 } 1142 1143 bool qemu_savevm_state_guest_unplug_pending(void) 1144 { 1145 SaveStateEntry *se; 1146 1147 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1148 if (se->vmsd && se->vmsd->dev_unplug_pending && 1149 se->vmsd->dev_unplug_pending(se->opaque)) { 1150 return true; 1151 } 1152 } 1153 1154 return false; 1155 } 1156 1157 void qemu_savevm_state_setup(QEMUFile *f) 1158 { 1159 SaveStateEntry *se; 1160 Error *local_err = NULL; 1161 int ret; 1162 1163 trace_savevm_state_setup(); 1164 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1165 if (!se->ops || !se->ops->save_setup) { 1166 continue; 1167 } 1168 if (se->ops->is_active) { 1169 if (!se->ops->is_active(se->opaque)) { 1170 continue; 1171 } 1172 } 1173 save_section_header(f, se, QEMU_VM_SECTION_START); 1174 1175 ret = se->ops->save_setup(f, se->opaque); 1176 save_section_footer(f, se); 1177 if (ret < 0) { 1178 qemu_file_set_error(f, ret); 1179 break; 1180 } 1181 } 1182 1183 if (precopy_notify(PRECOPY_NOTIFY_SETUP, &local_err)) { 1184 error_report_err(local_err); 1185 } 1186 } 1187 1188 int qemu_savevm_state_resume_prepare(MigrationState *s) 1189 { 1190 SaveStateEntry *se; 1191 int ret; 1192 1193 trace_savevm_state_resume_prepare(); 1194 1195 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1196 if (!se->ops || !se->ops->resume_prepare) { 1197 continue; 1198 } 1199 if (se->ops->is_active) { 1200 if (!se->ops->is_active(se->opaque)) { 1201 continue; 1202 } 1203 } 1204 ret = se->ops->resume_prepare(s, se->opaque); 1205 if (ret < 0) { 1206 return ret; 1207 } 1208 } 1209 1210 return 0; 1211 } 1212 1213 /* 1214 * this function has three return values: 1215 * negative: there was one error, and we have -errno. 1216 * 0 : We haven't finished, caller have to go again 1217 * 1 : We have finished, we can go to complete phase 1218 */ 1219 int qemu_savevm_state_iterate(QEMUFile *f, bool postcopy) 1220 { 1221 SaveStateEntry *se; 1222 int ret = 1; 1223 1224 trace_savevm_state_iterate(); 1225 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1226 if (!se->ops || !se->ops->save_live_iterate) { 1227 continue; 1228 } 1229 if (se->ops->is_active && 1230 !se->ops->is_active(se->opaque)) { 1231 continue; 1232 } 1233 if (se->ops->is_active_iterate && 1234 !se->ops->is_active_iterate(se->opaque)) { 1235 continue; 1236 } 1237 /* 1238 * In the postcopy phase, any device that doesn't know how to 1239 * do postcopy should have saved it's state in the _complete 1240 * call that's already run, it might get confused if we call 1241 * iterate afterwards. 1242 */ 1243 if (postcopy && 1244 !(se->ops->has_postcopy && se->ops->has_postcopy(se->opaque))) { 1245 continue; 1246 } 1247 if (qemu_file_rate_limit(f)) { 1248 return 0; 1249 } 1250 trace_savevm_section_start(se->idstr, se->section_id); 1251 1252 save_section_header(f, se, QEMU_VM_SECTION_PART); 1253 1254 ret = se->ops->save_live_iterate(f, se->opaque); 1255 trace_savevm_section_end(se->idstr, se->section_id, ret); 1256 save_section_footer(f, se); 1257 1258 if (ret < 0) { 1259 error_report("failed to save SaveStateEntry with id(name): %d(%s)", 1260 se->section_id, se->idstr); 1261 qemu_file_set_error(f, ret); 1262 } 1263 if (ret <= 0) { 1264 /* Do not proceed to the next vmstate before this one reported 1265 completion of the current stage. This serializes the migration 1266 and reduces the probability that a faster changing state is 1267 synchronized over and over again. */ 1268 break; 1269 } 1270 } 1271 return ret; 1272 } 1273 1274 static bool should_send_vmdesc(void) 1275 { 1276 MachineState *machine = MACHINE(qdev_get_machine()); 1277 bool in_postcopy = migration_in_postcopy(); 1278 return !machine->suppress_vmdesc && !in_postcopy; 1279 } 1280 1281 /* 1282 * Calls the save_live_complete_postcopy methods 1283 * causing the last few pages to be sent immediately and doing any associated 1284 * cleanup. 1285 * Note postcopy also calls qemu_savevm_state_complete_precopy to complete 1286 * all the other devices, but that happens at the point we switch to postcopy. 1287 */ 1288 void qemu_savevm_state_complete_postcopy(QEMUFile *f) 1289 { 1290 SaveStateEntry *se; 1291 int ret; 1292 1293 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1294 if (!se->ops || !se->ops->save_live_complete_postcopy) { 1295 continue; 1296 } 1297 if (se->ops->is_active) { 1298 if (!se->ops->is_active(se->opaque)) { 1299 continue; 1300 } 1301 } 1302 trace_savevm_section_start(se->idstr, se->section_id); 1303 /* Section type */ 1304 qemu_put_byte(f, QEMU_VM_SECTION_END); 1305 qemu_put_be32(f, se->section_id); 1306 1307 ret = se->ops->save_live_complete_postcopy(f, se->opaque); 1308 trace_savevm_section_end(se->idstr, se->section_id, ret); 1309 save_section_footer(f, se); 1310 if (ret < 0) { 1311 qemu_file_set_error(f, ret); 1312 return; 1313 } 1314 } 1315 1316 qemu_put_byte(f, QEMU_VM_EOF); 1317 qemu_fflush(f); 1318 } 1319 1320 static 1321 int qemu_savevm_state_complete_precopy_iterable(QEMUFile *f, bool in_postcopy) 1322 { 1323 SaveStateEntry *se; 1324 int ret; 1325 1326 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1327 if (!se->ops || 1328 (in_postcopy && se->ops->has_postcopy && 1329 se->ops->has_postcopy(se->opaque)) || 1330 !se->ops->save_live_complete_precopy) { 1331 continue; 1332 } 1333 1334 if (se->ops->is_active) { 1335 if (!se->ops->is_active(se->opaque)) { 1336 continue; 1337 } 1338 } 1339 trace_savevm_section_start(se->idstr, se->section_id); 1340 1341 save_section_header(f, se, QEMU_VM_SECTION_END); 1342 1343 ret = se->ops->save_live_complete_precopy(f, se->opaque); 1344 trace_savevm_section_end(se->idstr, se->section_id, ret); 1345 save_section_footer(f, se); 1346 if (ret < 0) { 1347 qemu_file_set_error(f, ret); 1348 return -1; 1349 } 1350 } 1351 1352 return 0; 1353 } 1354 1355 static 1356 int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f, 1357 bool in_postcopy, 1358 bool inactivate_disks) 1359 { 1360 g_autoptr(QJSON) vmdesc = NULL; 1361 int vmdesc_len; 1362 SaveStateEntry *se; 1363 int ret; 1364 1365 vmdesc = qjson_new(); 1366 json_prop_int(vmdesc, "page_size", qemu_target_page_size()); 1367 json_start_array(vmdesc, "devices"); 1368 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1369 1370 if ((!se->ops || !se->ops->save_state) && !se->vmsd) { 1371 continue; 1372 } 1373 if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) { 1374 trace_savevm_section_skip(se->idstr, se->section_id); 1375 continue; 1376 } 1377 1378 trace_savevm_section_start(se->idstr, se->section_id); 1379 1380 json_start_object(vmdesc, NULL); 1381 