1 /* 2 * Migration support for VFIO devices 3 * 4 * Copyright NVIDIA, Inc. 2020 5 * 6 * This work is licensed under the terms of the GNU GPL, version 2. See 7 * the COPYING file in the top-level directory. 8 */ 9 10 #include "qemu/osdep.h" 11 #include "qemu/main-loop.h" 12 #include "qemu/cutils.h" 13 #include "qemu/units.h" 14 #include "qemu/error-report.h" 15 #include <linux/vfio.h> 16 #include <sys/ioctl.h> 17 18 #include "sysemu/runstate.h" 19 #include "hw/vfio/vfio-common.h" 20 #include "migration/migration.h" 21 #include "migration/options.h" 22 #include "migration/savevm.h" 23 #include "migration/vmstate.h" 24 #include "migration/qemu-file.h" 25 #include "migration/register.h" 26 #include "migration/blocker.h" 27 #include "migration/misc.h" 28 #include "qapi/error.h" 29 #include "exec/ramlist.h" 30 #include "exec/ram_addr.h" 31 #include "pci.h" 32 #include "trace.h" 33 #include "hw/hw.h" 34 35 /* 36 * Flags to be used as unique delimiters for VFIO devices in the migration 37 * stream. These flags are composed as: 38 * 0xffffffff => MSB 32-bit all 1s 39 * 0xef10 => Magic ID, represents emulated (virtual) function IO 40 * 0x0000 => 16-bits reserved for flags 41 * 42 * The beginning of state information is marked by _DEV_CONFIG_STATE, 43 * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a 44 * certain state information is marked by _END_OF_STATE. 45 */ 46 #define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL) 47 #define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL) 48 #define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) 49 #define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) 50 #define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL) 51 52 /* 53 * This is an arbitrary size based on migration of mlx5 devices, where typically 54 * total device migration size is on the order of 100s of MB. Testing with 55 * larger values, e.g. 128MB and 1GB, did not show a performance improvement. 56 */ 57 #define VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE (1 * MiB) 58 59 static int64_t bytes_transferred; 60 61 static const char *mig_state_to_str(enum vfio_device_mig_state state) 62 { 63 switch (state) { 64 case VFIO_DEVICE_STATE_ERROR: 65 return "ERROR"; 66 case VFIO_DEVICE_STATE_STOP: 67 return "STOP"; 68 case VFIO_DEVICE_STATE_RUNNING: 69 return "RUNNING"; 70 case VFIO_DEVICE_STATE_STOP_COPY: 71 return "STOP_COPY"; 72 case VFIO_DEVICE_STATE_RESUMING: 73 return "RESUMING"; 74 case VFIO_DEVICE_STATE_RUNNING_P2P: 75 return "RUNNING_P2P"; 76 case VFIO_DEVICE_STATE_PRE_COPY: 77 return "PRE_COPY"; 78 case VFIO_DEVICE_STATE_PRE_COPY_P2P: 79 return "PRE_COPY_P2P"; 80 default: 81 return "UNKNOWN STATE"; 82 } 83 } 84 85 static int vfio_migration_set_state(VFIODevice *vbasedev, 86 enum vfio_device_mig_state new_state, 87 enum vfio_device_mig_state recover_state) 88 { 89 VFIOMigration *migration = vbasedev->migration; 90 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) + 91 sizeof(struct vfio_device_feature_mig_state), 92 sizeof(uint64_t))] = {}; 93 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf; 94 struct vfio_device_feature_mig_state *mig_state = 95 (struct vfio_device_feature_mig_state *)feature->data; 96 int ret; 97 98 feature->argsz = sizeof(buf); 99 feature->flags = 100 VFIO_DEVICE_FEATURE_SET | VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE; 101 mig_state->device_state = new_state; 102 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) { 103 /* Try to set