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 "migration/channel-block.h" 39 #include "ram.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/clone-visitor.h" 46 #include "qapi/qapi-builtin-visit.h" 47 #include "qapi/qmp/qerror.h" 48 #include "qemu/error-report.h" 49 #include "sysemu/cpus.h" 50 #include "exec/memory.h" 51 #include "exec/target_page.h" 52 #include "trace.h" 53 #include "qemu/iov.h" 54 #include "qemu/job.h" 55 #include "qemu/main-loop.h" 56 #include "block/snapshot.h" 57 #include "qemu/cutils.h" 58 #include "io/channel-buffer.h" 59 #include "io/channel-file.h" 60 #include "sysemu/replay.h" 61 #include "sysemu/runstate.h" 62 #include "sysemu/sysemu.h" 63 #include "sysemu/xen.h" 64 #include "migration/colo.h" 65 #include "qemu/bitmap.h" 66 #include "net/announce.h" 67 #include "qemu/yank.h" 68 #include "yank_functions.h" 69 70 const unsigned int postcopy_ram_discard_version; 71 72 /* Subcommands for QEMU_VM_COMMAND */ 73 enum qemu_vm_cmd { 74 MIG_CMD_INVALID = 0, /* Must be 0 */ 75 MIG_CMD_OPEN_RETURN_PATH, /* Tell the dest to open the Return path */ 76 MIG_CMD_PING, /* Request a PONG on the RP */ 77 78 MIG_CMD_POSTCOPY_ADVISE, /* Prior to any page transfers, just 79 warn we might want to do PC */ 80 MIG_CMD_POSTCOPY_LISTEN, /* Start listening for incoming 81 pages as it's running. */ 82 MIG_CMD_POSTCOPY_RUN, /* Start execution */ 83 84 MIG_CMD_POSTCOPY_RAM_DISCARD, /* A list of pages to discard that 85 were previously sent during 86 precopy but are dirty. */ 87 MIG_CMD_PACKAGED, /* Send a wrapped stream within this stream */ 88 MIG_CMD_ENABLE_COLO, /* Enable COLO */ 89 MIG_CMD_POSTCOPY_RESUME, /* resume postcopy on dest */ 90 MIG_CMD_RECV_BITMAP, /* Request for recved bitmap on dst */ 91 MIG_CMD_MAX 92 }; 93 94 #define MAX_VM_CMD_PACKAGED_SIZE UINT32_MAX 95 static struct mig_cmd_args { 96 ssize_t len; /* -1 = variable */ 97 const char *name; 98 } mig_cmd_args[] = { 99 [MIG_CMD_INVALID] = { .len = -1, .name = "INVALID" }, 100 [MIG_CMD_OPEN_RETURN_PATH] = { .len = 0, .name = "OPEN_RETURN_PATH" }, 101 [MIG_CMD_PING] = { .len = sizeof(uint32_t), .name = "PING" }, 102 [MIG_CMD_POSTCOPY_ADVISE] = { .len = -1, .name = "POSTCOPY_ADVISE" }, 103 [MIG_CMD_POSTCOPY_LISTEN] = { .len = 0, .name = "POSTCOPY_LISTEN" }, 104 [MIG_CMD_POSTCOPY_RUN] = { .len = 0, .name = "POSTCOPY_RUN" }, 105 [MIG_CMD_POSTCOPY_RAM_DISCARD] = { 106 .len = -1, .name = "POSTCOPY_RAM_DISCARD" }, 107 [MIG_CMD_POSTCOPY_RESUME] = { .len = 0, .name = "POSTCOPY_RESUME" }, 108 [MIG_CMD_PACKAGED] = { .len = 4, .name = "PACKAGED" }, 109 [MIG_CMD_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" }, 110 [MIG_CMD_MAX] = { .len = -1, .name = "MAX" }, 111 }; 112 113 /* Note for MIG_CMD_POSTCOPY_ADVISE: 114 * The format of arguments is depending on postcopy mode: 115 * - postcopy RAM only 116 * uint64_t host page size 117 * uint64_t taget page size 118 * 119 * - postcopy RAM and postcopy dirty bitmaps 120 * format is the same as for postcopy RAM only 121 * 122 * - postcopy dirty bitmaps only 123 * Nothing. Command length field is 0. 124 * 125 * Be careful: adding a new postcopy entity with some other parameters should 126 * not break format self-description ability. Good way is to introduce some 127 * generic extendable format with an exception for two old entities. 128 */ 129 130 /***********************************************************/ 131 /* savevm/loadvm support */ 132 133 static QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int is_writable) 134 { 135 if (is_writable) { 136 return qemu_file_new_output(QIO_CHANNEL(qio_channel_block_new(bs))); 137 } else { 138 return qemu_file_new_input(QIO_CHANNEL(qio_channel_block_new(bs))); 139 } 140 } 141 142 143 /* QEMUFile timer support. 144 * Not in qemu-file.c to not add qemu-timer.c as dependency to qemu-file.c 145 */ 146 147 void timer_put(QEMUFile *f, QEMUTimer *ts) 148 { 149 uint64_t expire_time; 150 151 expire_time = timer_expire_time_ns(ts); 152 qemu_put_be64(f, expire_time); 153 } 154 155 void timer_get(QEMUFile *f, QEMUTimer *ts) 156 { 157 uint64_t expire_time; 158 159 expire_time = qemu_get_be64(f); 160 if (expire_time != -1) { 161 timer_mod_ns(ts, expire_time); 162 } else { 163 timer_del(ts); 164 } 165 } 166 167 168 /* VMState timer support. 169 * Not in vmstate.c to not add qemu-timer.c as dependency to vmstate.c 170 */ 171 172 static int get_timer(QEMUFile *f, void *pv, size_t size, 173 const VMStateField *field) 174 { 175 QEMUTimer *v = pv; 176 timer_get(f, v); 177 return 0; 178 } 179 180 static int put_timer(QEMUFile *f, void *pv, size_t size, 181 const VMStateField *field, JSONWriter *vmdesc) 182 { 183 QEMUTimer *v = pv; 184 timer_put(f, v); 185 186 return 0; 187 } 188 189 const VMStateInfo vmstate_info_timer = { 190 .name = "timer", 191 .get = get_timer, 192 .put = put_timer, 193 }; 194 195 196 typedef struct CompatEntry { 197 char idstr[256]; 198 int instance_id; 199 } CompatEntry; 200 201 typedef struct SaveStateEntry { 202 QTAILQ_ENTRY(SaveStateEntry) entry; 203 char idstr[256]; 204 uint32_t instance_id; 205 int alias_id; 206 int version_id; 207 /* version id read from the stream */ 208 int load_version_id; 209 int section_id; 210 /* section id read from the stream */ 211 int load_section_id; 212 const SaveVMHandlers *ops; 213 const VMStateDescription *vmsd; 214 void *opaque; 215 CompatEntry *compat; 216 int is_ram; 217 } SaveStateEntry; 218 219 typedef struct SaveState { 220 QTAILQ_HEAD(, SaveStateEntry) handlers; 221 SaveStateEntry *handler_pri_head[MIG_PRI_MAX + 1]; 222 int global_section_id; 223 uint32_t len; 224 const char *name; 225 uint32_t target_page_bits; 226 uint32_t caps_count; 227 MigrationCapability *capabilities; 228 QemuUUID uuid; 229 } SaveState; 230 231 static SaveState savevm_state = { 232 .handlers = QTAILQ_HEAD_INITIALIZER(savevm_state.handlers), 233 .handler_pri_head = { [MIG_PRI_DEFAULT ... MIG_PRI_MAX] = NULL }, 234 .global_section_id = 0, 235 }; 236 237 static bool should_validate_capability(int capability) 238 { 239 assert(capability >= 0 && capability < MIGRATION_CAPABILITY__MAX); 240 /* Validate only new capabilities to keep compatibility. */ 241 switch (capability) { 242 case MIGRATION_CAPABILITY_X_IGNORE_SHARED: 243 return true; 244 default: 245 return false; 246 } 247 } 248 249 static uint32_t get_validatable_capabilities_count(void) 250 { 251 MigrationState *s = migrate_get_current(); 252 uint32_t result = 0; 253 int i; 254 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { 255 if (should_validate_capability(i) && s->enabled_capabilities[i]) { 256 result++; 257 } 258 } 259 return result; 260 } 261 262 static int configuration_pre_save(void *opaque) 263 { 264 SaveState *state = opaque; 265 const char *current_name = MACHINE_GET_CLASS(current_machine)->name; 266 MigrationState *s = migrate_get_current(); 267 int i, j; 268 269 state->len = strlen(current_name); 270 state->name = current_name; 271 state->target_page_bits = qemu_target_page_bits(); 272 273 state->caps_count = get_validatable_capabilities_count(); 274 state->capabilities = g_renew(MigrationCapability, state->capabilities, 275 state->caps_count); 276 for (i = j = 0; i < MIGRATION_CAPABILITY__MAX; i++) { 277 if (should_validate_capability(i) && s->enabled_capabilities[i]) { 278 state->capabilities[j++] = i; 279 } 280 } 281 state->uuid = qemu_uuid; 282 283 return 0; 284 } 285 286 static int configuration_post_save(void *opaque) 287 { 288 SaveState *state = opaque; 289 290 g_free(state->capabilities); 291 state->capabilities = NULL; 292 state->caps_count = 0; 293 return 0; 294 } 295 296 static int configuration_pre_load(void *opaque) 297 { 298 SaveState *state = opaque; 299 300 /* If there is no target-page-bits subsection it means the source 301 * predates the variable-target-page-bits support and is using the 302 * minimum possible value for this CPU. 303 */ 304 state->target_page_bits = qemu_target_page_bits_min(); 305 return 0; 306 } 307 308 static bool configuration_validate_capabilities(SaveState *state) 309 { 310 bool ret = true; 311 MigrationState *s = migrate_get_current(); 312 unsigned long *source_caps_bm; 313 int i; 314 315 source_caps_bm = bitmap_new(MIGRATION_CAPABILITY__MAX); 316 for (i = 0; i < state->caps_count; i++) { 317 MigrationCapability capability = state->capabilities[i]; 318 set_bit(capability, source_caps_bm); 319 } 320 321 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { 322 bool source_state, target_state; 323 if (!should_validate_capability(i)) { 324 continue; 325 } 326 source_state = test_bit(i, source_caps_bm); 327 target_state = s->enabled_capabilities[i]; 328 if (source_state != target_state) { 329 error_report("Capability %s is %s, but received capability is %s", 330 MigrationCapability_str(i), 331 target_state ? "on" : "off", 332 source_state ? "on" : "off"); 333 ret = false; 334 /* Don't break here to report all failed capabilities */ 335 } 336 } 337 338 g_free(source_caps_bm); 339 return ret; 340 } 341 342 static int configuration_post_load(void *opaque, int version_id) 343 { 344 SaveState *state = opaque; 345 const char *current_name = MACHINE_GET_CLASS(current_machine)->name; 346 int ret = 0; 347 348 if (strncmp(state->name, current_name, state->len) != 0) { 349 error_report("Machine type received is '%.*s' and local is '%s'", 350 (int) state->len, state->name, current_name); 351 ret = -EINVAL; 352 goto out; 353 } 354 355 if (state->target_page_bits != qemu_target_page_bits()) { 356 error_report("Received TARGET_PAGE_BITS is %d but local is %d", 357 state->target_page_bits, qemu_target_page_bits()); 358 ret = -EINVAL; 359 goto out; 360 } 361 362 if (!configuration_validate_capabilities(state)) { 363 ret = -EINVAL; 364 goto out; 365 } 366 367 out: 368 g_free((void *)state->name); 369 state->name = NULL; 370 state->len = 0; 371 g_free(state->capabilities); 372 state->capabilities = NULL; 373 state->caps_count = 0; 374 375 return ret; 376 } 377 378 static int get_capability(QEMUFile *f, void *pv, size_t size, 379 const VMStateField *field) 380 { 381 MigrationCapability *capability = pv; 382 char capability_str[UINT8_MAX + 1]; 383 uint8_t len; 384 int i; 385 386 len = qemu_get_byte(f); 387 qemu_get_buffer(f, (uint8_t *)capability_str, len); 388 capability_str[len] = '\0'; 389 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { 390 if (!strcmp(MigrationCapability_str(i), capability_str)) { 391 *capability = i; 392 return 0; 393 } 394 } 395 error_report("Received unknown capability %s", capability_str); 396 return -EINVAL; 397 } 398 399 static int put_capability(QEMUFile *f, void *pv, size_t size, 400 const VMStateField *field, JSONWriter *vmdesc) 401 { 402 MigrationCapability *capability = pv; 403 const char *capability_str = MigrationCapability_str(*capability); 404 size_t len = strlen(capability_str); 405 assert(len <= UINT8_MAX); 406 407 qemu_put_byte(f, len); 408 qemu_put_buffer(f, (uint8_t *)capability_str, len); 409 return 0; 410 } 411 412 static const VMStateInfo vmstate_info_capability = { 413 .name = "capability", 414 .get = get_capability, 415 .put = put_capability, 416 }; 417 418 /* The target-page-bits subsection is present only if the 419 * target page size is not the same as the default (ie the 420 * minimum page size for a variable-page-size guest CPU). 