json_prop_str(vmdesc, "name", se->idstr); 1382 json_prop_int(vmdesc, "instance_id", se->instance_id); 1383 1384 save_section_header(f, se, QEMU_VM_SECTION_FULL); 1385 ret = vmstate_save(f, se, vmdesc); 1386 if (ret) { 1387 qemu_file_set_error(f, ret); 1388 return ret; 1389 } 1390 trace_savevm_section_end(se->idstr, se->section_id, 0); 1391 save_section_footer(f, se); 1392 1393 json_end_object(vmdesc); 1394 } 1395 1396 if (inactivate_disks) { 1397 /* Inactivate before sending QEMU_VM_EOF so that the 1398 * bdrv_invalidate_cache_all() on the other end won't fail. */ 1399 ret = bdrv_inactivate_all(); 1400 if (ret) { 1401 error_report("%s: bdrv_inactivate_all() failed (%d)", 1402 __func__, ret); 1403 qemu_file_set_error(f, ret); 1404 return ret; 1405 } 1406 } 1407 if (!in_postcopy) { 1408 /* Postcopy stream will still be going */ 1409 qemu_put_byte(f, QEMU_VM_EOF); 1410 } 1411 1412 json_end_array(vmdesc); 1413 qjson_finish(vmdesc); 1414 vmdesc_len = strlen(qjson_get_str(vmdesc)); 1415 1416 if (should_send_vmdesc()) { 1417 qemu_put_byte(f, QEMU_VM_VMDESCRIPTION); 1418 qemu_put_be32(f, vmdesc_len); 1419 qemu_put_buffer(f, (uint8_t *)qjson_get_str(vmdesc), vmdesc_len); 1420 } 1421 1422 return 0; 1423 } 1424 1425 int qemu_savevm_state_complete_precopy(QEMUFile *f, bool iterable_only, 1426 bool inactivate_disks) 1427 { 1428 int ret; 1429 Error *local_err = NULL; 1430 bool in_postcopy = migration_in_postcopy(); 1431 1432 if (precopy_notify(PRECOPY_NOTIFY_COMPLETE, &local_err)) { 1433 error_report_err(local_err); 1434 } 1435 1436 trace_savevm_state_complete_precopy(); 1437 1438 cpu_synchronize_all_states(); 1439 1440 if (!in_postcopy || iterable_only) { 1441 ret = qemu_savevm_state_complete_precopy_iterable(f, in_postcopy); 1442 if (ret) { 1443 return ret; 1444 } 1445 } 1446 1447 if (iterable_only) { 1448 goto flush; 1449 } 1450 1451 ret = qemu_savevm_state_complete_precopy_non_iterable(f, in_postcopy, 1452 inactivate_disks); 1453 if (ret) { 1454 return ret; 1455 } 1456 1457 flush: 1458 qemu_fflush(f); 1459 return 0; 1460 } 1461 1462 /* Give an estimate of the amount left to be transferred, 1463 * the result is split into the amount for units that can and 1464 * for units that can't do postcopy. 1465 */ 1466 void qemu_savevm_state_pending(QEMUFile *f, uint64_t threshold_size, 1467 uint64_t *res_precopy_only, 1468 uint64_t *res_compatible, 1469 uint64_t *res_postcopy_only) 1470 { 1471 SaveStateEntry *se; 1472 1473 *res_precopy_only = 0; 1474 *res_compatible = 0; 1475 *res_postcopy_only = 0; 1476 1477 1478 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1479 if (!se->ops || !se->ops->save_live_pending) { 1480 continue; 1481 } 1482 if (se->ops->is_active) { 1483 if (!se->ops->is_active(se->opaque)) { 1484 continue; 1485 } 1486 } 1487 se->ops->save_live_pending(f, se->opaque, threshold_size, 1488 res_precopy_only, res_compatible, 1489 res_postcopy_only); 1490 } 1491 } 1492 1493 void qemu_savevm_state_cleanup(void) 1494 { 1495 SaveStateEntry *se; 1496 Error *local_err = NULL; 1497 1498 if (precopy_notify(PRECOPY_NOTIFY_CLEANUP, &local_err)) { 1499 error_report_err(local_err); 1500 } 1501 1502 trace_savevm_state_cleanup(); 1503 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1504 if (se->ops && se->ops->save_cleanup) { 1505 se->ops->save_cleanup(se->opaque); 1506 } 1507 } 1508 } 1509 1510 static int qemu_savevm_state(QEMUFile *f, Error **errp) 1511 { 1512 int ret; 1513 MigrationState *ms = migrate_get_current(); 1514 MigrationStatus status; 1515 1516 if (migration_is_running(ms->state)) { 1517 error_setg(errp, QERR_MIGRATION_ACTIVE); 1518 return -EINVAL; 1519 } 1520 1521 if (migrate_use_block()) { 1522 error_setg(errp, "Block migration and snapshots are incompatible"); 1523 return -EINVAL; 1524 } 1525 1526 migrate_init(ms); 1527 memset(&ram_counters, 0, sizeof(ram_counters)); 1528 ms->to_dst_file = f; 1529 1530 qemu_mutex_unlock_iothread(); 1531 qemu_savevm_state_header(f); 1532 qemu_savevm_state_setup(f); 1533 qemu_mutex_lock_iothread(); 1534 1535 while (qemu_file_get_error(f) == 0) { 1536 if (qemu_savevm_state_iterate(f, false) > 0) { 1537 break; 1538 } 1539 } 1540 1541 ret = qemu_file_get_error(f); 1542 if (ret == 0) { 1543 qemu_savevm_state_complete_precopy(f, false, false); 1544 ret = qemu_file_get_error(f); 1545 } 1546 qemu_savevm_state_cleanup(); 1547 if (ret != 0) { 1548 error_setg_errno(errp, -ret, "Error while writing VM state"); 1549 } 1550 1551 if (ret != 0) { 1552 status = MIGRATION_STATUS_FAILED; 1553 } else { 1554 status = MIGRATION_STATUS_COMPLETED; 1555 } 1556 migrate_set_state(&ms->state, MIGRATION_STATUS_SETUP, status); 1557 1558 /* f is outer parameter, it should not stay in global migration state after 1559 * this function finished */ 1560 ms->to_dst_file = NULL; 1561 1562 return ret; 1563 } 1564 1565 void qemu_savevm_live_state(QEMUFile *f) 1566 { 1567 /* save QEMU_VM_SECTION_END section */ 1568 qemu_savevm_state_complete_precopy(f, true, false); 1569 qemu_put_byte(f, QEMU_VM_EOF); 1570 } 1571 1572 int qemu_save_device_state(QEMUFile *f) 1573 { 1574 SaveStateEntry *se; 1575 1576 if (!migration_in_colo_state()) { 1577 qemu_put_be32(f, QEMU_VM_FILE_MAGIC); 1578 qemu_put_be32(f, QEMU_VM_FILE_VERSION); 1579 } 1580 cpu_synchronize_all_states(); 1581 1582 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1583 int ret; 1584 1585 if (se->is_ram) { 1586 continue; 1587 } 1588 if ((!se->ops || !se->ops->save_state) && !se->vmsd) { 1589 continue; 1590 } 1591 if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) { 1592 continue; 1593 } 1594 1595 save_section_header(f, se, QEMU_VM_SECTION_FULL); 1596 1597 ret = vmstate_save(f, se, NULL); 1598 if (ret) { 1599 return ret; 1600 } 1601 1602 save_section_footer(f, se); 1603 } 1604 1605 qemu_put_byte(f, QEMU_VM_EOF); 1606 1607 return qemu_file_get_error(f); 1608 } 1609 1610 static SaveStateEntry *find_se(const char *idstr, uint32_t instance_id) 1611 { 1612 SaveStateEntry *se; 1613 1614 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1615 if (!strcmp(se->idstr, idstr) && 1616 (instance_id == se->instance_id || 1617 instance_id == se->alias_id)) 1618 return se; 1619 /* Migrating from an older version? */ 1620 if (strstr(se->idstr, idstr) && se->compat) { 1621 if (!strcmp(se->compat->idstr, idstr) && 1622 (instance_id == se->compat->instance_id || 1623 instance_id == se->alias_id)) 1624 return se; 1625 } 1626 } 1627 return NULL; 1628 } 1629 1630 enum LoadVMExitCodes { 1631 /* Allow a command to quit all layers of nested loadvm loops */ 1632 LOADVM_QUIT = 1, 1633 }; 1634 1635 /* ------ incoming postcopy messages ------ */ 1636 /* 'advise' arrives before any transfers just to tell us that a postcopy 1637 * *might* happen - it might be skipped if precopy transferred everything 1638 * quickly. 