the device in some good state */ 104 ret = -errno; 105 106 if (recover_state == VFIO_DEVICE_STATE_ERROR) { 107 error_report("%s: Failed setting device state to %s, err: %s. " 108 "Recover state is ERROR. Resetting device", 109 vbasedev->name, mig_state_to_str(new_state), 110 strerror(errno)); 111 112 goto reset_device; 113 } 114 115 error_report( 116 "%s: Failed setting device state to %s, err: %s. Setting device in recover state %s", 117 vbasedev->name, mig_state_to_str(new_state), 118 strerror(errno), mig_state_to_str(recover_state)); 119 120 mig_state->device_state = recover_state; 121 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) { 122 ret = -errno; 123 error_report( 124 "%s: Failed setting device in recover state, err: %s. Resetting device", 125 vbasedev->name, strerror(errno)); 126 127 goto reset_device; 128 } 129 130 migration->device_state = recover_state; 131 132 return ret; 133 } 134 135 migration->device_state = new_state; 136 if (mig_state->data_fd != -1) { 137 if (migration->data_fd != -1) { 138 /* 139 * This can happen if the device is asynchronously reset and 140 * terminates a data transfer. 141 */ 142 error_report("%s: data_fd out of sync", vbasedev->name); 143 close(mig_state->data_fd); 144 145 return -EBADF; 146 } 147 148 migration->data_fd = mig_state->data_fd; 149 } 150 151 trace_vfio_migration_set_state(vbasedev->name, mig_state_to_str(new_state)); 152 153 return 0; 154 155 reset_device: 156 if (ioctl(vbasedev->fd, VFIO_DEVICE_RESET)) { 157 hw_error("%s: Failed resetting device, err: %s", vbasedev->name, 158 strerror(errno)); 159 } 160 161 migration->device_state = VFIO_DEVICE_STATE_RUNNING; 162 163 return ret; 164 } 165 166 static int vfio_load_buffer(QEMUFile *f, VFIODevice *vbasedev, 167 uint64_t data_size) 168 { 169 VFIOMigration *migration = vbasedev->migration; 170 int ret; 171 172 ret = qemu_file_get_to_fd(f, migration->data_fd, data_size); 173 trace_vfio_load_state_device_data(vbasedev->name, data_size, ret); 174 175 return ret; 176 } 177 178 static int vfio_save_device_config_state(QEMUFile *f, void *opaque) 179 { 180 VFIODevice *vbasedev = opaque; 181 182 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE); 183 184 if (vbasedev->ops && vbasedev->ops->vfio_save_config) { 185 vbasedev->ops->vfio_save_config(vbasedev, f); 186 } 187 188 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); 189 190 trace_vfio_save_device_config_state(vbasedev->name); 191 192 return qemu_file_get_error(f); 193 } 194 195 static int vfio_load_device_config_state(QEMUFile *f, void *opaque) 196 { 197 VFIODevice *vbasedev = opaque; 198 uint64_t data; 199 200 if (vbasedev->ops && vbasedev->ops->vfio_load_config) { 201 int ret; 202 203 ret = vbasedev->ops->vfio_load_config(vbasedev, f); 204 if (ret) { 205 error_report("%s: Failed to load device config space", 206 vbasedev->name); 207 return ret; 208 } 209 } 210 211 data = qemu_get_be64(f); 212 if (data != VFIO_MIG_FLAG_END_OF_STATE) { 213 error_report("%s: Failed loading device config space, " 214 "end flag incorrect 0x%"PRIx64, vbasedev->name, data); 215 return -EINVAL; 216 } 217 218 trace_vfio_load_device_config_state(vbasedev->name); 219 return qemu_file_get_error(f); 220 } 221 222 static void vfio_migration_cleanup(VFIODevice *vbasedev) 223 { 224 VFIOMigration *migration = vbasedev->migration; 225 226 close(migration->data_fd); 227 migration->data_fd = -1; 228 } 229 230 static int vfio_query_stop_copy_size(VFIODevice *vbasedev, 231 uint64_t *stop_copy_size) 