421 * If it is present then it contains the actual target page 422 * bits for the machine, and migration will fail if the 423 * two ends don't agree about it. 424 */ 425 static bool vmstate_target_page_bits_needed(void *opaque) 426 { 427 return qemu_target_page_bits() 428 > qemu_target_page_bits_min(); 429 } 430 431 static const VMStateDescription vmstate_target_page_bits = { 432 .name = "configuration/target-page-bits", 433 .version_id = 1, 434 .minimum_version_id = 1, 435 .needed = vmstate_target_page_bits_needed, 436 .fields = (VMStateField[]) { 437 VMSTATE_UINT32(target_page_bits, SaveState), 438 VMSTATE_END_OF_LIST() 439 } 440 }; 441 442 static bool vmstate_capabilites_needed(void *opaque) 443 { 444 return get_validatable_capabilities_count() > 0; 445 } 446 447 static const VMStateDescription vmstate_capabilites = { 448 .name = "configuration/capabilities", 449 .version_id = 1, 450 .minimum_version_id = 1, 451 .needed = vmstate_capabilites_needed, 452 .fields = (VMStateField[]) { 453 VMSTATE_UINT32_V(caps_count, SaveState, 1), 454 VMSTATE_VARRAY_UINT32_ALLOC(capabilities, SaveState, caps_count, 1, 455 vmstate_info_capability, 456 MigrationCapability), 457 VMSTATE_END_OF_LIST() 458 } 459 }; 460 461 static bool vmstate_uuid_needed(void *opaque) 462 { 463 return qemu_uuid_set && migrate_validate_uuid(); 464 } 465 466 static int vmstate_uuid_post_load(void *opaque, int version_id) 467 { 468 SaveState *state = opaque; 469 char uuid_src[UUID_FMT_LEN + 1]; 470 char uuid_dst[UUID_FMT_LEN + 1]; 471 472 if (!qemu_uuid_set) { 473 /* 474 * It's warning because user might not know UUID in some cases, 475 * e.g. load an old snapshot 476 */ 477 qemu_uuid_unparse(&state->uuid, uuid_src); 478 warn_report("UUID is received %s, but local uuid isn't set", 479 uuid_src); 480 return 0; 481 } 482 if (!qemu_uuid_is_equal(&state->uuid, &qemu_uuid)) { 483 qemu_uuid_unparse(&state->uuid, uuid_src); 484 qemu_uuid_unparse(&qemu_uuid, uuid_dst); 485 error_report("UUID received is %s and local is %s", uuid_src, uuid_dst); 486 return -EINVAL; 487 } 488 return 0; 489 } 490 491 static const VMStateDescription vmstate_uuid = { 492 .name = "configuration/uuid", 493 .version_id = 1, 494 .minimum_version_id = 1, 495 .needed = vmstate_uuid_needed, 496 .post_load = vmstate_uuid_post_load, 497 .fields = (VMStateField[]) { 498 VMSTATE_UINT8_ARRAY_V(uuid.data, SaveState, sizeof(QemuUUID), 1), 499 VMSTATE_END_OF_LIST() 500 } 501 }; 502 503 static const VMStateDescription vmstate_configuration = { 504 .name = "configuration", 505 .version_id = 1, 506 .pre_load = configuration_pre_load, 507 .post_load = configuration_post_load, 508 .pre_save = configuration_pre_save, 509 .post_save = configuration_post_save, 510 .fields = (VMStateField[]) { 511 VMSTATE_UINT32(len, SaveState), 512 VMSTATE_VBUFFER_ALLOC_UINT32(name, SaveState, 0, NULL, len), 513 VMSTATE_END_OF_LIST() 514 }, 515 .subsections = (const VMStateDescription *[]) { 516 &vmstate_target_page_bits, 517 &vmstate_capabilites, 518 &vmstate_uuid, 519 NULL 520 } 521 }; 522 523 static void dump_vmstate_vmsd(FILE *out_file, 524 const VMStateDescription *vmsd, int indent, 525 bool is_subsection); 526 527 static void dump_vmstate_vmsf(FILE *out_file, const VMStateField *field, 528 int indent) 529 { 530 fprintf(out_file, "%*s{\n", indent, ""); 531 indent += 2; 532 fprintf(out_file, "%*s\"field\": \"%s\",\n", indent, "", field->name); 533 fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "", 534 field->version_id); 535 fprintf(out_file, "%*s\"field_exists\": %s,\n", indent, "", 536 field->field_exists ? "true" : "false"); 537 fprintf(out_file, "%*s\"size\": %zu", indent, "", field->size); 538 if (field->vmsd != NULL) { 539 fprintf(out_file, ",\n"); 540 dump_vmstate_vmsd(out_file, field->vmsd, indent, false); 541 } 542 fprintf(out_file, "\n%*s}", indent - 2, ""); 543 } 544 545 static void dump_vmstate_vmss(FILE *out_file, 546 const VMStateDescription **subsection, 547 int indent) 548 { 549 if (*subsection != NULL) { 550 dump_vmstate_vmsd(out_file, *subsection, indent, true); 551 } 552 } 553 554 static void dump_vmstate_vmsd(FILE *out_file, 555 const VMStateDescription *vmsd, int indent, 556 bool is_subsection) 557 { 558 if (is_subsection) { 559 fprintf(out_file, "%*s{\n", indent, ""); 560 } else { 561 fprintf(out_file, "%*s\"%s\": {\n", indent, "", "Description"); 562 } 563 indent += 2; 564 fprintf(out_file, "%*s\"name\": \"%s\",\n", indent, "", vmsd->name); 565 fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "", 566 vmsd->version_id); 567 fprintf(out_file, "%*s\"minimum_version_id\": %d", indent, "", 568 vmsd->minimum_version_id); 569 if (vmsd->fields != NULL) { 570 const VMStateField *field = vmsd->fields; 571 bool first; 572 573 fprintf(out_file, ",\n%*s\"Fields\": [\n", indent, ""); 574 first = true; 575 while (field->name != NULL) { 576 if (field->flags & VMS_MUST_EXIST) { 577 /* Ignore VMSTATE_VALIDATE bits; these don't get migrated */ 578 field++; 579 continue; 580 } 581 if (!first) { 582 fprintf(out_file, ",\n"); 583 } 584 dump_vmstate_vmsf(out_file, field, indent + 2); 585 field++; 586 first = false; 587 } 588 fprintf(out_file, "\n%*s]", indent, ""); 589 } 590 if (vmsd->subsections != NULL) { 591 const VMStateDescription **subsection = vmsd->subsections; 592 bool first; 593 594 fprintf(out_file, ",\n%*s\"Subsections\": [\n", indent, ""); 595 first = true; 596 while (*subsection != NULL) { 597 if (!first) { 598 fprintf(out_file, ",\n"); 599 } 600 dump_vmstate_vmss(out_file, subsection, indent + 2); 601 subsection++; 602 first = false; 603 } 604 fprintf(out_file, "\n%*s]", indent, ""); 605 } 606 fprintf(out_file, "\n%*s}", indent - 2, ""); 607 } 608 609 static void dump_machine_type(FILE *out_file) 610 { 611 MachineClass *mc; 612 613 mc = MACHINE_GET_CLASS(current_machine); 614 615 fprintf(out_file, " \"vmschkmachine\": {\n"); 616 fprintf(out_file, " \"Name\": \"%s\"\n", mc->name); 617 fprintf(out_file, " },\n"); 618 } 619 620 void dump_vmstate_json_to_file(FILE *out_file) 621 { 622 GSList *list, *elt; 623 bool first; 624 625 fprintf(out_file, "{\n"); 626 dump_machine_type(out_file); 627 628 first = true; 629 list = object_class_get_list(TYPE_DEVICE, true); 630 for (elt = list; elt; elt = elt->next) { 631 DeviceClass *dc = OBJECT_CLASS_CHECK(DeviceClass, elt->data, 632 TYPE_DEVICE); 633 const char *name; 634 int indent = 2; 635 636 if (!dc->vmsd) { 637 continue; 638 } 639 640 if (!first) { 641 fprintf(out_file, ",\n"); 642 } 643 name = object_class_get_name(OBJECT_CLASS(dc)); 644 fprintf(out_file, "%*s\"%s\": {\n", indent, "", name); 645 indent += 2; 646 fprintf(out_file, "%*s\"Name\": \"%s\",\n", indent, "", name); 647 fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "", 648 dc->vmsd->version_id); 649 fprintf(out_file, "%*s\"minimum_version_id\": %d,\n", indent, "", 650 dc->vmsd->minimum_version_id); 651 652 dump_vmstate_vmsd(out_file, dc->vmsd, indent, false); 653 654 fprintf(out_file, "\n%*s}", indent - 2, ""); 655 first = false; 656 } 657 fprintf(out_file, "\n}\n"); 658 fclose(out_file); 659 g_slist_free(list); 660 } 661 662 static uint32_t calculate_new_instance_id(const char *idstr) 663 { 664 SaveStateEntry *se; 665 uint32_t instance_id = 0; 666 667 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 668 if (strcmp(idstr, se->idstr) == 0 669 && instance_id <= se->instance_id) { 670 instance_id = se->instance_id + 1; 671 } 672 } 673 /* Make sure we never loop over without being noticed */ 674 assert(instance_id != VMSTATE_INSTANCE_ID_ANY); 675 return instance_id; 676 } 677 678 static int calculate_compat_instance_id(const char *idstr) 679 { 680 SaveStateEntry *se; 681 int instance_id = 0; 682 683 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 684 if (!se->compat) { 685 continue; 686 } 687 688 if (strcmp(idstr, se->compat->idstr) == 0 689 && instance_id <= se->compat->instance_id) { 690 instance_id = se->compat->instance_id + 1; 691 } 692 } 693 return instance_id; 694 } 695 696 static inline MigrationPriority save_state_priority(SaveStateEntry *se) 697 { 698 if (se->vmsd) { 699 return se->vmsd->priority; 700 } 701 return MIG_PRI_DEFAULT; 702 } 703 704 static void savevm_state_handler_insert(SaveStateEntry *nse) 705 { 706 MigrationPriority priority = save_state_priority(nse); 707 SaveStateEntry *se; 708 int i; 709 710 assert(priority <= MIG_PRI_MAX); 711 712 for (i = priority - 1; i >= 0; i--) { 713 se = savevm_state.handler_pri_head[i]; 714 if (se != NULL) { 715 assert(save_state_priority(se) < priority); 716 break; 717 } 718 } 719 720 if (i >= 0) { 721 QTAILQ_INSERT_BEFORE(se, nse, entry); 722 } else { 723 QTAILQ_INSERT_TAIL(&savevm_state.handlers, nse, entry); 724 } 725 726 if (savevm_state.handler_pri_head[priority] == NULL) { 727 savevm_state.handler_pri_head[priority] = nse; 728 } 729 } 730 731 static void savevm_state_handler_remove(SaveStateEntry *se) 732 { 733 SaveStateEntry *next; 734 MigrationPriority priority = save_state_priority(se); 735 736 if (se == savevm_state.handler_pri_head[priority]) { 737 next = QTAILQ_NEXT(se, entry); 738 if (next != NULL && save_state_priority(next) == priority) { 739 savevm_state.handler_pri_head[priority] = next; 740 } else { 741 savevm_state.handler_pri_head[priority] = NULL; 742 } 743 } 744 QTAILQ_REMOVE(&savevm_state.handlers, se, entry); 745 } 746 747 /* TODO: Individual devices generally have very little idea about the rest 748 of the system, so instance_id should be removed/replaced. 749 Meanwhile pass -1 as instance_id if you do not already have a clearly 750 distinguishing id for all instances of your device class. */ 751 int register_savevm_live(const char *idstr, 752 uint32_t instance_id, 753 int version_id, 754 const SaveVMHandlers *ops, 755 void *opaque) 756 { 757 SaveStateEntry *se; 758 759 se = g_new0(SaveStateEntry, 1); 760 se->version_id = version_id; 761 se->section_id = savevm_state.global_section_id++; 762 se->ops = ops; 763 se->opaque = opaque; 764 se->vmsd = NULL; 765 /* if this is a live_savem then set is_ram */ 766 if (ops->save_setup != NULL) { 767 se->is_ram = 1; 768 } 769 770 pstrcat(se->idstr, sizeof(se->idstr), idstr); 771 772 if (instance_id == VMSTATE_INSTANCE_ID_ANY) { 773 se->instance_id = calculate_new_instance_id(se->idstr); 774 } else { 775 se->instance_id = instance_id; 776 } 777 assert(!se->compat || se->instance_id == 0); 778 savevm_state_handler_insert(se); 779 return 0; 780 } 781 782 void unregister_savevm(VMStateIf *obj, const char *idstr, void *opaque) 783 { 784 SaveStateEntry *se, *new_se; 785 char id[256] = ""; 786 787 if (obj) { 788 char *oid = vmstate_if_get_id(obj); 789 if (oid) { 790 pstrcpy(id, sizeof(id), oid); 791 pstrcat(id, sizeof(id), "/"); 792 g_free(oid); 793 } 794 } 795 pstrcat(id, sizeof(id), idstr); 796 797 QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) { 798 if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) { 799 savevm_state_handler_remove(se); 800 g_free(se->compat); 801 g_free(se); 802 } 803 } 804 } 805 806 int vmstate_register_with_alias_id(VMStateIf *obj, uint32_t instance_id, 807 const VMStateDescription *vmsd, 808 void *opaque, int alias_id, 809 int required_for_version, 810 Error **errp) 811 { 812 SaveStateEntry *se; 813 814 /* If this triggers, alias support can be dropped for the vmsd. */ 815 assert(alias_id == -1 || required_for_version >= vmsd->minimum_version_id); 816 817 se = g_new0(SaveStateEntry, 1); 818 se->version_id = vmsd->version_id; 819 se->section_id = savevm_state.global_section_id++; 820 se->opaque = opaque; 821 se->vmsd = vmsd; 822 se->alias_id = alias_id; 823 824 if (obj) { 825 char *id = vmstate_if_get_id(obj); 826 if (id) { 827 if (snprintf(se->idstr, sizeof(se->idstr), "%s/", id) >= 828 sizeof(se->idstr)) { 829 error_setg(errp, "Path too long for VMState (%s)", id); 830 g_free(id); 831 g_free(se); 832 833 return -1; 834 } 835 g_free(id); 836 837 se->compat = g_new0(CompatEntry, 1); 838 pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), vmsd->name); 839 se->compat->instance_id = instance_id == VMSTATE_INSTANCE_ID_ANY ? 