1639 */ 1640 static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis, 1641 uint16_t len) 1642 { 1643 PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_ADVISE); 1644 uint64_t remote_pagesize_summary, local_pagesize_summary, remote_tps; 1645 Error *local_err = NULL; 1646 1647 trace_loadvm_postcopy_handle_advise(); 1648 if (ps != POSTCOPY_INCOMING_NONE) { 1649 error_report("CMD_POSTCOPY_ADVISE in wrong postcopy state (%d)", ps); 1650 return -1; 1651 } 1652 1653 switch (len) { 1654 case 0: 1655 if (migrate_postcopy_ram()) { 1656 error_report("RAM postcopy is enabled but have 0 byte advise"); 1657 return -EINVAL; 1658 } 1659 return 0; 1660 case 8 + 8: 1661 if (!migrate_postcopy_ram()) { 1662 error_report("RAM postcopy is disabled but have 16 byte advise"); 1663 return -EINVAL; 1664 } 1665 break; 1666 default: 1667 error_report("CMD_POSTCOPY_ADVISE invalid length (%d)", len); 1668 return -EINVAL; 1669 } 1670 1671 if (!postcopy_ram_supported_by_host(mis)) { 1672 postcopy_state_set(POSTCOPY_INCOMING_NONE); 1673 return -1; 1674 } 1675 1676 remote_pagesize_summary = qemu_get_be64(mis->from_src_file); 1677 local_pagesize_summary = ram_pagesize_summary(); 1678 1679 if (remote_pagesize_summary != local_pagesize_summary) { 1680 /* 1681 * This detects two potential causes of mismatch: 1682 * a) A mismatch in host page sizes 1683 * Some combinations of mismatch are probably possible but it gets 1684 * a bit more complicated. In particular we need to place whole 1685 * host pages on the dest at once, and we need to ensure that we 1686 * handle dirtying to make sure we never end up sending part of 1687 * a hostpage on it's own. 1688 * b) The use of different huge page sizes on source/destination 1689 * a more fine grain test is performed during RAM block migration 1690 * but this test here causes a nice early clear failure, and 1691 * also fails when passed to an older qemu that doesn't 1692 * do huge pages. 1693 */ 1694 error_report("Postcopy needs matching RAM page sizes (s=%" PRIx64 1695 " d=%" PRIx64 ")", 1696 remote_pagesize_summary, local_pagesize_summary); 1697 return -1; 1698 } 1699 1700 remote_tps = qemu_get_be64(mis->from_src_file); 1701 if (remote_tps != qemu_target_page_size()) { 1702 /* 1703 * Again, some differences could be dealt with, but for now keep it 1704 * simple. 1705 */ 1706 error_report("Postcopy needs matching target page sizes (s=%d d=%zd)", 1707 (int)remote_tps, qemu_target_page_size()); 1708 return -1; 1709 } 1710 1711 if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_ADVISE, &local_err)) { 1712 error_report_err(local_err); 1713 return -1; 1714 } 1715 1716 if (ram_postcopy_incoming_init(mis)) { 1717 return -1; 1718 } 1719 1720 return 0; 1721 } 1722 1723 /* After postcopy we will be told to throw some pages away since they're 1724 * dirty and will have to be demand fetched. Must happen before CPU is 1725 * started. 1726 * There can be 0..many of these messages, each encoding multiple pages. 1727 */ 1728 static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis, 1729 uint16_t len) 1730 { 1731 int tmp; 1732 char ramid[256]; 1733 PostcopyState ps = postcopy_state_get(); 1734 1735 trace_loadvm_postcopy_ram_handle_discard(); 1736 1737 switch (ps) { 1738 case POSTCOPY_INCOMING_ADVISE: 1739 /* 1st discard */ 1740 tmp = postcopy_ram_prepare_discard(mis); 1741 if (tmp) { 1742 return tmp; 1743 } 1744 break; 1745 1746 case POSTCOPY_INCOMING_DISCARD: 1747 /* Expected state */ 1748 break; 1749 1750 default: 1751 error_report("CMD_POSTCOPY_RAM_DISCARD in wrong postcopy state (%d)", 1752 ps); 1753 return -1; 1754 } 1755 /* We're expecting a 1756 * Version (0) 1757 * a RAM ID string (length byte, name, 0 term) 1758 * then at least 1 16 byte chunk 1759 */ 1760 if (len < (1 + 1 + 1 + 1 + 2 * 8)) { 1761 error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len); 1762 return -1; 1763 } 1764 1765 tmp = qemu_get_byte(mis->from_src_file); 1766 if (tmp != postcopy_ram_discard_version) { 1767 error_report("CMD_POSTCOPY_RAM_DISCARD invalid version (%d)", tmp); 1768 return -1; 1769 } 1770 1771 if (!qemu_get_counted_string(mis->from_src_file, ramid)) { 1772 error_report("CMD_POSTCOPY_RAM_DISCARD Failed to read RAMBlock ID"); 1773 return -1; 1774 } 1775 tmp = qemu_get_byte(mis->from_src_file); 1776 if (tmp != 0) { 1777 error_report("CMD_POSTCOPY_RAM_DISCARD missing nil (%d)", tmp); 1778 return -1; 1779 } 1780 1781 len -= 3 + strlen(ramid); 1782 if (len % 16) { 1783 error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len); 1784 return -1; 1785 } 1786 trace_loadvm_postcopy_ram_handle_discard_header(ramid, len); 1787 while (len) { 1788 uint64_t start_addr, block_length; 1789 start_addr = qemu_get_be64(mis->from_src_file); 1790 block_length = qemu_get_be64(mis->from_src_file); 1791 1792 len -= 16; 1793 int ret = ram_discard_range(ramid, start_addr, block_length); 1794 if (ret) { 1795 return ret; 1796 } 1797 } 1798 trace_loadvm_postcopy_ram_handle_discard_end(); 1799 1800 return 0; 1801 } 1802 1803 /* 1804 * Triggered by a postcopy_listen command; this thread takes over reading 1805 * the input stream, leaving the main thread free to carry on loading the rest 1806 * of the device state (from RAM). 1807 * (TODO:This could do with being in a postcopy file - but there again it's 1808 * just another input loop, not that postcopy specific) 1809 */ 1810 static void *postcopy_ram_listen_thread(void *opaque) 1811 { 1812 MigrationIncomingState *mis = migration_incoming_get_current(); 1813 QEMUFile *f = mis->from_src_file; 1814 int load_res; 1815 MigrationState *migr = migrate_get_current(); 1816 1817 object_ref(OBJECT(migr)); 1818 1819 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, 1820 MIGRATION_STATUS_POSTCOPY_ACTIVE); 1821 qemu_sem_post(&mis->listen_thread_sem); 1822 trace_postcopy_ram_listen_thread_start(); 1823 1824 rcu_register_thread(); 1825 /* 1826 * Because we're a thread and not a coroutine we can't yield 1827 * in qemu_file, and thus we must be blocking now. 1828 */ 1829 qemu_file_set_blocking(f, true); 1830 load_res = qemu_loadvm_state_main(f, mis); 1831 1832 /* 1833 * This is tricky, but, mis->from_src_file can change after it 1834 * returns, when postcopy recovery happened. In the future, we may 1835 * want a wrapper for the QEMUFile handle. 