232 { 233 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) + 234 sizeof(struct vfio_device_feature_mig_data_size), 235 sizeof(uint64_t))] = {}; 236 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf; 237 struct vfio_device_feature_mig_data_size *mig_data_size = 238 (struct vfio_device_feature_mig_data_size *)feature->data; 239 240 feature->argsz = sizeof(buf); 241 feature->flags = 242 VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIG_DATA_SIZE; 243 244 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) { 245 return -errno; 246 } 247 248 *stop_copy_size = mig_data_size->stop_copy_length; 249 250 return 0; 251 } 252 253 static int vfio_query_precopy_size(VFIOMigration *migration) 254 { 255 struct vfio_precopy_info precopy = { 256 .argsz = sizeof(precopy), 257 }; 258 259 migration->precopy_init_size = 0; 260 migration->precopy_dirty_size = 0; 261 262 if (ioctl(migration->data_fd, VFIO_MIG_GET_PRECOPY_INFO, &precopy)) { 263 return -errno; 264 } 265 266 migration->precopy_init_size = precopy.initial_bytes; 267 migration->precopy_dirty_size = precopy.dirty_bytes; 268 269 return 0; 270 } 271 272 /* Returns the size of saved data on success and -errno on error */ 273 static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration) 274 { 275 ssize_t data_size; 276 277 data_size = read(migration->data_fd, migration->data_buffer, 278 migration->data_buffer_size); 279 if (data_size < 0) { 280 /* 281 * Pre-copy emptied all the device state for now. For more information, 282 * please refer to the Linux kernel VFIO uAPI. 283 */ 284 if (errno == ENOMSG) { 285 return 0; 286 } 287 288 return -errno; 289 } 290 if (data_size == 0) { 291 return 0; 292 } 293 294 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); 295 qemu_put_be64(f, data_size); 296 qemu_put_buffer(f, migration->data_buffer, data_size); 297 bytes_transferred += data_size; 298 299 trace_vfio_save_block(migration->vbasedev->name, data_size); 300 301 return qemu_file_get_error(f) ?: data_size; 302 } 303 304 static void vfio_update_estimated_pending_data(VFIOMigration *migration, 305 uint64_t data_size) 306 { 307 if (!data_size) { 308 /* 309 * Pre-copy emptied all the device state for now, update estimated sizes 310 * accordingly. 311 */ 312 migration->precopy_init_size = 0; 313 migration->precopy_dirty_size = 0; 314 315 return; 316 } 317 318 if (migration->precopy_init_size) { 319 uint64_t init_size = MIN(migration->precopy_init_size, data_size); 320 321 migration->precopy_init_size -= init_size; 322 data_size -= init_size; 323 } 324 325 migration->precopy_dirty_size -= MIN(migration->precopy_dirty_size, 326 data_size); 327 } 328 329 static bool vfio_precopy_supported(VFIODevice *vbasedev) 330 { 331 VFIOMigration *migration = vbasedev->migration; 332 333 return migration->mig_flags & VFIO_MIGRATION_PRE_COPY; 334 } 335 336 /* ---------------------------------------------------------------------- */ 337 338 static int vfio_save_setup(QEMUFile *f, void *opaque) 339 { 340 VFIODevice *vbasedev = opaque; 341 VFIOMigration *migration = vbasedev->migration; 342 uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE; 343 344 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE); 345 346 vfio_query_stop_copy_size(vbasedev, &stop_copy_size); 347 migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE, 348 stop_copy_size); 349 migration->data_buffer = g_try_malloc0(migration->data_buffer_size); 350 if (!migration->data_buffer) { 351 error_report("%s: Failed