840 calculate_compat_instance_id(vmsd->name) : instance_id; 841 instance_id = VMSTATE_INSTANCE_ID_ANY; 842 } 843 } 844 pstrcat(se->idstr, sizeof(se->idstr), vmsd->name); 845 846 if (instance_id == VMSTATE_INSTANCE_ID_ANY) { 847 se->instance_id = calculate_new_instance_id(se->idstr); 848 } else { 849 se->instance_id = instance_id; 850 } 851 assert(!se->compat || se->instance_id == 0); 852 savevm_state_handler_insert(se); 853 return 0; 854 } 855 856 void vmstate_unregister(VMStateIf *obj, const VMStateDescription *vmsd, 857 void *opaque) 858 { 859 SaveStateEntry *se, *new_se; 860 861 QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) { 862 if (se->vmsd == vmsd && se->opaque == opaque) { 863 savevm_state_handler_remove(se); 864 g_free(se->compat); 865 g_free(se); 866 } 867 } 868 } 869 870 static int vmstate_load(QEMUFile *f, SaveStateEntry *se) 871 { 872 trace_vmstate_load(se->idstr, se->vmsd ? se->vmsd->name : "(old)"); 873 if (!se->vmsd) { /* Old style */ 874 return se->ops->load_state(f, se->opaque, se->load_version_id); 875 } 876 return vmstate_load_state(f, se->vmsd, se->opaque, se->load_version_id); 877 } 878 879 static void vmstate_save_old_style(QEMUFile *f, SaveStateEntry *se, 880 JSONWriter *vmdesc) 881 { 882 int64_t old_offset, size; 883 884 old_offset = qemu_file_total_transferred_fast(f); 885 se->ops->save_state(f, se->opaque); 886 size = qemu_file_total_transferred_fast(f) - old_offset; 887 888 if (vmdesc) { 889 json_writer_int64(vmdesc, "size", size); 890 json_writer_start_array(vmdesc, "fields"); 891 json_writer_start_object(vmdesc, NULL); 892 json_writer_str(vmdesc, "name", "data"); 893 json_writer_int64(vmdesc, "size", size); 894 json_writer_str(vmdesc, "type", "buffer"); 895 json_writer_end_object(vmdesc); 896 json_writer_end_array(vmdesc); 897 } 898 } 899 900 /* 901 * Write the header for device section (QEMU_VM_SECTION START/END/PART/FULL) 902 */ 903 static void save_section_header(QEMUFile *f, SaveStateEntry *se, 904 uint8_t section_type) 905 { 906 qemu_put_byte(f, section_type); 907 qemu_put_be32(f, se->section_id); 908 909 if (section_type == QEMU_VM_SECTION_FULL || 910 section_type == QEMU_VM_SECTION_START) { 911 /* ID string */ 912 size_t len = strlen(se->idstr); 913 qemu_put_byte(f, len); 914 qemu_put_buffer(f, (uint8_t *)se->idstr, len); 915 916 qemu_put_be32(f, se->instance_id); 917 qemu_put_be32(f, se->version_id); 918 } 919 } 920 921 /* 922 * Write a footer onto device sections that catches cases misformatted device 923 * sections. 924 */ 925 static void save_section_footer(QEMUFile *f, SaveStateEntry *se) 926 { 927 if (migrate_get_current()->send_section_footer) { 928 qemu_put_byte(f, QEMU_VM_SECTION_FOOTER); 929 qemu_put_be32(f, se->section_id); 930 } 931 } 932 933 static int vmstate_save(QEMUFile *f, SaveStateEntry *se, JSONWriter *vmdesc) 934 { 935 int ret; 936 937 if ((!se->ops || !se->ops->save_state) && !se->vmsd) { 938 return 0; 939 } 940 if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) { 941 trace_savevm_section_skip(se->idstr, se->section_id); 942 return 0; 943 } 944 945 trace_savevm_section_start(se->idstr, se->section_id); 946 save_section_header(f, se, QEMU_VM_SECTION_FULL); 947 if (vmdesc) { 948 json_writer_start_object(vmdesc, NULL); 949 json_writer_str(vmdesc, "name", se->idstr); 950 json_writer_int64(vmdesc, "instance_id", se->instance_id); 951 } 952 953 trace_vmstate_save(se->idstr, se->vmsd ? se->vmsd->name : "(old)"); 954 if (!se->vmsd) { 955 vmstate_save_old_style(f, se, vmdesc); 956 } else { 957 ret = vmstate_save_state(f, se->vmsd, se->opaque, vmdesc); 958 if (ret) { 959 return ret; 960 } 961 } 962 963 trace_savevm_section_end(se->idstr, se->section_id, 0); 964 save_section_footer(f, se); 965 if (vmdesc) { 966 json_writer_end_object(vmdesc); 967 } 968 return 0; 969 } 970 /** 971 * qemu_savevm_command_send: Send a 'QEMU_VM_COMMAND' type element with the 972 * command and associated data. 973 * 974 * @f: File to send command on 975 * @command: Command type to send 976 * @len: Length of associated data 977 * @data: Data associated with command. 978 */ 979 static void qemu_savevm_command_send(QEMUFile *f, 980 enum qemu_vm_cmd command, 981 uint16_t len, 982 uint8_t *data) 983 { 984 trace_savevm_command_send(command, len); 985 qemu_put_byte(f, QEMU_VM_COMMAND); 986 qemu_put_be16(f, (uint16_t)command); 987 qemu_put_be16(f, len); 988 qemu_put_buffer(f, data, len); 989 qemu_fflush(f); 990 } 991 992 void qemu_savevm_send_colo_enable(QEMUFile *f) 993 { 994 trace_savevm_send_colo_enable(); 995 qemu_savevm_command_send(f, MIG_CMD_ENABLE_COLO, 0, NULL); 996 } 997 998 void qemu_savevm_send_ping(QEMUFile *f, uint32_t value) 999 { 1000 uint32_t buf; 1001 1002 trace_savevm_send_ping(value); 1003 buf = cpu_to_be32(value); 1004 qemu_savevm_command_send(f, MIG_CMD_PING, sizeof(value), (uint8_t *)&buf); 1005 } 1006 1007 void qemu_savevm_send_open_return_path(QEMUFile *f) 1008 { 1009 trace_savevm_send_open_return_path(); 1010 qemu_savevm_command_send(f, MIG_CMD_OPEN_RETURN_PATH, 0, NULL); 1011 } 1012 1013 /* We have a buffer of data to send; we don't want that all to be loaded 1014 * by the command itself, so the command contains just the length of the 1015 * extra buffer that we then send straight after it. 1016 * TODO: Must be a better way to organise that 1017 * 1018 * Returns: 1019 * 0 on success 1020 * -ve on error 1021 */ 1022 int qemu_savevm_send_packaged(QEMUFile *f, const uint8_t *buf, size_t len) 1023 { 1024 uint32_t tmp; 1025 1026 if (len > MAX_VM_CMD_PACKAGED_SIZE) { 1027 error_report("%s: Unreasonably large packaged state: %zu", 1028 __func__, len); 1029 return -1; 1030 } 1031 1032 tmp = cpu_to_be32(len); 1033 1034 trace_qemu_savevm_send_packaged(); 1035 qemu_savevm_command_send(f, MIG_CMD_PACKAGED, 4, (uint8_t *)&tmp); 1036 1037 qemu_put_buffer(f, buf, len); 1038 1039 return 0; 1040 } 1041 1042 /* Send prior to any postcopy transfer */ 1043 void qemu_savevm_send_postcopy_advise(QEMUFile *f) 1044 { 1045 if (migrate_postcopy_ram()) { 1046 uint64_t tmp[2]; 1047 tmp[0] = cpu_to_be64(ram_pagesize_summary()); 1048 tmp[1] = cpu_to_be64(qemu_target_page_size()); 1049 1050 trace_qemu_savevm_send_postcopy_advise(); 1051 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_ADVISE, 1052 16, (uint8_t *)tmp); 1053 } else { 1054 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_ADVISE, 0, NULL); 1055 } 1056 } 1057 1058 /* Sent prior to starting the destination running in postcopy, discard pages 1059 * that have already been sent but redirtied on the source. 1060 * CMD_POSTCOPY_RAM_DISCARD consist of: 1061 * byte version (0) 1062 * byte Length of name field (not including 0) 1063 * n x byte RAM block name 1064 * byte 0 terminator (just for safety) 1065 * n x Byte ranges within the named RAMBlock 1066 * be64 Start of the range 1067 * be64 Length 1068 * 1069 * name: RAMBlock name that these entries are part of 1070 * len: Number of page entries 1071 * start_list: 'len' addresses 1072 * length_list: 'len' addresses 1073 * 1074 */ 1075 void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name, 1076 uint16_t len, 1077 uint64_t *start_list, 1078 uint64_t *length_list) 1079 { 1080 uint8_t *buf; 1081 uint16_t tmplen; 1082 uint16_t t; 1083 size_t name_len = strlen(name); 1084 1085 trace_qemu_savevm_send_postcopy_ram_discard(name, len); 1086 assert(name_len < 256); 1087 buf = g_malloc0(1 + 1 + name_len + 1 + (8 + 8) * len); 1088 buf[0] = postcopy_ram_discard_version; 1089 buf[1] = name_len; 1090 memcpy(buf + 2, name, name_len); 1091 tmplen = 2 + name_len; 1092 buf[tmplen++] = '\0'; 1093 1094 for (t = 0; t < len; t++) { 1095 stq_be_p(buf + tmplen, start_list[t]); 1096 tmplen += 8; 1097 stq_be_p(buf + tmplen, length_list[t]); 1098 tmplen += 8; 1099 } 1100 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RAM_DISCARD, tmplen, buf); 1101 g_free(buf); 1102 } 1103 1104 /* Get the destination into a state where it can receive postcopy data. */ 1105 void qemu_savevm_send_postcopy_listen(QEMUFile *f) 1106 { 1107 trace_savevm_send_postcopy_listen(); 1108 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_LISTEN, 0, NULL); 1109 } 1110 1111 /* Kick the destination into running */ 1112 void qemu_savevm_send_postcopy_run(QEMUFile *f) 1113 { 1114 trace_savevm_send_postcopy_run(); 1115 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RUN, 0, NULL); 1116 } 1117 1118 void qemu_savevm_send_postcopy_resume(QEMUFile *f) 1119 { 1120 trace_savevm_send_postcopy_resume(); 1121 qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RESUME, 0, NULL); 1122 } 1123 1124 void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name) 1125 { 1126 size_t len; 1127 char buf[256]; 1128 1129 trace_savevm_send_recv_bitmap(block_name); 1130 1131 buf[0] = len = strlen(block_name); 1132 memcpy(buf + 1, block_name, len); 1133 1134 qemu_savevm_command_send(f, MIG_CMD_RECV_BITMAP, len + 1, (uint8_t *)buf); 1135 } 1136 1137 bool qemu_savevm_state_blocked(Error **errp) 1138 { 1139 SaveStateEntry *se; 1140 1141 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1142 if (se->vmsd && se->vmsd->unmigratable) { 1143 error_setg(errp, "State blocked by non-migratable device '%s'", 1144 se->idstr); 1145 return true; 1146 } 1147 } 1148 return false; 1149 } 1150 1151 void qemu_savevm_non_migratable_list(strList **reasons) 1152 { 1153 SaveStateEntry *se; 1154 1155 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1156 if (se->vmsd && se->vmsd->unmigratable) { 1157 QAPI_LIST_PREPEND(*reasons, 1158 g_strdup_printf("non-migratable device: %s", 1159 se->idstr)); 1160 } 1161 } 1162 } 1163 1164 void qemu_savevm_state_header(QEMUFile *f) 1165 { 1166 trace_savevm_state_header(); 1167 qemu_put_be32(f, QEMU_VM_FILE_MAGIC); 1168 qemu_put_be32(f, QEMU_VM_FILE_VERSION); 1169 1170 if (migrate_get_current()->send_configuration) { 1171 qemu_put_byte(f, QEMU_VM_CONFIGURATION); 1172 vmstate_save_state(f, &vmstate_configuration, &savevm_state, 0); 1173 } 1174 } 1175 1176 bool qemu_savevm_state_guest_unplug_pending(void) 1177 { 1178 SaveStateEntry *se; 1179 1180 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1181 if (se->vmsd && se->vmsd->dev_unplug_pending && 1182 se->vmsd->dev_unplug_pending(se->opaque)) { 1183 return true; 1184 } 1185 } 1186 1187 return false; 1188 } 1189 1190 void qemu_savevm_state_setup(QEMUFile *f) 1191 { 1192 MigrationState *ms = migrate_get_current(); 1193 SaveStateEntry *se; 1194 Error *local_err = NULL; 1195 int ret; 1196 1197 ms->vmdesc = json_writer_new(false); 1198 json_writer_start_object(ms->vmdesc, NULL); 1199 json_writer_int64(ms->vmdesc, "page_size", qemu_target_page_size()); 1200 json_writer_start_array(ms->vmdesc, "devices"); 1201 1202 trace_savevm_state_setup(); 1203 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1204 if (se->vmsd && se->vmsd->early_setup) { 1205 ret = vmstate_save(f, se, ms->vmdesc); 1206 if (ret) { 1207 qemu_file_set_error(f, ret); 1208 break; 1209 } 1210 continue; 1211 } 1212 1213 if (!se->ops || !se->ops->save_setup) { 1214 continue; 1215 } 1216 if (se->ops->is_active) { 1217 if (!se->ops->is_active(se->opaque)) { 1218 continue; 1219 } 1220 } 1221 save_section_header(f, se, QEMU_VM_SECTION_START); 1222 1223 ret = se->ops->save_setup(f, se->opaque); 1224 save_section_footer(f, se); 1225 if (ret < 0) { 1226 qemu_file_set_error(f, ret); 1227 break; 1228 } 1229 } 1230 1231 if (precopy_notify(PRECOPY_NOTIFY_SETUP, &local_err)) { 1232 error_report_err(local_err); 1233 } 1234 } 1235 1236 int qemu_savevm_state_resume_prepare(MigrationState *s) 1237 { 1238 SaveStateEntry *se; 1239 int ret; 1240 1241 trace_savevm_state_resume_prepare(); 1242 1243 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1244 if (!se->ops || !se->ops->resume_prepare) { 1245 continue; 1246 } 1247 if (se->ops->is_active) { 1248 if (!se->ops->is_active(se->opaque)) { 1249 continue; 1250 } 1251 } 1252 ret = se->ops->resume_prepare(s, se->opaque); 1253 if (ret < 0) { 1254 return ret; 1255 } 1256 } 1257 1258 return 0; 1259 } 1260 1261 /* 1262 * this function has three return values: 1263 * negative: there was one error, and we have -errno. 