hw/vfio/migration.c

   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 <linux/vfio.h>
  14 #include <sys/ioctl.h>
  15
  16 #include "sysemu/runstate.h"
  17 #include "hw/vfio/vfio-common.h"
  18 #include "migration/migration.h"
  19 #include "migration/vmstate.h"
  20 #include "migration/qemu-file.h"
  21 #include "migration/register.h"
  22 #include "migration/blocker.h"
  23 #include "migration/misc.h"
  24 #include "qapi/error.h"
  25 #include "exec/ramlist.h"
  26 #include "exec/ram_addr.h"
  27 #include "pci.h"
  28 #include "trace.h"
  29 #include "hw/hw.h"
  30
  31 /*
  32  * Flags to be used as unique delimiters for VFIO devices in the migration
  33  * stream. These flags are composed as:
  34  * 0xffffffff => MSB 32-bit all 1s
  35  * 0xef10     => Magic ID, represents emulated (virtual) function IO
  36  * 0x0000     => 16-bits reserved for flags
  37  *
  38  * The beginning of state information is marked by _DEV_CONFIG_STATE,
  39  * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a
  40  * certain state information is marked by _END_OF_STATE.
  41  */
  42 #define VFIO_MIG_FLAG_END_OF_STATE      (0xffffffffef100001ULL)
  43 #define VFIO_MIG_FLAG_DEV_CONFIG_STATE  (0xffffffffef100002ULL)
  44 #define VFIO_MIG_FLAG_DEV_SETUP_STATE   (0xffffffffef100003ULL)
  45 #define VFIO_MIG_FLAG_DEV_DATA_STATE    (0xffffffffef100004ULL)
  46
  47 static int64_t bytes_transferred;
  48
  49 static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count,
  50                                   off_t off, bool iswrite)
  51 {
  52     int ret;
  53
  54     ret = iswrite ? pwrite(vbasedev->fd, val, count, off) :
  55                     pread(vbasedev->fd, val, count, off);
  56     if (ret < count) {
  57         error_report("vfio_mig_%s %d byte %s: failed at offset 0x%"
  58                      HWADDR_PRIx", err: %s", iswrite ? "write" : "read", count,
  59                      vbasedev->name, off, strerror(errno));
  60         return (ret < 0) ? ret : -EINVAL;
  61     }
  62     return 0;
  63 }
  64
  65 static int vfio_mig_rw(VFIODevice *vbasedev, __u8 *buf, size_t count,
  66                        off_t off, bool iswrite)
  67 {
  68     int ret, done = 0;
  69     __u8 *tbuf = buf;
  70
  71     while (count) {
  72         int bytes = 0;
  73
  74         if (count >= 8 && !(off % 8)) {
  75             bytes = 8;
  76         } else if (count >= 4 && !(off % 4)) {
  77             bytes = 4;
  78         } else if (count >= 2 && !(off % 2)) {
  79             bytes = 2;
  80         } else {
  81             bytes = 1;
  82         }
  83
  84         ret = vfio_mig_access(vbasedev, tbuf, bytes, off, iswrite);
  85         if (ret) {
  86             return ret;
  87         }
  88
  89         count -= bytes;
  90         done += bytes;
  91         off += bytes;
  92         tbuf += bytes;
  93     }
  94     return done;
  95 }
  96
  97 #define vfio_mig_read(f, v, c, o)       vfio_mig_rw(f, (__u8 *)v, c, o, false)
  98 #define vfio_mig_write(f, v, c, o)      vfio_mig_rw(f, (__u8 *)v, c, o, true)
  99
 100 #define VFIO_MIG_STRUCT_OFFSET(f)       \
 101                                  offsetof(struct vfio_device_migration_info, f)
 102 /*
 103  * Change the device_state register for device @vbasedev. Bits set in @mask
 104  * are preserved, bits set in @value are set, and bits not set in either @mask
 105  * or @value are cleared in device_state. If the register cannot be accessed,
 106  * the resulting state would be invalid, or the device enters an error state,
 107  * an error is returned.