1836 */ 1837 f = mis->from_src_file; 1838 1839 /* And non-blocking again so we don't block in any cleanup */ 1840 qemu_file_set_blocking(f, false); 1841 1842 trace_postcopy_ram_listen_thread_exit(); 1843 if (load_res < 0) { 1844 qemu_file_set_error(f, load_res); 1845 dirty_bitmap_mig_cancel_incoming(); 1846 if (postcopy_state_get() == POSTCOPY_INCOMING_RUNNING && 1847 !migrate_postcopy_ram() && migrate_dirty_bitmaps()) 1848 { 1849 error_report("%s: loadvm failed during postcopy: %d. All states " 1850 "are migrated except dirty bitmaps. Some dirty " 1851 "bitmaps may be lost, and present migrated dirty " 1852 "bitmaps are correctly migrated and valid.", 1853 __func__, load_res); 1854 load_res = 0; /* prevent further exit() */ 1855 } else { 1856 error_report("%s: loadvm failed: %d", __func__, load_res); 1857 migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, 1858 MIGRATION_STATUS_FAILED); 1859 } 1860 } 1861 if (load_res >= 0) { 1862 /* 1863 * This looks good, but it's possible that the device loading in the 1864 * main thread hasn't finished yet, and so we might not be in 'RUN' 1865 * state yet; wait for the end of the main thread. 1866 */ 1867 qemu_event_wait(&mis->main_thread_load_event); 1868 } 1869 postcopy_ram_incoming_cleanup(mis); 1870 1871 if (load_res < 0) { 1872 /* 1873 * If something went wrong then we have a bad state so exit; 1874 * depending how far we got it might be possible at this point 1875 * to leave the guest running and fire MCEs for pages that never 1876 * arrived as a desperate recovery step. 1877 */ 1878 rcu_unregister_thread(); 1879 exit(EXIT_FAILURE); 1880 } 1881 1882 migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, 1883 MIGRATION_STATUS_COMPLETED); 1884 /* 1885 * If everything has worked fine, then the main thread has waited 1886 * for us to start, and we're the last use of the mis. 1887 * (If something broke then qemu will have to exit anyway since it's 1888 * got a bad migration state). 1889 */ 1890 migration_incoming_state_destroy(); 1891 qemu_loadvm_state_cleanup(); 1892 1893 rcu_unregister_thread(); 1894 mis->have_listen_thread = false; 1895 postcopy_state_set(POSTCOPY_INCOMING_END); 1896 1897 object_unref(OBJECT(migr)); 1898 1899 return NULL; 1900 } 1901 1902 /* After this message we must be able to immediately receive postcopy data */ 1903 static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis) 1904 { 1905 PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_LISTENING); 1906 trace_loadvm_postcopy_handle_listen(); 1907 Error *local_err = NULL; 1908 1909 if (ps != POSTCOPY_INCOMING_ADVISE && ps != POSTCOPY_INCOMING_DISCARD) { 1910 error_report("CMD_POSTCOPY_LISTEN in wrong postcopy state (%d)", ps); 1911 return -1; 1912 } 1913 if (ps == POSTCOPY_INCOMING_ADVISE) { 1914 /* 1915 * A rare case, we entered listen without having to do any discards, 1916 * so do the setup that's normally done at the time of the 1st discard. 1917 */ 1918 if (migrate_postcopy_ram()) { 1919 postcopy_ram_prepare_discard(mis); 1920 } 1921 } 1922 1923 /* 1924 * Sensitise RAM - can now generate requests for blocks that don't exist 1925 * However, at this point the CPU shouldn't be running, and the IO 1926 * shouldn't be doing anything yet so don't actually expect requests 1927 */ 1928 if (migrate_postcopy_ram()) { 1929 if (postcopy_ram_incoming_setup(mis)) { 1930 postcopy_ram_incoming_cleanup(mis); 1931 return -1; 1932 } 1933 } 1934 1935 if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_LISTEN, &local_err)) { 1936 error_report_err(local_err); 1937 return -1; 1938 } 1939 1940 mis->have_listen_thread = true; 1941 /* Start up the listening thread and wait for it to signal ready */ 1942 qemu_sem_init(&mis->listen_thread_sem, 0); 1943 qemu_thread_create(&mis->listen_thread, "postcopy/listen", 1944 postcopy_ram_listen_thread, NULL, 1945 QEMU_THREAD_DETACHED); 1946 qemu_sem_wait(&mis->listen_thread_sem); 1947 qemu_sem_destroy(&mis->listen_thread_sem); 1948 1949 return 0; 1950 } 1951 1952 static void loadvm_postcopy_handle_run_bh(void *opaque) 1953 { 1954 Error *local_err = NULL; 1955 MigrationIncomingState *mis = opaque; 1956 1957 /* TODO we should move all of this lot into postcopy_ram.c or a shared code 1958 * in migration.c 1959 */ 1960 cpu_synchronize_all_post_init(); 1961 1962 qemu_announce_self(&mis->announce_timer, migrate_announce_params()); 1963 1964 /* Make sure all file formats flush their mutable metadata. 1965 * If we get an error here, just don't restart the VM yet. */ 1966 bdrv_invalidate_cache_all(&local_err); 1967 if (local_err) { 1968 error_report_err(local_err); 1969 local_err = NULL; 1970 autostart = false; 1971 } 1972 1973 trace_loadvm_postcopy_handle_run_cpu_sync(); 1974 1975 trace_loadvm_postcopy_handle_run_vmstart(); 1976 1977 dirty_bitmap_mig_before_vm_start(); 1978 1979 if (autostart) { 1980 /* Hold onto your hats, starting the CPU */ 1981 vm_start(); 1982 } else { 1983 /* leave it paused and let management decide when to start the CPU */ 1984 runstate_set(RUN_STATE_PAUSED); 1985 } 1986 1987 qemu_bh_delete(mis->bh); 1988 } 1989 1990 /* After all discards we can start running and asking for pages */ 1991 static int loadvm_postcopy_handle_run(MigrationIncomingState *mis) 1992 { 1993 PostcopyState ps = postcopy_state_get(); 1994 1995 trace_loadvm_postcopy_handle_run(); 1996 if (ps != POSTCOPY_INCOMING_LISTENING) { 1997 error_report("CMD_POSTCOPY_RUN in wrong postcopy state (%d)", ps); 1998 return -1; 1999 } 2000 2001 postcopy_state_set(POSTCOPY_INCOMING_RUNNING); 2002 mis->bh = qemu_bh_new(loadvm_postcopy_handle_run_bh, mis); 2003 qemu_bh_schedule(mis->bh); 2004 2005 /* We need to finish reading the stream from the package 2006 * and also stop reading anything more from the stream that loaded the 2007 * package (since it's now being read by the listener thread). 2008 * LOADVM_QUIT will quit all the layers of nested loadvm loops. 2009 */ 2010 return LOADVM_QUIT; 2011 } 2012 2013 static int loadvm_postcopy_handle_resume(MigrationIncomingState *mis) 2014 { 2015 if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) { 2016 error_report("%s: illegal resume received", __func__); 2017 /* Don't fail the load, only for this. */ 2018 return 0; 2019 } 2020 2021 /* 2022 * This means source VM is ready to resume the postcopy migration. 2023 * It's time to switch state and release the fault thread to 2024 * continue service page faults. 