1264 * 0 : We haven't finished, caller have to go again 1265 * 1 : We have finished, we can go to complete phase 1266 */ 1267 int qemu_savevm_state_iterate(QEMUFile *f, bool postcopy) 1268 { 1269 SaveStateEntry *se; 1270 int ret = 1; 1271 1272 trace_savevm_state_iterate(); 1273 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1274 if (!se->ops || !se->ops->save_live_iterate) { 1275 continue; 1276 } 1277 if (se->ops->is_active && 1278 !se->ops->is_active(se->opaque)) { 1279 continue; 1280 } 1281 if (se->ops->is_active_iterate && 1282 !se->ops->is_active_iterate(se->opaque)) { 1283 continue; 1284 } 1285 /* 1286 * In the postcopy phase, any device that doesn't know how to 1287 * do postcopy should have saved it's state in the _complete 1288 * call that's already run, it might get confused if we call 1289 * iterate afterwards. 1290 */ 1291 if (postcopy && 1292 !(se->ops->has_postcopy && se->ops->has_postcopy(se->opaque))) { 1293 continue; 1294 } 1295 if (qemu_file_rate_limit(f)) { 1296 return 0; 1297 } 1298 trace_savevm_section_start(se->idstr, se->section_id); 1299 1300 save_section_header(f, se, QEMU_VM_SECTION_PART); 1301 1302 ret = se->ops->save_live_iterate(f, se->opaque); 1303 trace_savevm_section_end(se->idstr, se->section_id, ret); 1304 save_section_footer(f, se); 1305 1306 if (ret < 0) { 1307 error_report("failed to save SaveStateEntry with id(name): " 1308 "%d(%s): %d", 1309 se->section_id, se->idstr, ret); 1310 qemu_file_set_error(f, ret); 1311 } 1312 if (ret <= 0) { 1313 /* Do not proceed to the next vmstate before this one reported 1314 completion of the current stage. This serializes the migration 1315 and reduces the probability that a faster changing state is 1316 synchronized over and over again. */ 1317 break; 1318 } 1319 } 1320 return ret; 1321 } 1322 1323 static bool should_send_vmdesc(void) 1324 { 1325 MachineState *machine = MACHINE(qdev_get_machine()); 1326 bool in_postcopy = migration_in_postcopy(); 1327 return !machine->suppress_vmdesc && !in_postcopy; 1328 } 1329 1330 /* 1331 * Calls the save_live_complete_postcopy methods 1332 * causing the last few pages to be sent immediately and doing any associated 1333 * cleanup. 1334 * Note postcopy also calls qemu_savevm_state_complete_precopy to complete 1335 * all the other devices, but that happens at the point we switch to postcopy. 1336 */ 1337 void qemu_savevm_state_complete_postcopy(QEMUFile *f) 1338 { 1339 SaveStateEntry *se; 1340 int ret; 1341 1342 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1343 if (!se->ops || !se->ops->save_live_complete_postcopy) { 1344 continue; 1345 } 1346 if (se->ops->is_active) { 1347 if (!se->ops->is_active(se->opaque)) { 1348 continue; 1349 } 1350 } 1351 trace_savevm_section_start(se->idstr, se->section_id); 1352 /* Section type */ 1353 qemu_put_byte(f, QEMU_VM_SECTION_END); 1354 qemu_put_be32(f, se->section_id); 1355 1356 ret = se->ops->save_live_complete_postcopy(f, se->opaque); 1357 trace_savevm_section_end(se->idstr, se->section_id, ret); 1358 save_section_footer(f, se); 1359 if (ret < 0) { 1360 qemu_file_set_error(f, ret); 1361 return; 1362 } 1363 } 1364 1365 qemu_put_byte(f, QEMU_VM_EOF); 1366 qemu_fflush(f); 1367 } 1368 1369 static 1370 int qemu_savevm_state_complete_precopy_iterable(QEMUFile *f, bool in_postcopy) 1371 { 1372 SaveStateEntry *se; 1373 int ret; 1374 1375 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1376 if (!se->ops || 1377 (in_postcopy && se->ops->has_postcopy && 1378 se->ops->has_postcopy(se->opaque)) || 1379 !se->ops->save_live_complete_precopy) { 1380 continue; 1381 } 1382 1383 if (se->ops->is_active) { 1384 if (!se->ops->is_active(se->opaque)) { 1385 continue; 1386 } 1387 } 1388 trace_savevm_section_start(se->idstr, se->section_id); 1389 1390 save_section_header(f, se, QEMU_VM_SECTION_END); 1391 1392 ret = se->ops->save_live_complete_precopy(f, se->opaque); 1393 trace_savevm_section_end(se->idstr, se->section_id, ret); 1394 save_section_footer(f, se); 1395 if (ret < 0) { 1396 qemu_file_set_error(f, ret); 1397 return -1; 1398 } 1399 } 1400 1401 return 0; 1402 } 1403 1404 int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f, 1405 bool in_postcopy, 1406 bool inactivate_disks) 1407 { 1408 MigrationState *ms = migrate_get_current(); 1409 JSONWriter *vmdesc = ms->vmdesc; 1410 int vmdesc_len; 1411 SaveStateEntry *se; 1412 int ret; 1413 1414 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1415 if (se->vmsd && se->vmsd->early_setup) { 1416 /* Already saved during qemu_savevm_state_setup(). */ 1417 continue; 1418 } 1419 1420 ret = vmstate_save(f, se, vmdesc); 1421 if (ret) { 1422 qemu_file_set_error(f, ret); 1423 return ret; 1424 } 1425 } 1426 1427 if (inactivate_disks) { 1428 /* Inactivate before sending QEMU_VM_EOF so that the 1429 * bdrv_activate_all() on the other end won't fail. */ 1430 ret = bdrv_inactivate_all(); 1431 if (ret) { 1432 error_report("%s: bdrv_inactivate_all() failed (%d)", 1433 __func__, ret); 1434 qemu_file_set_error(f, ret); 1435 return ret; 1436 } 1437 } 1438 if (!in_postcopy) { 1439 /* Postcopy stream will still be going */ 1440 qemu_put_byte(f, QEMU_VM_EOF); 1441 } 1442 1443 json_writer_end_array(vmdesc); 1444 json_writer_end_object(vmdesc); 1445 vmdesc_len = strlen(json_writer_get(vmdesc)); 1446 1447 if (should_send_vmdesc()) { 1448 qemu_put_byte(f, QEMU_VM_VMDESCRIPTION); 1449 qemu_put_be32(f, vmdesc_len); 1450 qemu_put_buffer(f, (uint8_t *)json_writer_get(vmdesc), vmdesc_len); 1451 } 1452 1453 /* Free it now to detect any inconsistencies. */ 1454 json_writer_free(vmdesc); 1455 ms->vmdesc = NULL; 1456 1457 return 0; 1458 } 1459 1460 int qemu_savevm_state_complete_precopy(QEMUFile *f, bool iterable_only, 1461 bool inactivate_disks) 1462 { 1463 int ret; 1464 Error *local_err = NULL; 1465 bool in_postcopy = migration_in_postcopy(); 1466 1467 if (precopy_notify(PRECOPY_NOTIFY_COMPLETE, &local_err)) { 1468 error_report_err(local_err); 1469 } 1470 1471 trace_savevm_state_complete_precopy(); 1472 1473 cpu_synchronize_all_states(); 1474 1475 if (!in_postcopy || iterable_only) { 1476 ret = qemu_savevm_state_complete_precopy_iterable(f, in_postcopy); 1477 if (ret) { 1478 return ret; 1479 } 1480 } 1481 1482 if (iterable_only) { 1483 goto flush; 1484 } 1485 1486 ret = qemu_savevm_state_complete_precopy_non_iterable(f, in_postcopy, 1487 inactivate_disks); 1488 if (ret) { 1489 return ret; 1490 } 1491 1492 flush: 1493 qemu_fflush(f); 1494 return 0; 1495 } 1496 1497 /* Give an estimate of the amount left to be transferred, 1498 * the result is split into the amount for units that can and 1499 * for units that can't do postcopy. 1500 */ 1501 void qemu_savevm_state_pending_estimate(uint64_t *res_precopy_only, 1502 uint64_t *res_compatible, 1503 uint64_t *res_postcopy_only) 1504 { 1505 SaveStateEntry *se; 1506 1507 *res_precopy_only = 0; 1508 *res_compatible = 0; 1509 *res_postcopy_only = 0; 1510 1511 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1512 if (!se->ops || !se->ops->state_pending_exact) { 1513 continue; 1514 } 1515 if (se->ops->is_active) { 1516 if (!se->ops->is_active(se->opaque)) { 1517 continue; 1518 } 1519 } 1520 se->ops->state_pending_exact(se->opaque, 1521 res_precopy_only, res_compatible, 1522 res_postcopy_only); 1523 } 1524 } 1525 1526 void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only, 1527 uint64_t *res_compatible, 1528 uint64_t *res_postcopy_only) 1529 { 1530 SaveStateEntry *se; 1531 1532 *res_precopy_only = 0; 1533 *res_compatible = 0; 1534 *res_postcopy_only = 0; 1535 1536 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1537 if (!se->ops || !se->ops->state_pending_estimate) { 1538 continue; 1539 } 1540 if (se->ops->is_active) { 1541 if (!se->ops->is_active(se->opaque)) { 1542 continue; 1543 } 1544 } 1545 se->ops->state_pending_estimate(se->opaque, 1546 res_precopy_only, res_compatible, 1547 res_postcopy_only); 1548 } 1549 } 1550 1551 void qemu_savevm_state_cleanup(void) 1552 { 1553 SaveStateEntry *se; 1554 Error *local_err = NULL; 1555 1556 if (precopy_notify(PRECOPY_NOTIFY_CLEANUP, &local_err)) { 1557 error_report_err(local_err); 1558 } 1559 1560 trace_savevm_state_cleanup(); 1561 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1562 if (se->ops && se->ops->save_cleanup) { 1563 se->ops->save_cleanup(se->opaque); 1564 } 1565 } 1566 } 1567 1568 static int qemu_savevm_state(QEMUFile *f, Error **errp) 1569 { 1570 int ret; 1571 MigrationState *ms = migrate_get_current(); 1572 MigrationStatus status; 1573 1574 if (migration_is_running(ms->state)) { 1575 error_setg(errp, QERR_MIGRATION_ACTIVE); 1576 return -EINVAL; 1577 } 1578 1579 if (migrate_use_block()) { 1580 error_setg(errp, "Block migration and snapshots are incompatible"); 1581 return -EINVAL; 1582 } 1583 1584 migrate_init(ms); 1585 memset(&ram_counters, 0, sizeof(ram_counters)); 1586 memset(&compression_counters, 0, sizeof(compression_counters)); 1587 ms->to_dst_file = f; 1588 1589 qemu_mutex_unlock_iothread(); 1590 qemu_savevm_state_header(f); 1591 qemu_savevm_state_setup(f); 1592 qemu_mutex_lock_iothread(); 1593 1594 while (qemu_file_get_error(f) == 0) { 1595 if (qemu_savevm_state_iterate(f, false) > 0) { 1596 break; 1597 } 1598 } 1599 1600 ret = qemu_file_get_error(f); 1601 if (ret == 0) { 1602 qemu_savevm_state_complete_precopy(f, false, false); 1603 ret = qemu_file_get_error(f); 1604 } 1605 qemu_savevm_state_cleanup(); 1606 if (ret != 0) { 1607 error_setg_errno(errp, -ret, "Error while writing VM state"); 1608 } 1609 1610 if (ret != 0) { 1611 status = MIGRATION_STATUS_FAILED; 1612 } else { 1613 status = MIGRATION_STATUS_COMPLETED; 1614 } 1615 migrate_set_state(&ms->state, MIGRATION_STATUS_SETUP, status); 1616 1617 /* f is outer parameter, it should not stay in global migration state after 1618 * this function finished */ 1619 ms->to_dst_file = NULL; 1620 1621 return ret; 1622 } 1623 1624 void qemu_savevm_live_state(QEMUFile *f) 1625 { 1626 /* save QEMU_VM_SECTION_END section */ 1627 qemu_savevm_state_complete_precopy(f, true, false); 1628 qemu_put_byte(f, QEMU_VM_EOF); 1629 } 1630 1631 int qemu_save_device_state(QEMUFile *f) 1632 { 1633 SaveStateEntry *se; 1634 1635 if (!migration_in_colo_state()) { 1636 qemu_put_be32(f, QEMU_VM_FILE_MAGIC); 1637 qemu_put_be32(f, QEMU_VM_FILE_VERSION); 1638 } 1639 cpu_synchronize_all_states(); 1640 1641 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1642 int ret; 1643 1644 if (se->is_ram) { 1645 continue; 1646 } 1647 ret = vmstate_save(f, se, NULL); 1648 if (ret) { 1649 return ret; 1650 } 1651 } 1652 1653 qemu_put_byte(f, QEMU_VM_EOF); 1654 1655 return qemu_file_get_error(f); 1656 } 1657 1658 static SaveStateEntry *find_se(const char *idstr, uint32_t instance_id) 1659 { 1660 SaveStateEntry *se; 1661 1662 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 1663 if (!strcmp(se->idstr, idstr) && 1664 (instance_id == se->instance_id || 1665 instance_id == se->alias_id)) 1666 return se; 1667 /* Migrating from an older version? */ 1668 if (strstr(se->idstr, idstr) && se->compat) { 1669 if (!strcmp(se->compat->idstr, idstr) && 1670 (instance_id == se->compat->instance_id || 1671 instance_id == se->alias_id)) 1672 return se; 1673 } 1674 } 1675 return NULL; 1676 } 1677 1678 enum LoadVMExitCodes { 1679 /* Allow a command to quit all layers of nested loadvm loops */ 1680 LOADVM_QUIT = 1, 1681 }; 1682 1683 /* ------ incoming postcopy messages ------ */ 1684 /* 'advise' arrives before any transfers just to tell us that a postcopy 1685 * *might* happen - it might be skipped if precopy transferred everything 1686 * quickly. 