 108  */
 109
 110 static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask,
 111                                     uint32_t value)
 112 {
 113     VFIOMigration *migration = vbasedev->migration;
 114     VFIORegion *region = &migration->region;
 115     off_t dev_state_off = region->fd_offset +
 116                           VFIO_MIG_STRUCT_OFFSET(device_state);
 117     uint32_t device_state;
 118     int ret;
 119
 120     ret = vfio_mig_read(vbasedev, &device_state, sizeof(device_state),
 121                         dev_state_off);
 122     if (ret < 0) {
 123         return ret;
 124     }
 125
 126     device_state = (device_state & mask) | value;
 127
 128     if (!VFIO_DEVICE_STATE_VALID(device_state)) {
 129         return -EINVAL;
 130     }
 131
 132     ret = vfio_mig_write(vbasedev, &device_state, sizeof(device_state),
 133                          dev_state_off);
 134     if (ret < 0) {
 135         int rret;
 136
 137         rret = vfio_mig_read(vbasedev, &device_state, sizeof(device_state),
 138                              dev_state_off);
 139
 140         if ((rret < 0) || (VFIO_DEVICE_STATE_IS_ERROR(device_state))) {
 141             hw_error("%s: Device in error state 0x%x", vbasedev->name,
 142                      device_state);
 143             return rret ? rret : -EIO;
 144         }
 145         return ret;
 146     }
 147
 148     migration->device_state = device_state;
 149     trace_vfio_migration_set_state(vbasedev->name, device_state);
 150     return 0;
 151 }
 152
 153 static void *get_data_section_size(VFIORegion *region, uint64_t data_offset,
 154                                    uint64_t data_size, uint64_t *size)
 155 {
 156     void *ptr = NULL;
 157     uint64_t limit = 0;
 158     int i;
 159
 160     if (!region->mmaps) {
 161         if (size) {
 162             *size = MIN(data_size, region->size - data_offset);
 163         }
 164         return ptr;
 165     }
 166
 167     for (i = 0; i < region->nr_mmaps; i++) {
 168         VFIOMmap *map = region->mmaps + i;
 169
 170         if ((data_offset >= map->offset) &&
 171             (data_offset < map->offset + map->size)) {
 172
 173             /* check if data_offset is within sparse mmap areas */
 174             ptr = map->mmap + data_offset - map->offset;
 175             if (size) {
 176                 *size = MIN(data_size, map->offset + map->size - data_offset);
 177             }
 178             break;
 179         } else if ((data_offset < map->offset) &&
 180                    (!limit || limit > map->offset)) {
 181             /*
 182              * data_offset is not within sparse mmap areas, find size of
 183              * non-mapped area. Check through all list since region->mmaps list
 184              * is not sorted.
 185              */
 186             limit = map->offset;
 187         }
 188     }
 189
 190     if (!ptr && size) {
 191         *size = limit ? MIN(data_size, limit - data_offset) : data_size;
 192     }
 193     return ptr;
 194 }
 195
 196 static int vfio_save_buffer(QEMUFile *f, VFIODevice *vbasedev, uint64_t *size)
 197 {
 198     VFIOMigration *migration = vbasedev->migration;
 199     VFIORegion *region = &migration->region;
 200     uint64_t data_offset = 0, data_size = 0, sz;
 201     int ret;
 202
 203     ret = vfio_mig_read(vbasedev, &data_offset, sizeof(data_offset),
 204                       region->fd_offset + VFIO_MIG_STRUCT_OFFSET(data_offset));
 205     if (ret < 0) {
 206         return ret;
 207     }
 208
 209     ret = vfio_mig_read(vbasedev, &data_size, sizeof(data_size),
 210                         region->fd_offset + VFIO_MIG_STRUCT_OFFSET(data_size));
 211     if (ret < 0) {
 212         return ret;
 213     }
 214
 215     trace_vfio_save_buffer(vbasedev->name, data_offset, data_size,
 216                            migration->pending_bytes);
 217
 218     qemu_put_be64(f, data_size);
 219     sz = data_size;
 220
 221     while (sz) {
 222         void *buf;
 223         uint64_t sec_size;