2025 */ 2026 migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_RECOVER, 2027 MIGRATION_STATUS_POSTCOPY_ACTIVE); 2028 qemu_sem_post(&mis->postcopy_pause_sem_fault); 2029 2030 trace_loadvm_postcopy_handle_resume(); 2031 2032 /* Tell source that "we are ready" */ 2033 migrate_send_rp_resume_ack(mis, MIGRATION_RESUME_ACK_VALUE); 2034 2035 return 0; 2036 } 2037 2038 /** 2039 * Immediately following this command is a blob of data containing an embedded 2040 * chunk of migration stream; read it and load it. 2041 * 2042 * @mis: Incoming state 2043 * @length: Length of packaged data to read 2044 * 2045 * Returns: Negative values on error 2046 * 2047 */ 2048 static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) 2049 { 2050 int ret; 2051 size_t length; 2052 QIOChannelBuffer *bioc; 2053 2054 length = qemu_get_be32(mis->from_src_file); 2055 trace_loadvm_handle_cmd_packaged(length); 2056 2057 if (length > MAX_VM_CMD_PACKAGED_SIZE) { 2058 error_report("Unreasonably large packaged state: %zu", length); 2059 return -1; 2060 } 2061 2062 bioc = qio_channel_buffer_new(length); 2063 qio_channel_set_name(QIO_CHANNEL(bioc), "migration-loadvm-buffer"); 2064 ret = qemu_get_buffer(mis->from_src_file, 2065 bioc->data, 2066 length); 2067 if (ret != length) { 2068 object_unref(OBJECT(bioc)); 2069 error_report("CMD_PACKAGED: Buffer receive fail ret=%d length=%zu", 2070 ret, length); 2071 return (ret < 0) ? ret : -EAGAIN; 2072 } 2073 bioc->usage += length; 2074 trace_loadvm_handle_cmd_packaged_received(ret); 2075 2076 QEMUFile *packf = qemu_fopen_channel_input(QIO_CHANNEL(bioc)); 2077 2078 ret = qemu_loadvm_state_main(packf, mis); 2079 trace_loadvm_handle_cmd_packaged_main(ret); 2080 qemu_fclose(packf); 2081 object_unref(OBJECT(bioc)); 2082 2083 return ret; 2084 } 2085 2086 /* 2087 * Handle request that source requests for recved_bitmap on 2088 * destination. Payload format: 2089 * 2090 * len (1 byte) + ramblock_name (<255 bytes) 2091 */ 2092 static int loadvm_handle_recv_bitmap(MigrationIncomingState *mis, 2093 uint16_t len) 2094 { 2095 QEMUFile *file = mis->from_src_file; 2096 RAMBlock *rb; 2097 char block_name[256]; 2098 size_t cnt; 2099 2100 cnt = qemu_get_counted_string(file, block_name); 2101 if (!cnt) { 2102 error_report("%s: failed to read block name", __func__); 2103 return -EINVAL; 2104 } 2105 2106 /* Validate before using the data */ 2107 if (qemu_file_get_error(file)) { 2108 return qemu_file_get_error(file); 2109 } 2110 2111 if (len != cnt + 1) { 2112 error_report("%s: invalid payload length (%d)", __func__, len); 2113 return -EINVAL; 2114 } 2115 2116 rb = qemu_ram_block_by_name(block_name); 2117 if (!rb) { 2118 error_report("%s: block '%s' not found", __func__, block_name); 2119 return -EINVAL; 2120 } 2121 2122 migrate_send_rp_recv_bitmap(mis, block_name); 2123 2124 trace_loadvm_handle_recv_bitmap(block_name); 2125 2126 return 0; 2127 } 2128 2129 static int loadvm_process_enable_colo(MigrationIncomingState *mis) 2130 { 2131 int ret = migration_incoming_enable_colo(); 2132 2133 if (!ret) { 2134 ret = colo_init_ram_cache(); 2135 if (ret) { 2136 migration_incoming_disable_colo(); 2137 } 2138 } 2139 return ret; 2140 } 2141 2142 /* 2143 * Process an incoming 'QEMU_VM_COMMAND' 2144 * 0 just a normal return 2145 * LOADVM_QUIT All good, but exit the loop 2146 * <0 Error 2147 */ 2148 static int loadvm_process_command(QEMUFile *f) 2149 { 2150 MigrationIncomingState *mis = migration_incoming_get_current(); 2151 uint16_t cmd; 2152 uint16_t len; 2153 uint32_t tmp32; 2154 2155 cmd = qemu_get_be16(f); 2156 len = qemu_get_be16(f); 2157 2158 /* Check validity before continue processing of cmds */ 2159 if (qemu_file_get_error(f)) { 2160 return qemu_file_get_error(f); 2161 } 2162 2163 trace_loadvm_process_command(cmd, len); 2164 if (cmd >= MIG_CMD_MAX || cmd == MIG_CMD_INVALID) { 2165 error_report("MIG_CMD 0x%x unknown (len 0x%x)", cmd, len); 2166 return -EINVAL; 2167 } 2168 2169 if (mig_cmd_args[cmd].len != -1 && mig_cmd_args[cmd].len != len) { 2170 error_report("%s received with bad length - expecting %zu, got %d", 2171 mig_cmd_args[cmd].name, 2172 (size_t)mig_cmd_args[cmd].len, len); 2173 return -ERANGE; 2174 } 2175 2176 switch (cmd) { 2177 case MIG_CMD_OPEN_RETURN_PATH: 2178 if (mis->to_src_file) { 2179 error_report("CMD_OPEN_RETURN_PATH called when RP already open"); 2180 /* Not really a problem, so don't give up */ 2181 return 0; 2182 } 2183 mis->to_src_file = qemu_file_get_return_path(f); 2184 if (!mis->to_src_file) { 2185 error_report("CMD_OPEN_RETURN_PATH failed"); 2186 return -1; 2187 } 2188 break; 2189 2190 case MIG_CMD_PING: 2191 tmp32 = qemu_get_be32(f); 2192 trace_loadvm_process_command_ping(tmp32); 2193 if (!mis->to_src_file) { 2194 error_report("CMD_PING (0x%x) received with no return path", 2195 tmp32); 2196 return -1; 2197 } 2198 migrate_send_rp_pong(mis, tmp32); 2199 break; 2200 2201 case MIG_CMD_PACKAGED: 2202 return loadvm_handle_cmd_packaged(mis); 2203 2204 case MIG_CMD_POSTCOPY_ADVISE: 2205 return loadvm_postcopy_handle_advise(mis, len); 2206 2207 case MIG_CMD_POSTCOPY_LISTEN: 2208 return loadvm_postcopy_handle_listen(mis); 2209 2210 case MIG_CMD_POSTCOPY_RUN: 2211 return loadvm_postcopy_handle_run(mis); 2212 2213 case MIG_CMD_POSTCOPY_RAM_DISCARD: 2214 return loadvm_postcopy_ram_handle_discard(mis, len); 2215 2216 case MIG_CMD_POSTCOPY_RESUME: 2217 return loadvm_postcopy_handle_resume(mis); 2218 2219 case MIG_CMD_RECV_BITMAP: 2220 return loadvm_handle_recv_bitmap(mis, len); 2221 2222 case MIG_CMD_ENABLE_COLO: 2223 return loadvm_process_enable_colo(mis); 2224 } 2225 2226 return 0; 2227 } 2228 2229 /* 2230 * Read a footer off the wire and check that it matches the expected section 2231 * 2232 * Returns: true if the footer was good 2233 * false if there is a problem (and calls error_report to say why) 2234 */ 2235 static bool check_section_footer(QEMUFile *f, SaveStateEntry *se) 2236 { 2237 int ret; 2238 uint8_t read_mark; 2239 uint32_t read_section_id; 2240 2241 if (!migrate_get_current()->send_section_footer) { 2242 /* No footer to check */ 2243 return true; 2244 } 2245 2246 read_mark = qemu_get_byte(f); 2247 2248 ret = qemu_file_get_error(f); 2249 if (ret) { 2250 error_report("%s: Read section footer failed: %d", 2251 __func__, ret); 2252 return false; 2253 } 2254 2255 if (read_mark != QEMU_VM_SECTION_FOOTER) { 2256 error_report("Missing section footer for %s", se->idstr); 2257 return false; 2258 } 2259 2260 read_section_id = qemu_get_be32(f); 2261 if (read_section_id != se->load_section_id) { 2262 error_report("Mismatched section id in footer for %s -" 2263 " read 0x%x expected 0x%x", 2264 se->idstr, read_section_id, se->load_section_id); 2265 return false; 2266 } 2267 2268 /* All good */ 2269 return true; 2270 } 2271 2272 