1687 */ 1688 static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis, 1689 uint16_t len) 1690 { 1691 PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_ADVISE); 1692 uint64_t remote_pagesize_summary, local_pagesize_summary, remote_tps; 1693 size_t page_size = qemu_target_page_size(); 1694 Error *local_err = NULL; 1695 1696 trace_loadvm_postcopy_handle_advise(); 1697 if (ps != POSTCOPY_INCOMING_NONE) { 1698 error_report("CMD_POSTCOPY_ADVISE in wrong postcopy state (%d)", ps); 1699 return -1; 1700 } 1701 1702 switch (len) { 1703 case 0: 1704 if (migrate_postcopy_ram()) { 1705 error_report("RAM postcopy is enabled but have 0 byte advise"); 1706 return -EINVAL; 1707 } 1708 return 0; 1709 case 8 + 8: 1710 if (!migrate_postcopy_ram()) { 1711 error_report("RAM postcopy is disabled but have 16 byte advise"); 1712 return -EINVAL; 1713 } 1714 break; 1715 default: 1716 error_report("CMD_POSTCOPY_ADVISE invalid length (%d)", len); 1717 return -EINVAL; 1718 } 1719 1720 if (!postcopy_ram_supported_by_host(mis)) { 1721 postcopy_state_set(POSTCOPY_INCOMING_NONE); 1722 return -1; 1723 } 1724 1725 remote_pagesize_summary = qemu_get_be64(mis->from_src_file); 1726 local_pagesize_summary = ram_pagesize_summary(); 1727 1728 if (remote_pagesize_summary != local_pagesize_summary) { 1729 /* 1730 * This detects two potential causes of mismatch: 1731 * a) A mismatch in host page sizes 1732 * Some combinations of mismatch are probably possible but it gets 1733 * a bit more complicated. In particular we need to place whole 1734 * host pages on the dest at once, and we need to ensure that we 1735 * handle dirtying to make sure we never end up sending part of 1736 * a hostpage on it's own. 1737 * b) The use of different huge page sizes on source/destination 1738 * a more fine grain test is performed during RAM block migration 1739 * but this test here causes a nice early clear failure, and 1740 * also fails when passed to an older qemu that doesn't 1741 * do huge pages. 1742 */ 1743 error_report("Postcopy needs matching RAM page sizes (s=%" PRIx64 1744 " d=%" PRIx64 ")", 1745 remote_pagesize_summary, local_pagesize_summary); 1746 return -1; 1747 } 1748 1749 remote_tps = qemu_get_be64(mis->from_src_file); 1750 if (remote_tps != page_size) { 1751 /* 1752 * Again, some differences could be dealt with, but for now keep it 1753 * simple. 1754 */ 1755 error_report("Postcopy needs matching target page sizes (s=%d d=%zd)", 1756 (int)remote_tps, page_size); 1757 return -1; 1758 } 1759 1760 if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_ADVISE, &local_err)) { 1761 error_report_err(local_err); 1762 return -1; 1763 } 1764 1765 if (ram_postcopy_incoming_init(mis)) { 1766 return -1; 1767 } 1768 1769 return 0; 1770 } 1771 1772 /* After postcopy we will be told to throw some pages away since they're 1773 * dirty and will have to be demand fetched. Must happen before CPU is 1774 * started. 1775 * There can be 0..many of these messages, each encoding multiple pages. 1776 */ 1777 static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis, 1778 uint16_t len) 1779 { 1780 int tmp; 1781 char ramid[256]; 1782 PostcopyState ps = postcopy_state_get(); 1783 1784 trace_loadvm_postcopy_ram_handle_discard(); 1785 1786 switch (ps) { 1787 case POSTCOPY_INCOMING_ADVISE: 1788 /* 1st discard */ 1789 tmp = postcopy_ram_prepare_discard(mis); 1790 if (tmp) { 1791 return tmp; 1792 } 1793 break; 1794 1795 case POSTCOPY_INCOMING_DISCARD: 1796 /* Expected state */ 1797 break; 1798 1799 default: 1800 error_report("CMD_POSTCOPY_RAM_DISCARD in wrong postcopy state (%d)", 1801 ps); 1802 return -1; 1803 } 1804 /* We're expecting a 1805 * Version (0) 1806 * a RAM ID string (length byte, name, 0 term) 1807 * then at least 1 16 byte chunk 1808 */ 1809 if (len < (1 + 1 + 1 + 1 + 2 * 8)) { 1810 error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len); 1811 return -1; 1812 } 1813 1814 tmp = qemu_get_byte(mis->from_src_file); 1815 if (tmp != postcopy_ram_discard_version) { 1816 error_report("CMD_POSTCOPY_RAM_DISCARD invalid version (%d)", tmp); 1817 return -1; 1818 } 1819 1820 if (!qemu_get_counted_string(mis->from_src_file, ramid)) { 1821 error_report("CMD_POSTCOPY_RAM_DISCARD Failed to read RAMBlock ID"); 1822 return -1; 1823 } 1824 tmp = qemu_get_byte(mis->from_src_file); 1825 if (tmp != 0) { 1826 error_report("CMD_POSTCOPY_RAM_DISCARD missing nil (%d)", tmp); 1827 return -1; 1828 } 1829 1830 len -= 3 + strlen(ramid); 1831 if (len % 16) { 1832 error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len); 1833 return -1; 1834 } 1835 trace_loadvm_postcopy_ram_handle_discard_header(ramid, len); 1836 while (len) { 1837 uint64_t start_addr, block_length; 1838 start_addr = qemu_get_be64(mis->from_src_file); 1839 block_length = qemu_get_be64(mis->from_src_file); 1840 1841 len -= 16; 1842 int ret = ram_discard_range(ramid, start_addr, block_length); 1843 if (ret) { 1844 return ret; 1845 } 1846 } 1847 trace_loadvm_postcopy_ram_handle_discard_end(); 1848 1849 return 0; 1850 } 1851 1852 /* 1853 * Triggered by a postcopy_listen command; this thread takes over reading 1854 * the input stream, leaving the main thread free to carry on loading the rest 1855 * of the device state (from RAM). 1856 * (TODO:This could do with being in a postcopy file - but there again it's 1857 * just another input loop, not that postcopy specific) 1858 */ 1859 static void *postcopy_ram_listen_thread(void *opaque) 1860 { 1861 MigrationIncomingState *mis = migration_incoming_get_current(); 1862 QEMUFile *f = mis->from_src_file; 1863 int load_res; 1864 MigrationState *migr = migrate_get_current(); 1865 1866 object_ref(OBJECT(migr)); 1867 1868 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, 1869 MIGRATION_STATUS_POSTCOPY_ACTIVE); 1870 qemu_sem_post(&mis->thread_sync_sem); 1871 trace_postcopy_ram_listen_thread_start(); 1872 1873 rcu_register_thread(); 1874 /* 1875 * Because we're a thread and not a coroutine we can't yield 1876 * in qemu_file, and thus we must be blocking now. 1877 */ 1878 qemu_file_set_blocking(f, true); 1879 load_res = qemu_loadvm_state_main(f, mis); 1880 1881 /* 1882 * This is tricky, but, mis->from_src_file can change after it 1883 * returns, when postcopy recovery happened. In the future, we may 1884 * want a wrapper for the QEMUFile handle. 1885 */ 1886 f = mis->from_src_file; 1887 1888 /* And non-blocking again so we don't block in any cleanup */ 1889 qemu_file_set_blocking(f, false); 1890 1891 trace_postcopy_ram_listen_thread_exit(); 1892 if (load_res < 0) { 1893 qemu_file_set_error(f, load_res); 1894 dirty_bitmap_mig_cancel_incoming(); 1895 if (postcopy_state_get() == POSTCOPY_INCOMING_RUNNING && 1896 !migrate_postcopy_ram() && migrate_dirty_bitmaps()) 1897 { 1898 error_report("%s: loadvm failed during postcopy: %d. All states " 1899 "are migrated except dirty bitmaps. Some dirty " 1900 "bitmaps may be lost, and present migrated dirty " 1901 "bitmaps are correctly migrated and valid.", 1902 __func__, load_res); 1903 load_res = 0; /* prevent further exit() */ 1904 } else { 1905 error_report("%s: loadvm failed: %d", __func__, load_res); 1906 migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, 1907 MIGRATION_STATUS_FAILED); 1908 } 1909 } 1910 if (load_res >= 0) { 1911 /* 1912 * This looks good, but it's possible that the device loading in the 1913 * main thread hasn't finished yet, and so we might not be in 'RUN' 1914 * state yet; wait for the end of the main thread. 1915 */ 1916 qemu_event_wait(&mis->main_thread_load_event); 1917 } 1918 postcopy_ram_incoming_cleanup(mis); 1919 1920 if (load_res < 0) { 1921 /* 1922 * If something went wrong then we have a bad state so exit; 1923 * depending how far we got it might be possible at this point 1924 * to leave the guest running and fire MCEs for pages that never 1925 * arrived as a desperate recovery step. 1926 */ 1927 rcu_unregister_thread(); 1928 exit(EXIT_FAILURE); 1929 } 1930 1931 migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, 1932 MIGRATION_STATUS_COMPLETED); 1933 /* 1934 * If everything has worked fine, then the main thread has waited 1935 * for us to start, and we're the last use of the mis. 1936 * (If something broke then qemu will have to exit anyway since it's 1937 * got a bad migration state). 1938 */ 1939 migration_incoming_state_destroy(); 1940 qemu_loadvm_state_cleanup(); 1941 1942 rcu_unregister_thread(); 1943 mis->have_listen_thread = false; 1944 postcopy_state_set(POSTCOPY_INCOMING_END); 1945 1946 object_unref(OBJECT(migr)); 1947 1948 return NULL; 1949 } 1950 1951 /* After this message we must be able to immediately receive postcopy data */ 1952 static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis) 1953 { 1954 PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_LISTENING); 1955 Error *local_err = NULL; 1956 1957 trace_loadvm_postcopy_handle_listen("enter"); 1958 1959 if (ps != POSTCOPY_INCOMING_ADVISE && ps != POSTCOPY_INCOMING_DISCARD) { 1960 error_report("CMD_POSTCOPY_LISTEN in wrong postcopy state (%d)", ps); 1961 return -1; 1962 } 1963 if (ps == POSTCOPY_INCOMING_ADVISE) { 1964 /* 1965 * A rare case, we entered listen without having to do any discards, 1966 * so do the setup that's normally done at the time of the 1st discard. 1967 */ 1968 if (migrate_postcopy_ram()) { 1969 postcopy_ram_prepare_discard(mis); 1970 } 1971 } 1972 1973 trace_loadvm_postcopy_handle_listen("after discard"); 1974 1975 /* 1976 * Sensitise RAM - can now generate requests for blocks that don't exist 1977 * However, at this point the CPU shouldn't be running, and the IO 1978 * shouldn't be doing anything yet so don't actually expect requests 1979 */ 1980 if (migrate_postcopy_ram()) { 1981 if (postcopy_ram_incoming_setup(mis)) { 1982 postcopy_ram_incoming_cleanup(mis); 1983 return -1; 1984 } 1985 } 1986 1987 trace_loadvm_postcopy_handle_listen("after uffd"); 1988 1989 if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_LISTEN, &local_err)) { 1990 error_report_err(local_err); 1991 return -1; 1992 } 1993 1994 mis->have_listen_thread = true; 1995 postcopy_thread_create(mis, &mis->listen_thread, "postcopy/listen", 1996 postcopy_ram_listen_thread, QEMU_THREAD_DETACHED); 1997 trace_loadvm_postcopy_handle_listen("return"); 1998 1999 return 0; 2000 } 2001 2002 static void loadvm_postcopy_handle_run_bh(void *opaque) 2003 { 2004 Error *local_err = NULL; 2005 MigrationIncomingState *mis = opaque; 2006 2007 trace_loadvm_postcopy_handle_run_bh("enter"); 2008 2009 /* TODO we should move all of this lot into postcopy_ram.c or a shared code 2010 * in migration.c 2011 */ 2012 cpu_synchronize_all_post_init(); 2013 2014 trace_loadvm_postcopy_handle_run_bh("after cpu sync"); 2015 2016 qemu_announce_self(&mis->announce_timer, migrate_announce_params()); 2017 2018 trace_loadvm_postcopy_handle_run_bh("after announce"); 2019 2020 /* Make sure all file formats throw away their mutable metadata. 2021 * If we get an error here, just don't restart the VM yet. */ 2022 bdrv_activate_all(&local_err); 2023 if (local_err) { 2024 error_report_err(local_err); 2025 local_err = NULL; 2026 autostart = false; 2027 } 2028 2029 trace_loadvm_postcopy_handle_run_bh("after invalidate cache"); 2030 2031 dirty_bitmap_mig_before_vm_start(); 2032 2033 if (autostart) { 2034 /* Hold onto your hats, starting the CPU */ 2035 vm_start(); 2036 } else { 2037 /* leave it paused and let management decide when to start the CPU */ 2038 runstate_set(RUN_STATE_PAUSED); 2039 } 2040 2041 qemu_bh_delete(mis->bh); 2042 2043 trace_loadvm_postcopy_handle_run_bh("return"); 2044 } 2045 2046 /* After all discards we can start running and asking for pages */ 2047 static int loadvm_postcopy_handle_run(MigrationIncomingState *mis) 2048 { 2049 PostcopyState ps = postcopy_state_get(); 2050 2051 trace_loadvm_postcopy_handle_run(); 2052 if (ps != POSTCOPY_INCOMING_LISTENING) { 2053 error_report("CMD_POSTCOPY_RUN in wrong postcopy state (%d)", ps); 2054 return -1; 2055 } 2056 2057 postcopy_state_set(POSTCOPY_INCOMING_RUNNING); 2058 mis->bh = qemu_bh_new(loadvm_postcopy_handle_run_bh, mis); 2059 qemu_bh_schedule(mis->bh); 2060 2061 /* We need to finish reading the stream from the package 2062 * and also stop reading anything more from the stream that loaded the 2063 * package (since it's now being read by the listener thread). 2064 * LOADVM_QUIT will quit all the layers of nested loadvm loops. 