to allocate migration data buffer", 352 vbasedev->name); 353 return -ENOMEM; 354 } 355 356 if (vfio_precopy_supported(vbasedev)) { 357 int ret; 358 359 switch (migration->device_state) { 360 case VFIO_DEVICE_STATE_RUNNING: 361 ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_PRE_COPY, 362 VFIO_DEVICE_STATE_RUNNING); 363 if (ret) { 364 return ret; 365 } 366 367 vfio_query_precopy_size(migration); 368 369 break; 370 case VFIO_DEVICE_STATE_STOP: 371 /* vfio_save_complete_precopy() will go to STOP_COPY */ 372 break; 373 default: 374 return -EINVAL; 375 } 376 } 377 378 trace_vfio_save_setup(vbasedev->name, migration->data_buffer_size); 379 380 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); 381 382 return qemu_file_get_error(f); 383 } 384 385 static void vfio_save_cleanup(void *opaque) 386 { 387 VFIODevice *vbasedev = opaque; 388 VFIOMigration *migration = vbasedev->migration; 389 390 /* 391 * Changing device state from STOP_COPY to STOP can take time. Do it here, 392 * after migration has completed, so it won't increase downtime. 393 */ 394 if (migration->device_state == VFIO_DEVICE_STATE_STOP_COPY) { 395 /* 396 * If setting the device in STOP state fails, the device should be 397 * reset. To do so, use ERROR state as a recover state. 398 */ 399 vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP, 400 VFIO_DEVICE_STATE_ERROR); 401 } 402 403 g_free(migration->data_buffer); 404 migration->data_buffer = NULL; 405 migration->precopy_init_size = 0; 406 migration->precopy_dirty_size = 0; 407 migration->initial_data_sent = false; 408 vfio_migration_cleanup(vbasedev); 409 trace_vfio_save_cleanup(vbasedev->name); 410 } 411 412 static void vfio_state_pending_estimate(void *opaque, uint64_t *must_precopy, 413 uint64_t *can_postcopy) 414 { 415 VFIODevice *vbasedev = opaque; 416 VFIOMigration *migration = vbasedev->migration; 417 418 if (!vfio_device_state_is_precopy(vbasedev)) { 419 return; 420 } 421 422 *must_precopy += 423 migration->precopy_init_size + migration->precopy_dirty_size; 424 425 trace_vfio_state_pending_estimate(vbasedev->name, *must_precopy, 426 *can_postcopy, 427 migration->precopy_init_size, 428 migration->precopy_dirty_size); 429 } 430 431 /* 432 * Migration size of VFIO devices can be as little as a few KBs or as big as 433 * many GBs. This value should be big enough to cover the worst case. 434 */ 435 #define VFIO_MIG_STOP_COPY_SIZE (100 * GiB) 436 437 static void vfio_state_pending_exact(void *opaque, uint64_t *must_precopy, 438 uint64_t *can_postcopy) 439 { 440 VFIODevice *vbasedev = opaque; 441 VFIOMigration *migration = vbasedev->migration; 442 uint64_t stop_copy_size = VFIO_MIG_STOP_COPY_SIZE; 443 444 /* 445 * If getting pending migration size fails, VFIO_MIG_STOP_COPY_SIZE is 446 * reported so downtime limit won't be violated. 447 */ 448 vfio_query_stop_copy_size(vbasedev, &stop_copy_size); 449 *must_precopy += stop_copy_size; 450 451 if (vfio_device_state_is_precopy(vbasedev)) { 452 vfio_query_precopy_size(migration); 453 454 *must_precopy += 455 migration->precopy_init_size + migration->precopy_dirty_size; 456 } 457 458 trace_vfio_state_pending_exact(vbasedev->name, *must_precopy, *can_postcopy, 459 stop_copy_size, migration->precopy_init_size, 460 migration->precopy_dirty_size); 461 } 462 463 static bool vfio_is_active_iterate(void *opaque) 464 { 465 VFIODevice *vbasedev = opaque; 466 467 return vfio_device_state_is_precopy(vbasedev); 468 } 469 470 static int vfio_save_iterate(QEMUFile *f, void *opaque) 471 { 472 VFIODevice *vbasedev = opaque; 473 VFIOMigration *migration = vbasedev->migration; 474 ssize_t data_size; 475 476 data_size = vfio_save_block(f, migration); 477 if (data_size < 0) { 478 return data_size; 479 } 480 481 vfio_update_estimated_pending_data(migration, data_size); 482 483 if (migrate_switchover_ack() && !migration->precopy_init_size && 484 !migration->initial_data_sent) { 485 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_INIT_DATA_SENT); 486 migration->initial_data_sent = true; 487 } else { 488 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); 489 } 490 491 trace_vfio_save_iterate(vbasedev->name, migration->precopy_init_size, 492 migration->precopy_dirty_size); 493 494 /* 495 * A VFIO device's pre-copy dirty_bytes is not guaranteed to reach zero. 496 * Return 1 so following handlers will not be potentially blocked. 497 */ 498 return 1; 499 } 500 501 static int vfio_save_complete_precopy(QEMUFile *f, void *opaque) 502 { 503 VFIODevice *vbasedev = opaque; 504 ssize_t data_size; 505 int ret; 506 507 /* We reach here with device state STOP or STOP_COPY only */ 508 ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY, 509 VFIO_DEVICE_STATE_STOP); 510 if (ret) { 511 return ret; 512 } 513 514 do { 515 data_size = vfio_save_block(f, vbasedev->migration); 516 if (data_size < 0) { 517 return data_size; 518 } 519 } while (data_size); 520 521 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); 522 ret = qemu_file_get_error(f); 523 if (ret) { 524 return ret; 525 } 526 527 trace_vfio_save_complete_precopy(vbasedev->name, ret); 528 529 return ret; 530 } 531 532 static void vfio_save_state(QEMUFile *f, void *opaque) 533 { 534 VFIODevice *vbasedev = opaque; 535 int ret; 536 537 ret = vfio_save_device_config_state(f, opaque); 538 if (ret) { 539 error_report("%s: Failed to save device config space", 540 vbasedev->name); 541 qemu_file_set_error(f, ret); 542 } 543 } 544 545 static int vfio_load_setup(QEMUFile *f, void *opaque) 546 { 547 VFIODevice *vbasedev = opaque; 548 549 return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING, 550 vbasedev->migration->device_state); 551 } 552 553 static int vfio_load_cleanup(void *opaque) 554 { 555 VFIODevice *vbasedev = opaque; 556 557 vfio_migration_cleanup(vbasedev); 558 trace_vfio_load_cleanup(vbasedev->name); 559 560 return 0; 561 } 562 563 static int vfio_load_state(QEMUFile *f, void *opaque, int version_id) 564 { 565 VFIODevice *vbasedev = opaque; 566 int ret = 0; 567 uint64_t data; 568 569 data = qemu_get_be64(f); 570 while (data != VFIO_MIG_FLAG_END_OF_STATE) { 571 572 trace_vfio_load_state(vbasedev->name, data); 573 574 switch (data) { 575 case VFIO_MIG_FLAG_DEV_CONFIG_STATE: 576 { 577 return vfio_load_device_config_state(f, opaque); 578 } 579 case VFIO_MIG_FLAG_DEV_SETUP_STATE: 580 { 581 data = qemu_get_be64(f); 582 if (data == VFIO_MIG_FLAG_END_OF_STATE) { 583 return ret; 584 } else { 585 error_report("%s: SETUP STATE: EOS not found 0x%"PRIx64, 586 vbasedev->name, data); 587 return -EINVAL; 588 } 589 break; 590 } 591 case VFIO_MIG_FLAG_DEV_DATA_STATE: 592 { 593 uint64_t data_size = qemu_get_be64(f); 594 595 if (data_size) { 596 ret = vfio_load_buffer(f, vbasedev, data_size); 597 if (ret < 0) { 598 return ret; 599 } 600 } 601 break; 602 } 603 case VFIO_MIG_FLAG_DEV_INIT_DATA_SENT: 604 { 605 if (!vfio_precopy_supported(vbasedev) || 606 !migrate_switchover_ack()) { 607 error_report("%s: Received INIT_DATA_SENT but switchover ack " 608 "is not used", vbasedev->name); 609 return -EINVAL; 610 } 611 612 ret = qemu_loadvm_approve_switchover(); 613 if (ret) { 614 error_report( 615 "%s: qemu_loadvm_approve_switchover failed, err=%d (%s)", 616 vbasedev->name, ret, strerror(-ret)); 617 } 618 619 return ret; 620 } 621 default: 622 error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data); 623 return -EINVAL; 624 } 625 626 data = qemu_get_be64(f); 627 ret = qemu_file_get_error(f); 628 if (ret) { 629 return ret; 630 } 631 } 632 return ret; 633 } 634 635 static bool vfio_switchover_ack_needed(void *opaque) 636 { 637 VFIODevice *vbasedev = opaque; 638 639 return vfio_precopy_supported(vbasedev); 640 } 641 642 static const SaveVMHandlers savevm_vfio_handlers = { 643 .save_setup = vfio_save_setup, 644 .save_cleanup = vfio_save_cleanup, 645 .state_pending_estimate = vfio_state_pending_estimate, 646 .state_pending_exact = vfio_state_pending_exact, 647 .is_active_iterate = vfio_is_active_iterate, 648 .save_live_iterate = vfio_save_iterate, 649 .save_live_complete_precopy = vfio_save_complete_precopy, 650 .save_state = vfio_save_state, 651 .load_setup = vfio_load_setup, 652 .load_cleanup = vfio_load_cleanup, 653 .load_state = vfio_load_state, 654 .switchover_ack_needed = vfio_switchover_ack_needed, 655 }; 656 657 /* ---------------------------------------------------------------------- */ 658 659 static void vfio_vmstate_change_prepare(void *opaque, bool running, 660 RunState state) 661 { 662 VFIODevice *vbasedev = opaque; 663 VFIOMigration *migration = vbasedev->migration; 664 enum vfio_device_mig_state new_state; 665 int ret; 666 667 new_state = migration->device_state == VFIO_DEVICE_STATE_PRE_COPY ? 668 VFIO_DEVICE_STATE_PRE_COPY_P2P : 669 VFIO_DEVICE_STATE_RUNNING_P2P; 670 671 /* 672 * If setting the device in new_state fails, the device should be reset. 673 * To do so, use ERROR state as a recover state. 674 */ 675 ret = vfio_migration_set_state(vbasedev, new_state, 676 VFIO_DEVICE_STATE_ERROR); 677 if (ret) { 678 /* 679 * Migration should be aborted in this case, but vm_state_notify() 680 * currently does not support reporting failures. 681 */ 682 if (migrate_get_current()->to_dst_file) { 683 qemu_file_set_error(migrate_get_current()->to_dst_file, ret); 684 } 685 } 686 687 trace_vfio_vmstate_change_prepare(vbasedev->name, running, 688 RunState_str(state), 689 mig_state_to_str(new_state)); 690 } 691 692 static void vfio_vmstate_change(void *opaque, bool running, RunState state) 693 { 694 VFIODevice *vbasedev = opaque; 695 enum vfio_device_mig_state new_state; 696 int ret; 697 698 if (running) { 699 new_state = VFIO_DEVICE_STATE_RUNNING; 700 } else { 701 new_state = 702 (vfio_device_state_is_precopy(vbasedev) && 703 (state == RUN_STATE_FINISH_MIGRATE || state == RUN_STATE_PAUSED)) ? 704 VFIO_DEVICE_STATE_STOP_COPY : 705 VFIO_DEVICE_STATE_STOP; 706 } 707 708 /* 709 * If setting the device in new_state fails, the device should be reset. 710 * To do so, use ERROR state as a recover state. 711 */ 712 ret = vfio_migration_set_state(vbasedev, new_state, 713 VFIO_DEVICE_STATE_ERROR); 714 if (ret) { 715 /* 716 * Migration should be aborted in this case, but vm_state_notify() 717 * currently does not support reporting failures. 