static int 2273 qemu_loadvm_section_start_full(QEMUFile *f, MigrationIncomingState *mis) 2274 { 2275 uint32_t instance_id, version_id, section_id; 2276 SaveStateEntry *se; 2277 char idstr[256]; 2278 int ret; 2279 2280 /* Read section start */ 2281 section_id = qemu_get_be32(f); 2282 if (!qemu_get_counted_string(f, idstr)) { 2283 error_report("Unable to read ID string for section %u", 2284 section_id); 2285 return -EINVAL; 2286 } 2287 instance_id = qemu_get_be32(f); 2288 version_id = qemu_get_be32(f); 2289 2290 ret = qemu_file_get_error(f); 2291 if (ret) { 2292 error_report("%s: Failed to read instance/version ID: %d", 2293 __func__, ret); 2294 return ret; 2295 } 2296 2297 trace_qemu_loadvm_state_section_startfull(section_id, idstr, 2298 instance_id, version_id); 2299 /* Find savevm section */ 2300 se = find_se(idstr, instance_id); 2301 if (se == NULL) { 2302 error_report("Unknown savevm section or instance '%s' %"PRIu32". " 2303 "Make sure that your current VM setup matches your " 2304 "saved VM setup, including any hotplugged devices", 2305 idstr, instance_id); 2306 return -EINVAL; 2307 } 2308 2309 /* Validate version */ 2310 if (version_id > se->version_id) { 2311 error_report("savevm: unsupported version %d for '%s' v%d", 2312 version_id, idstr, se->version_id); 2313 return -EINVAL; 2314 } 2315 se->load_version_id = version_id; 2316 se->load_section_id = section_id; 2317 2318 /* Validate if it is a device's state */ 2319 if (xen_enabled() && se->is_ram) { 2320 error_report("loadvm: %s RAM loading not allowed on Xen", idstr); 2321 return -EINVAL; 2322 } 2323 2324 ret = vmstate_load(f, se); 2325 if (ret < 0) { 2326 error_report("error while loading state for instance 0x%"PRIx32" of" 2327 " device '%s'", instance_id, idstr); 2328 return ret; 2329 } 2330 if (!check_section_footer(f, se)) { 2331 return -EINVAL; 2332 } 2333 2334 return 0; 2335 } 2336 2337 static int 2338 qemu_loadvm_section_part_end(QEMUFile *f, MigrationIncomingState *mis) 2339 { 2340 uint32_t section_id; 2341 SaveStateEntry *se; 2342 int ret; 2343 2344 section_id = qemu_get_be32(f); 2345 2346 ret = qemu_file_get_error(f); 2347 if (ret) { 2348 error_report("%s: Failed to read section ID: %d", 2349 __func__, ret); 2350 return ret; 2351 } 2352 2353 trace_qemu_loadvm_state_section_partend(section_id); 2354 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 2355 if (se->load_section_id == section_id) { 2356 break; 2357 } 2358 } 2359 if (se == NULL) { 2360 error_report("Unknown savevm section %d", section_id); 2361 return -EINVAL; 2362 } 2363 2364 ret = vmstate_load(f, se); 2365 if (ret < 0) { 2366 error_report("error while loading state section id %d(%s)", 2367 section_id, se->idstr); 2368 return ret; 2369 } 2370 if (!check_section_footer(f, se)) { 2371 return -EINVAL; 2372 } 2373 2374 return 0; 2375 } 2376 2377 static int qemu_loadvm_state_header(QEMUFile *f) 2378 { 2379 unsigned int v; 2380 int ret; 2381 2382 v = qemu_get_be32(f); 2383 if (v != QEMU_VM_FILE_MAGIC) { 2384 error_report("Not a migration stream"); 2385 return -EINVAL; 2386 } 2387 2388 v = qemu_get_be32(f); 2389 if (v == QEMU_VM_FILE_VERSION_COMPAT) { 2390 error_report("SaveVM v2 format is obsolete and don't work anymore"); 2391 return -ENOTSUP; 2392 } 2393 if (v != QEMU_VM_FILE_VERSION) { 2394 error_report("Unsupported migration stream version"); 2395 return -ENOTSUP; 2396 } 2397 2398 if (migrate_get_current()->send_configuration) { 2399 if (qemu_get_byte(f) != QEMU_VM_CONFIGURATION) { 2400 error_report("Configuration section missing"); 2401 qemu_loadvm_state_cleanup(); 2402 return -EINVAL; 2403 } 2404 ret = vmstate_load_state(f, &vmstate_configuration, &savevm_state, 0); 2405 2406 if (ret) { 2407 qemu_loadvm_state_cleanup(); 2408 return ret; 2409 } 2410 } 2411 return 0; 2412 } 2413 2414 static int qemu_loadvm_state_setup(QEMUFile *f) 2415 { 2416 SaveStateEntry *se; 2417 int ret; 2418 2419 trace_loadvm_state_setup(); 2420 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 2421 if (!se->ops || !se->ops->load_setup) { 2422 continue; 2423 } 2424 if (se->ops->is_active) { 2425 if (!se->ops->is_active(se->opaque)) { 2426 continue; 2427 } 2428 } 2429 2430 ret = se->ops->load_setup(f, se->opaque); 2431 if (ret < 0) { 2432 qemu_file_set_error(f, ret); 2433 error_report("Load state of device %s failed", se->idstr); 2434 return ret; 2435 } 2436 } 2437 return 0; 2438 } 2439 2440 void qemu_loadvm_state_cleanup(void) 2441 { 2442 SaveStateEntry *se; 2443 2444 trace_loadvm_state_cleanup(); 2445 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 2446 if (se->ops && se->ops->load_cleanup) { 2447 se->ops->load_cleanup(se->opaque); 2448 } 2449 } 2450 } 2451 2452 /* Return true if we should continue the migration, or false. */ 2453 static bool postcopy_pause_incoming(MigrationIncomingState *mis) 2454 { 2455 trace_postcopy_pause_incoming(); 2456 2457 assert(migrate_postcopy_ram()); 2458 2459 /* Clear the triggered bit to allow one recovery */ 2460 mis->postcopy_recover_triggered = false; 2461 2462 assert(mis->from_src_file); 2463 qemu_file_shutdown(mis->from_src_file); 2464 qemu_fclose(mis->from_src_file); 2465 mis->from_src_file = NULL; 2466 2467 assert(mis->to_src_file); 2468 qemu_file_shutdown(mis->to_src_file); 2469 qemu_mutex_lock(&mis->rp_mutex); 2470 qemu_fclose(mis->to_src_file); 2471 mis->to_src_file = NULL; 2472 qemu_mutex_unlock(&mis->rp_mutex); 2473 2474 migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, 2475 MIGRATION_STATUS_POSTCOPY_PAUSED); 2476 2477 /* Notify the fault thread for the invalidated file handle */ 2478 postcopy_fault_thread_notify(mis); 2479 2480 error_report("Detected IO failure for postcopy. " 2481 "Migration paused."); 2482 2483 while (mis->state == MIGRATION_STATUS_POSTCOPY_PAUSED) { 2484 qemu_sem_wait(&mis->postcopy_pause_sem_dst); 2485 } 2486 2487 trace_postcopy_pause_incoming_continued(); 2488 2489 return true; 2490 } 2491 2492 int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis) 2493 { 2494 uint8_t section_type; 2495 int ret = 0; 2496 2497 retry: 2498 while (true) { 2499 section_type = qemu_get_byte(f); 2500 2501 if (qemu_file_get_error(f)) { 2502 ret = qemu_file_get_error(f); 2503 break; 2504 } 2505 2506 trace_qemu_loadvm_state_section(section_type); 2507 switch (section_type) { 2508 case QEMU_VM_SECTION_START: 2509 case QEMU_VM_SECTION_FULL: 2510 ret = qemu_loadvm_section_start_full(f, mis); 2511 if (ret < 0) { 2512 goto out; 2513 } 2514 break; 2515 case QEMU_VM_SECTION_PART: 2516 case QEMU_VM_SECTION_END: 2517 ret = qemu_loadvm_section_part_end(f, mis); 2518 if (ret < 0) { 2519 goto out; 2520 } 2521 break; 2522 case QEMU_VM_COMMAND: 2523 ret = loadvm_process_command(f); 2524 trace_qemu_loadvm_state_section_command(ret); 2525 if ((ret < 0) || (ret == LOADVM_QUIT)) { 2526 goto out; 2527 } 2528 break; 2529 case QEMU_VM_EOF: 2530 /* This is the end of migration */ 2531 goto out; 2532 default: 2533 error_report("Unknown savevm section type %d", section_type); 2534 ret = -EINVAL; 2535 goto out; 2536 } 2537 } 2538 2539 out: 2540 if (ret < 0) { 2541 qemu_file_set_error(f, ret); 2542 2543 /* Cancel bitmaps incoming regardless of recovery */ 2544 dirty_bitmap_mig_cancel_incoming(); 2545 2546 /* 2547 * If we are during an active postcopy, then we pause instead 2548 * of bail out to at least keep the VM's dirty data. Note 2549 * that POSTCOPY_INCOMING_LISTENING stage is still not enough, 2550 * during which we're still receiving device states and we 2551 * still haven't yet started the VM on destination. 