2065 */ 2066 return LOADVM_QUIT; 2067 } 2068 2069 /* We must be with page_request_mutex held */ 2070 static gboolean postcopy_sync_page_req(gpointer key, gpointer value, 2071 gpointer data) 2072 { 2073 MigrationIncomingState *mis = data; 2074 void *host_addr = (void *) key; 2075 ram_addr_t rb_offset; 2076 RAMBlock *rb; 2077 int ret; 2078 2079 rb = qemu_ram_block_from_host(host_addr, true, &rb_offset); 2080 if (!rb) { 2081 /* 2082 * This should _never_ happen. However be nice for a migrating VM to 2083 * not crash/assert. Post an error (note: intended to not use *_once 2084 * because we do want to see all the illegal addresses; and this can 2085 * never be triggered by the guest so we're safe) and move on next. 2086 */ 2087 error_report("%s: illegal host addr %p", __func__, host_addr); 2088 /* Try the next entry */ 2089 return FALSE; 2090 } 2091 2092 ret = migrate_send_rp_message_req_pages(mis, rb, rb_offset); 2093 if (ret) { 2094 /* Please refer to above comment. */ 2095 error_report("%s: send rp message failed for addr %p", 2096 __func__, host_addr); 2097 return FALSE; 2098 } 2099 2100 trace_postcopy_page_req_sync(host_addr); 2101 2102 return FALSE; 2103 } 2104 2105 static void migrate_send_rp_req_pages_pending(MigrationIncomingState *mis) 2106 { 2107 WITH_QEMU_LOCK_GUARD(&mis->page_request_mutex) { 2108 g_tree_foreach(mis->page_requested, postcopy_sync_page_req, mis); 2109 } 2110 } 2111 2112 static int loadvm_postcopy_handle_resume(MigrationIncomingState *mis) 2113 { 2114 if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) { 2115 error_report("%s: illegal resume received", __func__); 2116 /* Don't fail the load, only for this. */ 2117 return 0; 2118 } 2119 2120 /* 2121 * Reset the last_rb before we resend any page req to source again, since 2122 * the source should have it reset already. 2123 */ 2124 mis->last_rb = NULL; 2125 2126 /* 2127 * This means source VM is ready to resume the postcopy migration. 2128 */ 2129 migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_RECOVER, 2130 MIGRATION_STATUS_POSTCOPY_ACTIVE); 2131 2132 trace_loadvm_postcopy_handle_resume(); 2133 2134 /* Tell source that "we are ready" */ 2135 migrate_send_rp_resume_ack(mis, MIGRATION_RESUME_ACK_VALUE); 2136 2137 /* 2138 * After a postcopy recovery, the source should have lost the postcopy 2139 * queue, or potentially the requested pages could have been lost during 2140 * the network down phase. Let's re-sync with the source VM by re-sending 2141 * all the pending pages that we eagerly need, so these threads won't get 2142 * blocked too long due to the recovery. 2143 * 2144 * Without this procedure, the faulted destination VM threads (waiting for 2145 * page requests right before the postcopy is interrupted) can keep hanging 2146 * until the pages are sent by the source during the background copying of 2147 * pages, or another thread faulted on the same address accidentally. 2148 */ 2149 migrate_send_rp_req_pages_pending(mis); 2150 2151 /* 2152 * It's time to switch state and release the fault thread to continue 2153 * service page faults. Note that this should be explicitly after the 2154 * above call to migrate_send_rp_req_pages_pending(). In short: 2155 * migrate_send_rp_message_req_pages() is not thread safe, yet. 2156 */ 2157 qemu_sem_post(&mis->postcopy_pause_sem_fault); 2158 2159 if (migrate_postcopy_preempt()) { 2160 /* The channel should already be setup again; make sure of it */ 2161 assert(mis->postcopy_qemufile_dst); 2162 /* Kick the fast ram load thread too */ 2163 qemu_sem_post(&mis->postcopy_pause_sem_fast_load); 2164 } 2165 2166 return 0; 2167 } 2168 2169 /** 2170 * Immediately following this command is a blob of data containing an embedded 2171 * chunk of migration stream; read it and load it. 2172 * 2173 * @mis: Incoming state 2174 * @length: Length of packaged data to read 2175 * 2176 * Returns: Negative values on error 2177 * 2178 */ 2179 static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) 2180 { 2181 int ret; 2182 size_t length; 2183 QIOChannelBuffer *bioc; 2184 2185 length = qemu_get_be32(mis->from_src_file); 2186 trace_loadvm_handle_cmd_packaged(length); 2187 2188 if (length > MAX_VM_CMD_PACKAGED_SIZE) { 2189 error_report("Unreasonably large packaged state: %zu", length); 2190 return -1; 2191 } 2192 2193 bioc = qio_channel_buffer_new(length); 2194 qio_channel_set_name(QIO_CHANNEL(bioc), "migration-loadvm-buffer"); 2195 ret = qemu_get_buffer(mis->from_src_file, 2196 bioc->data, 2197 length); 2198 if (ret != length) { 2199 object_unref(OBJECT(bioc)); 2200 error_report("CMD_PACKAGED: Buffer receive fail ret=%d length=%zu", 2201 ret, length); 2202 return (ret < 0) ? ret : -EAGAIN; 2203 } 2204 bioc->usage += length; 2205 trace_loadvm_handle_cmd_packaged_received(ret); 2206 2207 QEMUFile *packf = qemu_file_new_input(QIO_CHANNEL(bioc)); 2208 2209 ret = qemu_loadvm_state_main(packf, mis); 2210 trace_loadvm_handle_cmd_packaged_main(ret); 2211 qemu_fclose(packf); 2212 object_unref(OBJECT(bioc)); 2213 2214 return ret; 2215 } 2216 2217 /* 2218 * Handle request that source requests for recved_bitmap on 2219 * destination. Payload format: 2220 * 2221 * len (1 byte) + ramblock_name (<255 bytes) 2222 */ 2223 static int loadvm_handle_recv_bitmap(MigrationIncomingState *mis, 2224 uint16_t len) 2225 { 2226 QEMUFile *file = mis->from_src_file; 2227 RAMBlock *rb; 2228 char block_name[256]; 2229 size_t cnt; 2230 2231 cnt = qemu_get_counted_string(file, block_name); 2232 if (!cnt) { 2233 error_report("%s: failed to read block name", __func__); 2234 return -EINVAL; 2235 } 2236 2237 /* Validate before using the data */ 2238 if (qemu_file_get_error(file)) { 2239 return qemu_file_get_error(file); 2240 } 2241 2242 if (len != cnt + 1) { 2243 error_report("%s: invalid payload length (%d)", __func__, len); 2244 return -EINVAL; 2245 } 2246 2247 rb = qemu_ram_block_by_name(block_name); 2248 if (!rb) { 2249 error_report("%s: block '%s' not found", __func__, block_name); 2250 return -EINVAL; 2251 } 2252 2253 migrate_send_rp_recv_bitmap(mis, block_name); 2254 2255 trace_loadvm_handle_recv_bitmap(block_name); 2256 2257 return 0; 2258 } 2259 2260 static int loadvm_process_enable_colo(MigrationIncomingState *mis) 2261 { 2262 int ret = migration_incoming_enable_colo(); 2263 2264 if (!ret) { 2265 ret = colo_init_ram_cache(); 2266 if (ret) { 2267 migration_incoming_disable_colo(); 2268 } 2269 } 2270 return ret; 2271 } 2272 2273 /* 2274 * Process an incoming 'QEMU_VM_COMMAND' 2275 * 0 just a normal return 2276 * LOADVM_QUIT All good, but exit the loop 2277 * <0 Error 2278 */ 2279 static int loadvm_process_command(QEMUFile *f) 2280 { 2281 MigrationIncomingState *mis = migration_incoming_get_current(); 2282 uint16_t cmd; 2283 uint16_t len; 2284 uint32_t tmp32; 2285 2286 cmd = qemu_get_be16(f); 2287 len = qemu_get_be16(f); 2288 2289 /* Check validity before continue processing of cmds */ 2290 if (qemu_file_get_error(f)) { 2291 return qemu_file_get_error(f); 2292 } 2293 2294 if (cmd >= MIG_CMD_MAX || cmd == MIG_CMD_INVALID) { 2295 error_report("MIG_CMD 0x%x unknown (len 0x%x)", cmd, len); 2296 return -EINVAL; 2297 } 2298 2299 trace_loadvm_process_command(mig_cmd_args[cmd].name, len); 2300 2301 if (mig_cmd_args[cmd].len != -1 && mig_cmd_args[cmd].len != len) { 2302 error_report("%s received with bad length - expecting %zu, got %d", 2303 mig_cmd_args[cmd].name, 2304 (size_t)mig_cmd_args[cmd].len, len); 2305 return -ERANGE; 2306 } 2307 2308 switch (cmd) { 2309 case MIG_CMD_OPEN_RETURN_PATH: 2310 if (mis->to_src_file) { 2311 error_report("CMD_OPEN_RETURN_PATH called when RP already open"); 2312 /* Not really a problem, so don't give up */ 2313 return 0; 2314 } 2315 mis->to_src_file = qemu_file_get_return_path(f); 2316 if (!mis->to_src_file) { 2317 error_report("CMD_OPEN_RETURN_PATH failed"); 2318 return -1; 2319 } 2320 break; 2321 2322 case MIG_CMD_PING: 2323 tmp32 = qemu_get_be32(f); 2324 trace_loadvm_process_command_ping(tmp32); 2325 if (!mis->to_src_file) { 2326 error_report("CMD_PING (0x%x) received with no return path", 2327 tmp32); 2328 return -1; 2329 } 2330 migrate_send_rp_pong(mis, tmp32); 2331 break; 2332 2333 case MIG_CMD_PACKAGED: 2334 return loadvm_handle_cmd_packaged(mis); 2335 2336 case MIG_CMD_POSTCOPY_ADVISE: 2337 return loadvm_postcopy_handle_advise(mis, len); 2338 2339 case MIG_CMD_POSTCOPY_LISTEN: 2340 return loadvm_postcopy_handle_listen(mis); 2341 2342 case MIG_CMD_POSTCOPY_RUN: 2343 return loadvm_postcopy_handle_run(mis); 2344 2345 case MIG_CMD_POSTCOPY_RAM_DISCARD: 2346 return loadvm_postcopy_ram_handle_discard(mis, len); 2347 2348 case MIG_CMD_POSTCOPY_RESUME: 2349 return loadvm_postcopy_handle_resume(mis); 2350 2351 case MIG_CMD_RECV_BITMAP: 2352 return loadvm_handle_recv_bitmap(mis, len); 2353 2354 case MIG_CMD_ENABLE_COLO: 2355 return loadvm_process_enable_colo(mis); 2356 } 2357 2358 return 0; 2359 } 2360 2361 /* 2362 * Read a footer off the wire and check that it matches the expected section 2363 * 2364 * Returns: true if the footer was good 2365 * false if there is a problem (and calls error_report to say why) 2366 */ 2367 static bool check_section_footer(QEMUFile *f, SaveStateEntry *se) 2368 { 2369 int ret; 2370 uint8_t read_mark; 2371 uint32_t read_section_id; 2372 2373 if (!migrate_get_current()->send_section_footer) { 2374 /* No footer to check */ 2375 return true; 2376 } 2377 2378 read_mark = qemu_get_byte(f); 2379 2380 ret = qemu_file_get_error(f); 2381 if (ret) { 2382 error_report("%s: Read section footer failed: %d", 2383 __func__, ret); 2384 return false; 2385 } 2386 2387 if (read_mark != QEMU_VM_SECTION_FOOTER) { 2388 error_report("Missing section footer for %s", se->idstr); 2389 return false; 2390 } 2391 2392 read_section_id = qemu_get_be32(f); 2393 if (read_section_id != se->load_section_id) { 2394 error_report("Mismatched section id in footer for %s -" 2395 " read 0x%x expected 0x%x", 2396 se->idstr, read_section_id, se->load_section_id); 2397 return false; 2398 } 2399 2400 /* All good */ 2401 return true; 2402 } 2403 2404 static int 2405 qemu_loadvm_section_start_full(QEMUFile *f, MigrationIncomingState *mis) 2406 { 2407 uint32_t instance_id, version_id, section_id; 2408 SaveStateEntry *se; 2409 char idstr[256]; 2410 int ret; 2411 2412 /* Read section start */ 2413 section_id = qemu_get_be32(f); 2414 if (!qemu_get_counted_string(f, idstr)) { 2415 error_report("Unable to read ID string for section %u", 2416 section_id); 2417 return -EINVAL; 2418 } 2419 instance_id = qemu_get_be32(f); 2420 version_id = qemu_get_be32(f); 2421 2422 ret = qemu_file_get_error(f); 2423 if (ret) { 2424 error_report("%s: Failed to read instance/version ID: %d", 2425 __func__, ret); 2426 return ret; 2427 } 2428 2429 trace_qemu_loadvm_state_section_startfull(section_id, idstr, 2430 instance_id, version_id); 2431 /* Find savevm section */ 2432 se = find_se(idstr, instance_id); 2433 if (se == NULL) { 2434 error_report("Unknown savevm section or instance '%s' %"PRIu32". " 2435 "Make sure that your current VM setup matches your " 2436 "saved VM setup, including any hotplugged devices", 2437 idstr, instance_id); 2438 return -EINVAL; 2439 } 2440 2441 /* Validate version */ 2442 if (version_id > se->version_id) { 2443 error_report("savevm: unsupported version %d for '%s' v%d", 2444 version_id, idstr, se->version_id); 2445 return -EINVAL; 2446 } 2447 se->load_version_id = version_id; 2448 se->load_section_id = section_id; 2449 2450 /* Validate if it is a device's state */ 2451 if (xen_enabled() && se->is_ram) { 2452 error_report("loadvm: %s RAM loading not allowed on Xen", idstr); 2453 return -EINVAL; 2454 } 2455 2456 ret = vmstate_load(f, se); 2457 if (ret < 0) { 2458 error_report("error while loading state for instance 0x%"PRIx32" of" 2459 " device '%s'", instance_id, idstr); 2460 return ret; 2461 } 2462 if (!check_section_footer(f, se)) { 2463 return -EINVAL; 2464 } 2465 2466 return 0; 2467 } 2468 2469 static int 2470 qemu_loadvm_section_part_end(QEMUFile *f, MigrationIncomingState *mis) 2471 { 2472 uint32_t section_id; 2473 SaveStateEntry *se; 2474 int ret; 2475 2476 section_id = qemu_get_be32(f); 