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