2552 * 2553 * Only RAM postcopy supports recovery. Still, if RAM postcopy is 2554 * enabled, canceled bitmaps postcopy will not affect RAM postcopy 2555 * recovering. 2556 */ 2557 if (postcopy_state_get() == POSTCOPY_INCOMING_RUNNING && 2558 migrate_postcopy_ram() && postcopy_pause_incoming(mis)) { 2559 /* Reset f to point to the newly created channel */ 2560 f = mis->from_src_file; 2561 goto retry; 2562 } 2563 } 2564 return ret; 2565 } 2566 2567 int qemu_loadvm_state(QEMUFile *f) 2568 { 2569 MigrationIncomingState *mis = migration_incoming_get_current(); 2570 Error *local_err = NULL; 2571 int ret; 2572 2573 if (qemu_savevm_state_blocked(&local_err)) { 2574 error_report_err(local_err); 2575 return -EINVAL; 2576 } 2577 2578 ret = qemu_loadvm_state_header(f); 2579 if (ret) { 2580 return ret; 2581 } 2582 2583 if (qemu_loadvm_state_setup(f) != 0) { 2584 return -EINVAL; 2585 } 2586 2587 cpu_synchronize_all_pre_loadvm(); 2588 2589 ret = qemu_loadvm_state_main(f, mis); 2590 qemu_event_set(&mis->main_thread_load_event); 2591 2592 trace_qemu_loadvm_state_post_main(ret); 2593 2594 if (mis->have_listen_thread) { 2595 /* Listen thread still going, can't clean up yet */ 2596 return ret; 2597 } 2598 2599 if (ret == 0) { 2600 ret = qemu_file_get_error(f); 2601 } 2602 2603 /* 2604 * Try to read in the VMDESC section as well, so that dumping tools that 2605 * intercept our migration stream have the chance to see it. 2606 */ 2607 2608 /* We've got to be careful; if we don't read the data and just shut the fd 2609 * then the sender can error if we close while it's still sending. 2610 * We also mustn't read data that isn't there; some transports (RDMA) 2611 * will stall waiting for that data when the source has already closed. 2612 */ 2613 if (ret == 0 && should_send_vmdesc()) { 2614 uint8_t *buf; 2615 uint32_t size; 2616 uint8_t section_type = qemu_get_byte(f); 2617 2618 if (section_type != QEMU_VM_VMDESCRIPTION) { 2619 error_report("Expected vmdescription section, but got %d", 2620 section_type); 2621 /* 2622 * It doesn't seem worth failing at this point since 2623 * we apparently have an otherwise valid VM state 2624 */ 2625 } else { 2626 buf = g_malloc(0x1000); 2627 size = qemu_get_be32(f); 2628 2629 while (size > 0) { 2630 uint32_t read_chunk = MIN(size, 0x1000); 2631 qemu_get_buffer(f, buf, read_chunk); 2632 size -= read_chunk; 2633 } 2634 g_free(buf); 2635 } 2636 } 2637 2638 qemu_loadvm_state_cleanup(); 2639 cpu_synchronize_all_post_init(); 2640 2641 return ret; 2642 } 2643 2644 int qemu_load_device_state(QEMUFile *f) 2645 { 2646 MigrationIncomingState *mis = migration_incoming_get_current(); 2647 int ret; 2648 2649 /* Load QEMU_VM_SECTION_FULL section */ 2650 ret = qemu_loadvm_state_main(f, mis); 2651 if (ret < 0) { 2652 error_report("Failed to load device state: %d", ret); 2653 return ret; 2654 } 2655 2656 cpu_synchronize_all_post_init(); 2657 return 0; 2658 } 2659 2660 int save_snapshot(const char *name, Error **errp) 2661 { 2662 BlockDriverState *bs, *bs1; 2663 QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1; 2664 int ret = -1, ret2; 2665 QEMUFile *f; 2666 int saved_vm_running; 2667 uint64_t vm_state_size; 2668 qemu_timeval tv; 2669 struct tm tm; 2670 AioContext *aio_context; 2671 2672 if (migration_is_blocked(errp)) { 2673 return ret; 2674 } 2675 2676 if (!replay_can_snapshot()) { 2677 error_setg(errp, "Record/replay does not allow making snapshot " 2678 "right now. Try once more later."); 2679 return ret; 2680 } 2681 2682 if (!bdrv_all_can_snapshot(&bs)) { 2683 error_setg(errp, "Device '%s' is writable but does not support " 2684 "snapshots", bdrv_get_device_or_node_name(bs)); 2685 return ret; 2686 } 2687 2688 /* Delete old snapshots of the same name */ 2689 if (name) { 2690 ret = bdrv_all_delete_snapshot(name, &bs1, errp); 2691 if (ret < 0) { 2692 error_prepend(errp, "Error while deleting snapshot on device " 2693 "'%s': ", bdrv_get_device_or_node_name(bs1)); 2694 return ret; 2695 } 2696 } 2697 2698 bs = bdrv_all_find_vmstate_bs(); 2699 if (bs == NULL) { 2700 error_setg(errp, "No block device can accept snapshots"); 2701 return ret; 2702 } 2703 aio_context = bdrv_get_aio_context(bs); 2704 2705 saved_vm_running = runstate_is_running(); 2706 2707 ret = global_state_store(); 2708 if (ret) { 2709 error_setg(errp, "Error saving global state"); 2710 return ret; 2711 } 2712 vm_stop(RUN_STATE_SAVE_VM); 2713 2714 bdrv_drain_all_begin(); 2715 2716 aio_context_acquire(aio_context); 2717 2718 memset(sn, 0, sizeof(*sn)); 2719 2720 /* fill auxiliary fields */ 2721 qemu_gettimeofday(&tv); 2722 sn->date_sec = tv.tv_sec; 2723 sn->date_nsec = tv.tv_usec * 1000; 2724 sn->vm_clock_nsec = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 2725 if (replay_mode != REPLAY_MODE_NONE) { 2726 sn->icount = replay_get_current_icount(); 2727 } else { 2728 sn->icount = -1ULL; 2729 } 2730 2731 if (name) { 2732 ret = bdrv_snapshot_find(bs, old_sn, name); 2733 if (ret >= 0) { 2734 pstrcpy(sn->name, sizeof(sn->name), old_sn->name); 2735 pstrcpy(sn->id_str, sizeof(sn->id_str), old_sn->id_str); 2736 } else { 2737 pstrcpy(sn->name, sizeof(sn->name), name); 2738 } 2739 } else { 2740 /* cast below needed for OpenBSD where tv_sec is still 'long' */ 2741 localtime_r((const time_t *)&tv.tv_sec, &tm); 2742 strftime(sn->name, sizeof(sn->name), "vm-%Y%m%d%H%M%S", &tm); 2743 } 2744 2745 /* save the VM state */ 2746 f = qemu_fopen_bdrv(bs, 1); 2747 if (!f) { 2748 error_setg(errp, "Could not open VM state file"); 2749 goto the_end; 2750 } 2751 ret = qemu_savevm_state(f, errp); 2752 vm_state_size = qemu_ftell(f); 2753 ret2 = qemu_fclose(f); 2754 if (ret < 0) { 2755 goto the_end; 2756 } 2757 if (ret2 < 0) { 2758 ret = ret2; 2759 goto the_end; 2760 } 2761 2762 /* The bdrv_all_create_snapshot() call that follows acquires the AioContext 2763 * for itself. BDRV_POLL_WHILE() does not support nested locking because 2764 * it only releases the lock once. Therefore synchronous I/O will deadlock 2765 * unless we release the AioContext before bdrv_all_create_snapshot(). 