2477 2478 ret = qemu_file_get_error(f); 2479 if (ret) { 2480 error_report("%s: Failed to read section ID: %d", 2481 __func__, ret); 2482 return ret; 2483 } 2484 2485 trace_qemu_loadvm_state_section_partend(section_id); 2486 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 2487 if (se->load_section_id == section_id) { 2488 break; 2489 } 2490 } 2491 if (se == NULL) { 2492 error_report("Unknown savevm section %d", section_id); 2493 return -EINVAL; 2494 } 2495 2496 ret = vmstate_load(f, se); 2497 if (ret < 0) { 2498 error_report("error while loading state section id %d(%s)", 2499 section_id, se->idstr); 2500 return ret; 2501 } 2502 if (!check_section_footer(f, se)) { 2503 return -EINVAL; 2504 } 2505 2506 return 0; 2507 } 2508 2509 static int qemu_loadvm_state_header(QEMUFile *f) 2510 { 2511 unsigned int v; 2512 int ret; 2513 2514 v = qemu_get_be32(f); 2515 if (v != QEMU_VM_FILE_MAGIC) { 2516 error_report("Not a migration stream"); 2517 return -EINVAL; 2518 } 2519 2520 v = qemu_get_be32(f); 2521 if (v == QEMU_VM_FILE_VERSION_COMPAT) { 2522 error_report("SaveVM v2 format is obsolete and don't work anymore"); 2523 return -ENOTSUP; 2524 } 2525 if (v != QEMU_VM_FILE_VERSION) { 2526 error_report("Unsupported migration stream version"); 2527 return -ENOTSUP; 2528 } 2529 2530 if (migrate_get_current()->send_configuration) { 2531 if (qemu_get_byte(f) != QEMU_VM_CONFIGURATION) { 2532 error_report("Configuration section missing"); 2533 qemu_loadvm_state_cleanup(); 2534 return -EINVAL; 2535 } 2536 ret = vmstate_load_state(f, &vmstate_configuration, &savevm_state, 0); 2537 2538 if (ret) { 2539 qemu_loadvm_state_cleanup(); 2540 return ret; 2541 } 2542 } 2543 return 0; 2544 } 2545 2546 static int qemu_loadvm_state_setup(QEMUFile *f) 2547 { 2548 SaveStateEntry *se; 2549 int ret; 2550 2551 trace_loadvm_state_setup(); 2552 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 2553 if (!se->ops || !se->ops->load_setup) { 2554 continue; 2555 } 2556 if (se->ops->is_active) { 2557 if (!se->ops->is_active(se->opaque)) { 2558 continue; 2559 } 2560 } 2561 2562 ret = se->ops->load_setup(f, se->opaque); 2563 if (ret < 0) { 2564 qemu_file_set_error(f, ret); 2565 error_report("Load state of device %s failed", se->idstr); 2566 return ret; 2567 } 2568 } 2569 return 0; 2570 } 2571 2572 void qemu_loadvm_state_cleanup(void) 2573 { 2574 SaveStateEntry *se; 2575 2576 trace_loadvm_state_cleanup(); 2577 QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { 2578 if (se->ops && se->ops->load_cleanup) { 2579 se->ops->load_cleanup(se->opaque); 2580 } 2581 } 2582 } 2583 2584 /* Return true if we should continue the migration, or false. */ 2585 static bool postcopy_pause_incoming(MigrationIncomingState *mis) 2586 { 2587 int i; 2588 2589 trace_postcopy_pause_incoming(); 2590 2591 assert(migrate_postcopy_ram()); 2592 2593 /* 2594 * Unregister yank with either from/to src would work, since ioc behind it 2595 * is the same 2596 */ 2597 migration_ioc_unregister_yank_from_file(mis->from_src_file); 2598 2599 assert(mis->from_src_file); 2600 qemu_file_shutdown(mis->from_src_file); 2601 qemu_fclose(mis->from_src_file); 2602 mis->from_src_file = NULL; 2603 2604 assert(mis->to_src_file); 2605 qemu_file_shutdown(mis->to_src_file); 2606 qemu_mutex_lock(&mis->rp_mutex); 2607 qemu_fclose(mis->to_src_file); 2608 mis->to_src_file = NULL; 2609 qemu_mutex_unlock(&mis->rp_mutex); 2610 2611 /* 2612 * NOTE: this must happen before reset the PostcopyTmpPages below, 2613 * otherwise it's racy to reset those fields when the fast load thread 2614 * can be accessing it in parallel. 2615 */ 2616 if (mis->postcopy_qemufile_dst) { 2617 qemu_file_shutdown(mis->postcopy_qemufile_dst); 2618 /* Take the mutex to make sure the fast ram load thread halted */ 2619 qemu_mutex_lock(&mis->postcopy_prio_thread_mutex); 2620 migration_ioc_unregister_yank_from_file(mis->postcopy_qemufile_dst); 2621 qemu_fclose(mis->postcopy_qemufile_dst); 2622 mis->postcopy_qemufile_dst = NULL; 2623 qemu_mutex_unlock(&mis->postcopy_prio_thread_mutex); 2624 } 2625 2626 migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, 2627 MIGRATION_STATUS_POSTCOPY_PAUSED); 2628 2629 /* Notify the fault thread for the invalidated file handle */ 2630 postcopy_fault_thread_notify(mis); 2631 2632 /* 2633 * If network is interrupted, any temp page we received will be useless 2634 * because we didn't mark them as "received" in receivedmap. After a 2635 * proper recovery later (which will sync src dirty bitmap with receivedmap 2636 * on dest) these cached small pages will be resent again. 2637 */ 2638 for (i = 0; i < mis->postcopy_channels; i++) { 2639 postcopy_temp_page_reset(&mis->postcopy_tmp_pages[i]); 2640 } 2641 2642 error_report("Detected IO failure for postcopy. " 2643 "Migration paused."); 2644 2645 while (mis->state == MIGRATION_STATUS_POSTCOPY_PAUSED) { 2646 qemu_sem_wait(&mis->postcopy_pause_sem_dst); 2647 } 2648 2649 trace_postcopy_pause_incoming_continued(); 2650 2651 return true; 2652 } 2653 2654 int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis) 2655 { 2656 uint8_t section_type; 2657 int ret = 0; 2658 2659 retry: 2660 while (true) { 2661 section_type = qemu_get_byte(f); 2662 2663 ret = qemu_file_get_error_obj_any(f, mis->postcopy_qemufile_dst, NULL); 2664 if (ret) { 2665 break; 2666 } 2667 2668 trace_qemu_loadvm_state_section(section_type); 2669 switch (section_type) { 2670 case QEMU_VM_SECTION_START: 2671 case QEMU_VM_SECTION_FULL: 2672 ret = qemu_loadvm_section_start_full(f, mis); 2673 if (ret < 0) { 2674 goto out; 2675 } 2676 break; 2677 case QEMU_VM_SECTION_PART: 2678 case QEMU_VM_SECTION_END: 2679 ret = qemu_loadvm_section_part_end(f, mis); 2680 if (ret < 0) { 2681 goto out; 2682 } 2683 break; 2684 case QEMU_VM_COMMAND: 2685 ret = loadvm_process_command(f); 2686 trace_qemu_loadvm_state_section_command(ret); 2687 if ((ret < 0) || (ret == LOADVM_QUIT)) { 2688 goto out; 2689 } 2690 break; 2691 case QEMU_VM_EOF: 2692 /* This is the end of migration */ 2693 goto out; 2694 default: 2695 error_report("Unknown savevm section type %d", section_type); 2696 ret = -EINVAL; 2697 goto out; 2698 } 2699 } 2700 2701 out: 2702 if (ret < 0) { 2703 qemu_file_set_error(f, ret); 2704 2705 /* Cancel bitmaps incoming regardless of recovery */ 2706 dirty_bitmap_mig_cancel_incoming(); 2707 2708 /* 2709 * If we are during an active postcopy, then we pause instead 2710 * of bail out to at least keep the VM's dirty data. Note 2711 * that POSTCOPY_INCOMING_LISTENING stage is still not enough, 2712 * during which we're still receiving device states and we 2713 * still haven't yet started the VM on destination. 2714 * 2715 * Only RAM postcopy supports recovery. Still, if RAM postcopy is 2716 * enabled, canceled bitmaps postcopy will not affect RAM postcopy 2717 * recovering. 2718 */ 2719 if (postcopy_state_get() == POSTCOPY_INCOMING_RUNNING && 2720 migrate_postcopy_ram() && postcopy_pause_incoming(mis)) { 2721 /* Reset f to point to the newly created channel */ 2722 f = mis->from_src_file; 2723 goto retry; 2724 } 2725 } 2726 return ret; 2727 } 2728 2729 int qemu_loadvm_state(QEMUFile *f) 2730 { 2731 MigrationIncomingState *mis = migration_incoming_get_current(); 2732 Error *local_err = NULL; 2733 int ret; 2734 2735 if (qemu_savevm_state_blocked(&local_err)) { 2736 error_report_err(local_err); 2737 return -EINVAL; 2738 } 2739 2740 ret = qemu_loadvm_state_header(f); 2741 if (ret) { 2742 return ret; 2743 } 2744 2745 if (qemu_loadvm_state_setup(f) != 0) { 2746 return -EINVAL; 2747 } 2748 2749 cpu_synchronize_all_pre_loadvm(); 2750 2751 ret = qemu_loadvm_state_main(f, mis); 2752 qemu_event_set(&mis->main_thread_load_event); 2753 2754 trace_qemu_loadvm_state_post_main(ret); 2755 2756 if (mis->have_listen_thread) { 2757 /* Listen thread still going, can't clean up yet */ 2758 return ret; 2759 } 2760 2761 if (ret == 0) { 2762 ret = qemu_file_get_error(f); 2763 } 2764 2765 /* 2766 * Try to read in the VMDESC section as well, so that dumping tools that 2767 * intercept our migration stream have the chance to see it. 2768 */ 2769 2770 /* We've got to be careful; if we don't read the data and just shut the fd 2771 * then the sender can error if we close while it's still sending. 2772 * We also mustn't read data that isn't there; some transports (RDMA) 2773 * will stall waiting for that data when the source has already closed. 2774 */ 2775 if (ret == 0 && should_send_vmdesc()) { 2776 uint8_t *buf; 2777 uint32_t size; 2778 uint8_t section_type = qemu_get_byte(f); 2779 2780 if (section_type != QEMU_VM_VMDESCRIPTION) { 2781 error_report("Expected vmdescription section, but got %d", 2782 section_type); 2783 /* 2784 * It doesn't seem worth failing at this point since 2785 * we apparently have an otherwise valid VM state 2786 */ 2787 } else { 2788 buf = g_malloc(0x1000); 2789 size = qemu_get_be32(f); 2790 2791 while (size > 0) { 2792 uint32_t read_chunk = MIN(size, 0x1000); 2793 qemu_get_buffer(f, buf, read_chunk); 2794 size -= read_chunk; 2795 } 2796 g_free(buf); 2797 } 2798 } 2799 2800 qemu_loadvm_state_cleanup(); 2801 cpu_synchronize_all_post_init(); 2802 2803 return ret; 2804 } 2805 2806 int qemu_load_device_state(QEMUFile *f) 2807 { 2808 MigrationIncomingState *mis = migration_incoming_get_current(); 2809 int ret; 2810 2811 /* Load QEMU_VM_SECTION_FULL section */ 2812 ret = qemu_loadvm_state_main(f, mis); 2813 if (ret < 0) { 2814 error_report("Failed to load device state: %d", ret); 2815 return ret; 2816 } 2817 2818 cpu_synchronize_all_post_init(); 2819 return 0; 2820 } 2821 2822 bool save_snapshot(const char *name, bool overwrite, const char *vmstate, 2823 bool has_devices, strList *devices, Error **errp) 2824 { 2825 BlockDriverState *bs; 2826 QEMUSnapshotInfo sn1, *sn = &sn1; 2827 int ret = -1, ret2; 2828 QEMUFile *f; 2829 int saved_vm_running; 2830 uint64_t vm_state_size; 2831 g_autoptr(GDateTime) now = g_date_time_new_now_local(); 2832 AioContext *aio_context; 2833 2834 GLOBAL_STATE_CODE(); 2835 2836 if (migration_is_blocked(errp)) { 2837 return false; 2838 } 2839 2840 if (!replay_can_snapshot()) { 2841 error_setg(errp, "Record/replay does not allow making snapshot " 2842 "right now. Try once more later."); 2843 return false; 2844 } 2845 2846 if (!bdrv_all_can_snapshot(has_devices, devices, errp)) { 2847 return false; 2848 } 2849 2850 /* Delete old snapshots of the same name */ 2851 if (name) { 2852 if (overwrite) { 2853 if (bdrv_all_delete_snapshot(name, has_devices, 2854 devices, errp) < 0) { 2855 return false; 2856 } 2857 } else { 2858 ret2 = bdrv_all_has_snapshot(name, has_devices, devices, errp); 2859 if (ret2 < 0) { 2860 return false; 2861 } 2862 if (ret2 == 1) { 2863 error_setg(errp, 2864 "Snapshot '%s' already exists in one or more devices", 2865 name); 2866 return false; 2867 } 2868 } 2869 } 2870 2871 bs = bdrv_all_find_vmstate_bs(vmstate, has_devices, devices, errp); 2872 if (bs == NULL) { 2873 return false; 2874 } 2875 aio_context = bdrv_get_aio_context(bs); 2876 2877 saved_vm_running = runstate_is_running(); 2878 2879 ret = global_state_store(); 2880 if (ret) { 2881 error_setg(errp, "Error saving global state"); 2882 return false; 2883 } 2884 vm_stop(RUN_STATE_SAVE_VM); 2885 2886 bdrv_drain_all_begin(); 2887 2888 aio_context_acquire(aio_context); 2889 2890 memset(sn, 0, sizeof(*sn)); 2891 2892 /* fill auxiliary fields */ 2893 sn->date_sec = g_date_time_to_unix(now); 2894 sn->date_nsec = g_date_time_get_microsecond(now) * 1000; 2895 sn->vm_clock_nsec = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 2896 if (replay_mode != REPLAY_MODE_NONE) { 2897 sn->icount = replay_get_current_icount(); 2898 } else { 2899 sn->icount = -1ULL; 2900 } 2901 2902 if (name) { 2903 pstrcpy(sn->name, sizeof(sn->name), name); 2904 } else { 2905 g_autofree char *autoname = g_date_time_format(now, "vm-%Y%m%d%H%M%S"); 2906 pstrcpy(sn->name, sizeof(sn->name), autoname); 2907 } 2908 2909 /* save the VM state */ 2910 f = qemu_fopen_bdrv(bs, 1); 2911 if (!f) { 2912 error_setg(errp, "Could not open VM state file"); 2913 goto the_end; 2914 } 2915 ret = qemu_savevm_state(f, errp); 2916 vm_state_size = qemu_file_total_transferred(f); 2917 ret2 = qemu_fclose(f); 2918 if (ret < 0) { 2919 goto the_end; 2920 } 2921 if (ret2 < 0) { 2922 ret = ret2; 2923 goto the_end; 2924 } 2925 2926 /* The bdrv_all_create_snapshot() call that follows acquires the AioContext 2927 * for itself. BDRV_POLL_WHILE() does not support nested locking because 2928 * it only releases the lock once. Therefore synchronous I/O will deadlock 2929 * unless we release the AioContext before bdrv_all_create_snapshot(). 