718 */ 719 if (migrate_get_current()->to_dst_file) { 720 qemu_file_set_error(migrate_get_current()->to_dst_file, ret); 721 } 722 } 723 724 trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state), 725 mig_state_to_str(new_state)); 726 } 727 728 static void vfio_migration_state_notifier(Notifier *notifier, void *data) 729 { 730 MigrationState *s = data; 731 VFIOMigration *migration = container_of(notifier, VFIOMigration, 732 migration_state); 733 VFIODevice *vbasedev = migration->vbasedev; 734 735 trace_vfio_migration_state_notifier(vbasedev->name, 736 MigrationStatus_str(s->state)); 737 738 switch (s->state) { 739 case MIGRATION_STATUS_CANCELLING: 740 case MIGRATION_STATUS_CANCELLED: 741 case MIGRATION_STATUS_FAILED: 742 /* 743 * If setting the device in RUNNING state fails, the device should 744 * be reset. To do so, use ERROR state as a recover state. 745 */ 746 vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RUNNING, 747 VFIO_DEVICE_STATE_ERROR); 748 } 749 } 750 751 static void vfio_migration_free(VFIODevice *vbasedev) 752 { 753 g_free(vbasedev->migration); 754 vbasedev->migration = NULL; 755 } 756 757 static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags) 758 { 759 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) + 760 sizeof(struct vfio_device_feature_migration), 761 sizeof(uint64_t))] = {}; 762 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf; 763 struct vfio_device_feature_migration *mig = 764 (struct vfio_device_feature_migration *)feature->data; 765 766 feature->argsz = sizeof(buf); 767 feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION; 768 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) { 769 return -errno; 770 } 771 772 *mig_flags = mig->flags; 773 774 return 0; 775 } 776 777 static bool vfio_dma_logging_supported(VFIODevice *vbasedev) 778 { 779 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature), 780 sizeof(uint64_t))] = {}; 781 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf; 782 783 feature->argsz = sizeof(buf); 784 feature->flags = VFIO_DEVICE_FEATURE_PROBE | 785 VFIO_DEVICE_FEATURE_DMA_LOGGING_START; 786 787 return !ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature); 788 } 789 790 static int vfio_migration_init(VFIODevice *vbasedev) 791 { 792 int ret; 793 Object *obj; 794 VFIOMigration *migration; 795 char id[256] = ""; 796 g_autofree char *path = NULL, *oid = NULL; 797 uint64_t mig_flags = 0; 798 VMChangeStateHandler *prepare_cb; 799 800 if (!vbasedev->ops->vfio_get_object) { 801 return -EINVAL; 802 } 803 804 obj = vbasedev->ops->vfio_get_object(vbasedev); 805 if (!obj) { 806 return -EINVAL; 807 } 808 809 ret = vfio_migration_query_flags(vbasedev, &mig_flags); 810 if (ret) { 811 return ret; 812 } 813 814 /* Basic migration functionality must be supported */ 815 if (!(mig_flags & VFIO_MIGRATION_STOP_COPY)) { 816 return -EOPNOTSUPP; 817 } 818 819 vbasedev->migration = g_new0(VFIOMigration, 1); 820 migration = vbasedev->migration; 821 migration->vbasedev = vbasedev; 822 migration->device_state = VFIO_DEVICE_STATE_RUNNING; 823 migration->data_fd = -1; 824 migration->mig_flags = mig_flags; 825 826 vbasedev->dirty_pages_supported = vfio_dma_logging_supported(vbasedev); 827 828 oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj))); 829 if (oid) { 830 path = g_strdup_printf("%s/vfio", oid); 831 } else { 832 path = g_strdup("vfio"); 833 } 834 strpadcpy(id, sizeof(id), path, '\0'); 835 836 register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers, 837 vbasedev); 838 839 prepare_cb = migration->mig_flags & VFIO_MIGRATION_P2P ? 