2766 */ 2767 aio_context_release(aio_context); 2768 aio_context = NULL; 2769 2770 ret = bdrv_all_create_snapshot(sn, bs, vm_state_size, &bs); 2771 if (ret < 0) { 2772 error_setg(errp, "Error while creating snapshot on '%s'", 2773 bdrv_get_device_or_node_name(bs)); 2774 goto the_end; 2775 } 2776 2777 ret = 0; 2778 2779 the_end: 2780 if (aio_context) { 2781 aio_context_release(aio_context); 2782 } 2783 2784 bdrv_drain_all_end(); 2785 2786 if (saved_vm_running) { 2787 vm_start(); 2788 } 2789 return ret; 2790 } 2791 2792 void qmp_xen_save_devices_state(const char *filename, bool has_live, bool live, 2793 Error **errp) 2794 { 2795 QEMUFile *f; 2796 QIOChannelFile *ioc; 2797 int saved_vm_running; 2798 int ret; 2799 2800 if (!has_live) { 2801 /* live default to true so old version of Xen tool stack can have a 2802 * successful live migration */ 2803 live = true; 2804 } 2805 2806 saved_vm_running = runstate_is_running(); 2807 vm_stop(RUN_STATE_SAVE_VM); 2808 global_state_store_running(); 2809 2810 ioc = qio_channel_file_new_path(filename, O_WRONLY | O_CREAT | O_TRUNC, 2811 0660, errp); 2812 if (!ioc) { 2813 goto the_end; 2814 } 2815 qio_channel_set_name(QIO_CHANNEL(ioc), "migration-xen-save-state"); 2816 f = qemu_fopen_channel_output(QIO_CHANNEL(ioc)); 2817 object_unref(OBJECT(ioc)); 2818 ret = qemu_save_device_state(f); 2819 if (ret < 0 || qemu_fclose(f) < 0) { 2820 error_setg(errp, QERR_IO_ERROR); 2821 } else { 2822 /* libxl calls the QMP command "stop" before calling 2823 * "xen-save-devices-state" and in case of migration failure, libxl 2824 * would call "cont". 2825 * So call bdrv_inactivate_all (release locks) here to let the other 2826 * side of the migration take control of the images. 2827 */ 2828 if (live && !saved_vm_running) { 2829 ret = bdrv_inactivate_all(); 2830 if (ret) { 2831 error_setg(errp, "%s: bdrv_inactivate_all() failed (%d)", 2832 __func__, ret); 2833 } 2834 } 2835 } 2836 2837 the_end: 2838 if (saved_vm_running) { 2839 vm_start(); 2840 } 2841 } 2842 2843 void qmp_xen_load_devices_state(const char *filename, Error **errp) 2844 { 2845 QEMUFile *f; 2846 QIOChannelFile *ioc; 2847 int ret; 2848 2849 /* Guest must be paused before loading the device state; the RAM state 2850 * will already have been loaded by xc 2851 */ 2852 if (runstate_is_running()) { 2853 error_setg(errp, "Cannot update device state while vm is running"); 2854 return; 2855 } 2856 vm_stop(RUN_STATE_RESTORE_VM); 2857 2858 ioc = qio_channel_file_new_path(filename, O_RDONLY | O_BINARY, 0, errp); 2859 if (!ioc) { 2860 return; 2861 } 2862 qio_channel_set_name(QIO_CHANNEL(ioc), "migration-xen-load-state"); 2863 f = qemu_fopen_channel_input(QIO_CHANNEL(ioc)); 2864 object_unref(OBJECT(ioc)); 2865 2866 ret = qemu_loadvm_state(f); 2867 qemu_fclose(f); 2868 if (ret < 0) { 2869 error_setg(errp, QERR_IO_ERROR); 2870 } 2871 migration_incoming_state_destroy(); 2872 } 2873 2874 int load_snapshot(const char *name, Error **errp) 2875 { 2876 BlockDriverState *bs, *bs_vm_state; 2877 QEMUSnapshotInfo sn; 2878 QEMUFile *f; 2879 int ret; 2880 AioContext *aio_context; 2881 MigrationIncomingState *mis = migration_incoming_get_current(); 2882 2883 if (!bdrv_all_can_snapshot(&bs)) { 2884 error_setg(errp, 2885 "Device '%s' is writable but does not support snapshots", 2886 bdrv_get_device_or_node_name(bs)); 2887 return -ENOTSUP; 2888 } 2889 ret = bdrv_all_find_snapshot(name, &bs); 2890 if (ret < 0) { 2891 error_setg(errp, 2892 "Device '%s' does not have the requested snapshot '%s'", 2893 bdrv_get_device_or_node_name(bs), name); 2894 return ret; 2895 } 2896 2897 bs_vm_state = bdrv_all_find_vmstate_bs(); 2898 if (!bs_vm_state) { 2899 error_setg(errp, "No block device supports snapshots"); 2900 return -ENOTSUP; 2901 } 2902 aio_context = bdrv_get_aio_context(bs_vm_state); 2903 2904 /* Don't even try to load empty VM states */ 2905 aio_context_acquire(aio_context); 2906 ret = bdrv_snapshot_find(bs_vm_state, &sn, name); 2907 aio_context_release(aio_context); 2908 if (ret < 0) { 2909 return ret; 2910 } else if (sn.vm_state_size == 0) { 2911 error_setg(errp, "This is a disk-only snapshot. Revert to it " 2912 " offline using qemu-img"); 2913 return -EINVAL; 2914 } 2915 2916 /* 2917 * Flush the record/replay queue. Now the VM state is going 2918 * to change. Therefore we don't need to preserve its consistency 2919 */ 2920 replay_flush_events(); 2921 2922 /* Flush all IO requests so they don't interfere with the new state. */ 2923 bdrv_drain_all_begin(); 2924 2925 ret = bdrv_all_goto_snapshot(name, &bs, errp); 2926 if (ret < 0) { 2927 error_prepend(errp, "Could not load snapshot '%s' on '%s': ", 2928 name, bdrv_get_device_or_node_name(bs)); 2929 goto err_drain; 2930 } 2931 2932 /* restore the VM state */ 2933 f = qemu_fopen_bdrv(bs_vm_state, 0); 2934 if (!f) { 2935 error_setg(errp, "Could not open VM state file"); 2936 ret = -EINVAL; 2937 goto err_drain; 2938 } 2939 2940 qemu_system_reset(SHUTDOWN_CAUSE_NONE); 2941 mis->from_src_file = f; 2942 2943 aio_context_acquire(aio_context); 2944 ret = qemu_loadvm_state(f); 2945 migration_incoming_state_destroy(); 2946 aio_context_release(aio_context); 2947 2948 bdrv_drain_all_end(); 2949 2950 if (ret < 0) { 2951 error_setg(errp, "Error %d while loading VM state", ret); 2952 return ret; 2953 } 2954 2955 return 0; 2956 2957 err_drain: 2958 bdrv_drain_all_end(); 2959 return ret; 2960 } 2961 2962 void vmstate_register_ram(MemoryRegion *mr, DeviceState *dev) 2963 { 2964 qemu_ram_set_idstr(mr->ram_block, 2965 memory_region_name(mr), dev); 2966 qemu_ram_set_migratable(mr->ram_block); 2967 } 2968 2969 void vmstate_unregister_ram(MemoryRegion *mr, DeviceState *dev) 2970 { 2971 qemu_ram_unset_idstr(mr->ram_block); 2972 qemu_ram_unset_migratable(mr->ram_block); 2973 } 2974 2975 void vmstate_register_ram_global(MemoryRegion *mr) 2976 { 2977 vmstate_register_ram(mr, NULL); 2978 } 2979 2980 bool vmstate_check_only_migratable(const VMStateDescription *vmsd) 2981 { 2982 /* check needed if --only-migratable is specified */ 2983 if (!only_migratable) { 2984 return true; 2985 } 2986 2987 return !(vmsd && vmsd->unmigratable); 2988 } 2989