2930 */ 2931 aio_context_release(aio_context); 2932 aio_context = NULL; 2933 2934 ret = bdrv_all_create_snapshot(sn, bs, vm_state_size, 2935 has_devices, devices, errp); 2936 if (ret < 0) { 2937 bdrv_all_delete_snapshot(sn->name, has_devices, devices, NULL); 2938 goto the_end; 2939 } 2940 2941 ret = 0; 2942 2943 the_end: 2944 if (aio_context) { 2945 aio_context_release(aio_context); 2946 } 2947 2948 bdrv_drain_all_end(); 2949 2950 if (saved_vm_running) { 2951 vm_start(); 2952 } 2953 return ret == 0; 2954 } 2955 2956 void qmp_xen_save_devices_state(const char *filename, bool has_live, bool live, 2957 Error **errp) 2958 { 2959 QEMUFile *f; 2960 QIOChannelFile *ioc; 2961 int saved_vm_running; 2962 int ret; 2963 2964 if (!has_live) { 2965 /* live default to true so old version of Xen tool stack can have a 2966 * successful live migration */ 2967 live = true; 2968 } 2969 2970 saved_vm_running = runstate_is_running(); 2971 vm_stop(RUN_STATE_SAVE_VM); 2972 global_state_store_running(); 2973 2974 ioc = qio_channel_file_new_path(filename, O_WRONLY | O_CREAT | O_TRUNC, 2975 0660, errp); 2976 if (!ioc) { 2977 goto the_end; 2978 } 2979 qio_channel_set_name(QIO_CHANNEL(ioc), "migration-xen-save-state"); 2980 f = qemu_file_new_output(QIO_CHANNEL(ioc)); 2981 object_unref(OBJECT(ioc)); 2982 ret = qemu_save_device_state(f); 2983 if (ret < 0 || qemu_fclose(f) < 0) { 2984 error_setg(errp, QERR_IO_ERROR); 2985 } else { 2986 /* libxl calls the QMP command "stop" before calling 2987 * "xen-save-devices-state" and in case of migration failure, libxl 2988 * would call "cont". 2989 * So call bdrv_inactivate_all (release locks) here to let the other 2990 * side of the migration take control of the images. 2991 */ 2992 if (live && !saved_vm_running) { 2993 ret = bdrv_inactivate_all(); 2994 if (ret) { 2995 error_setg(errp, "%s: bdrv_inactivate_all() failed (%d)", 2996 __func__, ret); 2997 } 2998 } 2999 } 3000 3001 the_end: 3002 if (saved_vm_running) { 3003 vm_start(); 3004 } 3005 } 3006 3007 void qmp_xen_load_devices_state(const char *filename, Error **errp) 3008 { 3009 QEMUFile *f; 3010 QIOChannelFile *ioc; 3011 int ret; 3012 3013 /* Guest must be paused before loading the device state; the RAM state 3014 * will already have been loaded by xc 3015 */ 3016 if (runstate_is_running()) { 3017 error_setg(errp, "Cannot update device state while vm is running"); 3018 return; 3019 } 3020 vm_stop(RUN_STATE_RESTORE_VM); 3021 3022 ioc = qio_channel_file_new_path(filename, O_RDONLY | O_BINARY, 0, errp); 3023 if (!ioc) { 3024 return; 3025 } 3026 qio_channel_set_name(QIO_CHANNEL(ioc), "migration-xen-load-state"); 3027 f = qemu_file_new_input(QIO_CHANNEL(ioc)); 3028 object_unref(OBJECT(ioc)); 3029 3030 ret = qemu_loadvm_state(f); 3031 qemu_fclose(f); 3032 if (ret < 0) { 3033 error_setg(errp, QERR_IO_ERROR); 3034 } 3035 migration_incoming_state_destroy(); 3036 } 3037 3038 bool load_snapshot(const char *name, const char *vmstate, 3039 bool has_devices, strList *devices, Error **errp) 3040 { 3041 BlockDriverState *bs_vm_state; 3042 QEMUSnapshotInfo sn; 3043 QEMUFile *f; 3044 int ret; 3045 AioContext *aio_context; 3046 MigrationIncomingState *mis = migration_incoming_get_current(); 3047 3048 if (!bdrv_all_can_snapshot(has_devices, devices, errp)) { 3049 return false; 3050 } 3051 ret = bdrv_all_has_snapshot(name, has_devices, devices, errp); 3052 if (ret < 0) { 3053 return false; 3054 } 3055 if (ret == 0) { 3056 error_setg(errp, "Snapshot '%s' does not exist in one or more devices", 3057 name); 3058 return false; 3059 } 3060 3061 bs_vm_state = bdrv_all_find_vmstate_bs(vmstate, has_devices, devices, errp); 3062 if (!bs_vm_state) { 3063 return false; 3064 } 3065 aio_context = bdrv_get_aio_context(bs_vm_state); 3066 3067 /* Don't even try to load empty VM states */ 3068 aio_context_acquire(aio_context); 3069 ret = bdrv_snapshot_find(bs_vm_state, &sn, name); 3070 aio_context_release(aio_context); 3071 if (ret < 0) { 3072 return false; 3073 } else if (sn.vm_state_size == 0) { 3074 error_setg(errp, "This is a disk-only snapshot. Revert to it " 3075 " offline using qemu-img"); 3076 return false; 3077 } 3078 3079 /* 3080 * Flush the record/replay queue. Now the VM state is going 3081 * to change. Therefore we don't need to preserve its consistency 3082 */ 3083 replay_flush_events(); 3084 3085 /* Flush all IO requests so they don't interfere with the new state. */ 3086 bdrv_drain_all_begin(); 3087 3088 ret = bdrv_all_goto_snapshot(name, has_devices, devices, errp); 3089 if (ret < 0) { 3090 goto err_drain; 3091 } 3092 3093 /* restore the VM state */ 3094 f = qemu_fopen_bdrv(bs_vm_state, 0); 3095 if (!f) { 3096 error_setg(errp, "Could not open VM state file"); 3097 goto err_drain; 3098 } 3099 3100 qemu_system_reset(SHUTDOWN_CAUSE_SNAPSHOT_LOAD); 3101 mis->from_src_file = f; 3102 3103 if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) { 3104 ret = -EINVAL; 3105 goto err_drain; 3106 } 3107 aio_context_acquire(aio_context); 3108 ret = qemu_loadvm_state(f); 3109 migration_incoming_state_destroy(); 3110 aio_context_release(aio_context); 3111 3112 bdrv_drain_all_end(); 3113 3114 if (ret < 0) { 3115 error_setg(errp, "Error %d while loading VM state", ret); 3116 return false; 3117 } 3118 3119 return true; 3120 3121 err_drain: 3122 bdrv_drain_all_end(); 3123 return false; 3124 } 3125 3126 bool delete_snapshot(const char *name, bool has_devices, 3127 strList *devices, Error **errp) 3128 { 3129 if (!bdrv_all_can_snapshot(has_devices, devices, errp)) { 3130 return false; 3131 } 3132 3133 if (bdrv_all_delete_snapshot(name, has_devices, devices, errp) < 0) { 3134 return false; 3135 } 3136 3137 return true; 3138 } 3139 3140 void vmstate_register_ram(MemoryRegion *mr, DeviceState *dev) 3141 { 3142 qemu_ram_set_idstr(mr->ram_block, 3143 memory_region_name(mr), dev); 3144 qemu_ram_set_migratable(mr->ram_block); 3145 } 3146 3147 void vmstate_unregister_ram(MemoryRegion *mr, DeviceState *dev) 3148 { 3149 qemu_ram_unset_idstr(mr->ram_block); 3150 qemu_ram_unset_migratable(mr->ram_block); 3151 } 3152 3153 void vmstate_register_ram_global(MemoryRegion *mr) 3154 { 3155 vmstate_register_ram(mr, NULL); 3156 } 3157 3158 bool vmstate_check_only_migratable(const VMStateDescription *vmsd) 3159 { 3160 /* check needed if --only-migratable is specified */ 3161 if (!only_migratable) { 3162 return true; 3163 } 3164 3165 return !(vmsd && vmsd->unmigratable); 3166 } 3167 3168 typedef struct SnapshotJob { 3169 Job common; 3170 char *tag; 3171 char *vmstate; 3172 strList *devices; 3173 Coroutine *co; 3174 Error **errp; 3175 bool ret; 3176 } SnapshotJob; 3177 3178 static void qmp_snapshot_job_free(SnapshotJob *s) 3179 { 3180 g_free(s->tag); 3181 g_free(s->vmstate); 3182 qapi_free_strList(s->devices); 3183 } 3184 3185 3186 static void snapshot_load_job_bh(void *opaque) 3187 { 3188 Job *job = opaque; 3189 SnapshotJob *s = container_of(job, SnapshotJob, common); 3190 int orig_vm_running; 3191 3192 job_progress_set_remaining(&s->common, 1); 3193 3194 orig_vm_running = runstate_is_running(); 3195 vm_stop(RUN_STATE_RESTORE_VM); 3196 3197 s->ret = load_snapshot(s->tag, s->vmstate, true, s->devices, s->errp); 3198 if (s->ret && orig_vm_running) { 3199 vm_start(); 3200 } 3201 3202 job_progress_update(&s->common, 1); 3203 3204 qmp_snapshot_job_free(s); 3205 aio_co_wake(s->co); 3206 } 3207 3208 static void snapshot_save_job_bh(void *opaque) 3209 { 3210 Job *job = opaque; 3211 SnapshotJob *s = container_of(job, SnapshotJob, common); 3212 3213 job_progress_set_remaining(&s->common, 1); 3214 s->ret = save_snapshot(s->tag, false, s->vmstate, 3215 true, s->devices, s->errp); 3216 job_progress_update(&s->common, 1); 3217 3218 qmp_snapshot_job_free(s); 3219 aio_co_wake(s->co); 3220 } 3221 3222 static void snapshot_delete_job_bh(void *opaque) 3223 { 3224 Job *job = opaque; 3225 SnapshotJob *s = container_of(job, SnapshotJob, common); 3226 3227 job_progress_set_remaining(&s->common, 1); 3228 s->ret = delete_snapshot(s->tag, true, s->devices, s->errp); 3229 job_progress_update(&s->common, 1); 3230 3231 qmp_snapshot_job_free(s); 3232 aio_co_wake(s->co); 3233 } 3234 3235 static int coroutine_fn snapshot_save_job_run(Job *job, Error **errp) 3236 { 3237 SnapshotJob *s = container_of(job, SnapshotJob, common); 3238 s->errp = errp; 3239 s->co = qemu_coroutine_self(); 3240 aio_bh_schedule_oneshot(qemu_get_aio_context(), 3241 snapshot_save_job_bh, job); 3242 qemu_coroutine_yield(); 3243 return s->ret ? 0 : -1; 3244 } 3245 3246 static int coroutine_fn snapshot_load_job_run(Job *job, Error **errp) 3247 { 3248 SnapshotJob *s = container_of(job, SnapshotJob, common); 3249 s->errp = errp; 3250 s->co = qemu_coroutine_self(); 3251 aio_bh_schedule_oneshot(qemu_get_aio_context(), 3252 snapshot_load_job_bh, job); 3253 qemu_coroutine_yield(); 3254 return s->ret ? 0 : -1; 3255 } 3256 3257 static int coroutine_fn snapshot_delete_job_run(Job *job, Error **errp) 3258 { 3259 SnapshotJob *s = container_of(job, SnapshotJob, common); 3260 s->errp = errp; 3261 s->co = qemu_coroutine_self(); 3262 aio_bh_schedule_oneshot(qemu_get_aio_context(), 3263 snapshot_delete_job_bh, job); 3264 qemu_coroutine_yield(); 3265 return s->ret ? 0 : -1; 3266 } 3267 3268 3269 static const JobDriver snapshot_load_job_driver = { 3270 .instance_size = sizeof(SnapshotJob), 3271 .job_type = JOB_TYPE_SNAPSHOT_LOAD, 3272 .run = snapshot_load_job_run, 3273 }; 3274 3275 static const JobDriver snapshot_save_job_driver = { 3276 .instance_size = sizeof(SnapshotJob), 3277 .job_type = JOB_TYPE_SNAPSHOT_SAVE, 3278 .run = snapshot_save_job_run, 3279 }; 3280 3281 static const JobDriver snapshot_delete_job_driver = { 3282 .instance_size = sizeof(SnapshotJob), 3283 .job_type = JOB_TYPE_SNAPSHOT_DELETE, 3284 .run = snapshot_delete_job_run, 3285 }; 3286 3287 3288 void qmp_snapshot_save(const char *job_id, 3289 const char *tag, 3290 const char *vmstate, 3291 strList *devices, 3292 Error **errp) 3293 { 3294 SnapshotJob *s; 3295 3296 s = job_create(job_id, &snapshot_save_job_driver, NULL, 3297 qemu_get_aio_context(), JOB_MANUAL_DISMISS, 3298 NULL, NULL, errp); 3299 if (!s) { 3300 return; 3301 } 3302 3303 s->tag = g_strdup(tag); 3304 s->vmstate = g_strdup(vmstate); 3305 s->devices = QAPI_CLONE(strList, devices); 3306 3307 job_start(&s->common); 3308 } 3309 3310 void qmp_snapshot_load(const char *job_id, 3311 const char *tag, 3312 const char *vmstate, 3313 strList *devices, 3314 Error **errp) 3315 { 3316 SnapshotJob *s; 3317 3318 s = job_create(job_id, &snapshot_load_job_driver, NULL, 3319 qemu_get_aio_context(), JOB_MANUAL_DISMISS, 3320 NULL, NULL, errp); 3321 if (!s) { 3322 return; 3323 } 3324 3325 s->tag = g_strdup(tag); 3326 s->vmstate = g_strdup(vmstate); 3327 s->devices = QAPI_CLONE(strList, devices); 3328 3329 job_start(&s->common); 3330 } 3331 3332 void qmp_snapshot_delete(const char *job_id, 3333 const char *tag, 3334 strList *devices, 3335 Error **errp) 3336 { 3337 SnapshotJob *s; 3338 3339 s = job_create(job_id, &snapshot_delete_job_driver, NULL, 3340 qemu_get_aio_context(), JOB_MANUAL_DISMISS, 3341 NULL, NULL, errp); 3342 if (!s) { 3343 return; 3344 } 3345 3346 s->tag = g_strdup(tag); 3347 s->devices = QAPI_CLONE(strList, devices); 3348 3349 job_start(&s->common); 3350 } 3351