840 vfio_vmstate_change_prepare : 841 NULL; 842 migration->vm_state = qdev_add_vm_change_state_handler_full( 843 vbasedev->dev, vfio_vmstate_change, prepare_cb, vbasedev); 844 migration->migration_state.notify = vfio_migration_state_notifier; 845 add_migration_state_change_notifier(&migration->migration_state); 846 847 return 0; 848 } 849 850 static void vfio_migration_deinit(VFIODevice *vbasedev) 851 { 852 VFIOMigration *migration = vbasedev->migration; 853 854 remove_migration_state_change_notifier(&migration->migration_state); 855 qemu_del_vm_change_state_handler(migration->vm_state); 856 unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev); 857 vfio_migration_free(vbasedev); 858 vfio_unblock_multiple_devices_migration(); 859 } 860 861 static int vfio_block_migration(VFIODevice *vbasedev, Error *err, Error **errp) 862 { 863 int ret; 864 865 if (vbasedev->enable_migration == ON_OFF_AUTO_ON) { 866 error_propagate(errp, err); 867 return -EINVAL; 868 } 869 870 vbasedev->migration_blocker = error_copy(err); 871 error_free(err); 872 873 ret = migrate_add_blocker(vbasedev->migration_blocker, errp); 874 if (ret < 0) { 875 error_free(vbasedev->migration_blocker); 876 vbasedev->migration_blocker = NULL; 877 } 878 879 return ret; 880 } 881 882 /* ---------------------------------------------------------------------- */ 883 884 int64_t vfio_mig_bytes_transferred(void) 885 { 886 return bytes_transferred; 887 } 888 889 void vfio_reset_bytes_transferred(void) 890 { 891 bytes_transferred = 0; 892 } 893 894 /* 895 * Return true when either migration initialized or blocker registered. 896 * Currently only return false when adding blocker fails which will 897 * de-register vfio device. 898 */ 899 bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp) 900 { 901 Error *err = NULL; 902 int ret; 903 904 if (vbasedev->enable_migration == ON_OFF_AUTO_OFF) { 905 error_setg(&err, "%s: Migration is disabled for VFIO device", 906 vbasedev->name); 907 return !vfio_block_migration(vbasedev, err, errp); 908 } 909 910 ret = vfio_migration_init(vbasedev); 911 if (ret) { 912 if (ret == -ENOTTY) { 913 error_setg(&err, "%s: VFIO migration is not supported in kernel", 914 vbasedev->name); 915 } else { 916 error_setg(&err, 917 "%s: Migration couldn't be initialized for VFIO device, " 918 "err: %d (%s)", 919 vbasedev->name, ret, strerror(-ret)); 920 } 921 922 return !vfio_block_migration(vbasedev, err, errp); 923 } 924 925 if (!vbasedev->dirty_pages_supported) { 926 if (vbasedev->enable_migration == ON_OFF_AUTO_AUTO) { 927 error_setg(&err, 928 "%s: VFIO device doesn't support device dirty tracking", 929 vbasedev->name); 930 goto add_blocker; 931 } 932 933 warn_report("%s: VFIO device doesn't support device dirty tracking", 934 vbasedev->name); 935 } 936 937 ret = vfio_block_multiple_devices_migration(vbasedev, errp); 938 if (ret) { 939 goto out_deinit; 940 } 941 942 if (vfio_viommu_preset(vbasedev)) { 943 error_setg(&err, "%s: Migration is currently not supported " 944 "with vIOMMU enabled", vbasedev->name); 945 goto add_blocker; 946 } 947 948 trace_vfio_migration_realize(vbasedev->name); 949 return true; 950 951 add_blocker: 952 ret = vfio_block_migration(vbasedev, err, errp); 953 out_deinit: 954 if (ret) { 955 vfio_migration_deinit(vbasedev); 956 } 957 return !ret; 958 } 959 960 void vfio_migration_exit(VFIODevice *vbasedev) 961 { 962 if (vbasedev->migration) { 963 vfio_migration_deinit(vbasedev); 964 } 965 966 if (vbasedev->migration_blocker) { 967 migrate_del_blocker(vbasedev->migration_blocker); 968 error_free(vbasedev->migration_blocker); 969 vbasedev->migration_blocker = NULL; 970 } 971 } 972