 224         bool buf_allocated = false;
 225
 226         buf = get_data_section_size(region, data_offset, sz, &sec_size);
 227
 228         if (!buf) {
 229             buf = g_try_malloc(sec_size);
 230             if (!buf) {
 231                 error_report("%s: Error allocating buffer ", __func__);
 232                 return -ENOMEM;
 233             }
 234             buf_allocated = true;
 235
 236             ret = vfio_mig_read(vbasedev, buf, sec_size,
 237                                 region->fd_offset + data_offset);
 238             if (ret < 0) {
 239                 g_free(buf);
 240                 return ret;
 241             }
 242         }
 243
 244         qemu_put_buffer(f, buf, sec_size);
 245
 246         if (buf_allocated) {
 247             g_free(buf);
 248         }
 249         sz -= sec_size;
 250         data_offset += sec_size;
 251     }
 252
 253     ret = qemu_file_get_error(f);
 254
 255     if (!ret && size) {
 256         *size = data_size;
 257     }
 258
 259     bytes_transferred += data_size;
 260     return ret;
 261 }
 262
 263 static int vfio_load_buffer(QEMUFile *f, VFIODevice *vbasedev,
 264                             uint64_t data_size)
 265 {
 266     VFIORegion *region = &vbasedev->migration->region;
 267     uint64_t data_offset = 0, size, report_size;
 268     int ret;
 269
 270     do {
 271         ret = vfio_mig_read(vbasedev, &data_offset, sizeof(data_offset),
 272                       region->fd_offset + VFIO_MIG_STRUCT_OFFSET(data_offset));
 273         if (ret < 0) {
 274             return ret;
 275         }
 276
 277         if (data_offset + data_size > region->size) {
 278             /*
 279              * If data_size is greater than the data section of migration region
 280              * then iterate the write buffer operation. This case can occur if
 281              * size of migration region at destination is smaller than size of
 282              * migration region at source.
 283              */
 284             report_size = size = region->size - data_offset;
 285             data_size -= size;
 286         } else {
 287             report_size = size = data_size;
 288             data_size = 0;
 289         }
 290
 291         trace_vfio_load_state_device_data(vbasedev->name, data_offset, size);
 292
 293         while (size) {
 294             void *buf;
 295             uint64_t sec_size;
 296             bool buf_alloc = false;
 297
 298             buf = get_data_section_size(region, data_offset, size, &sec_size);
 299
 300             if (!buf) {
 301                 buf = g_try_malloc(sec_size);
 302                 if (!buf) {
 303                     error_report("%s: Error allocating buffer ", __func__);
 304                     return -ENOMEM;
 305                 }
 306                 buf_alloc = true;
 307             }
 308
 309             qemu_get_buffer(f, buf, sec_size);
 310
 311             if (buf_alloc) {
 312                 ret = vfio_mig_write(vbasedev, buf, sec_size,
 313                         region->fd_offset + data_offset);
 314                 g_free(buf);
 315
 316                 if (ret < 0) {
 317                     return ret;
 318                 }
 319             }
 320             size -= sec_size;
 321             data_offset += sec_size;
 322         }
 323
 324         ret = vfio_mig_write(vbasedev, &report_size, sizeof(report_size),
 325                         region->fd_offset + VFIO_MIG_STRUCT_OFFSET(data_size));
 326         if (ret < 0) {
 327             return ret;
 328         }
 329     } while (data_size);
 330
 331     return 0;
 332 }
 333
 334 static int vfio_update_pending(VFIODevice *vbasedev)
 335 {
 336     VFIOMigration *migration = vbasedev->migration;
 337     VFIORegion *region = &migration->region;
 338     uint64_t pending_bytes = 0;
 339     int ret;
 340
 341     ret = vfio_mig_read(vbasedev, &pending_bytes, sizeof(pending_bytes),
 342                     region->fd_offset + VFIO_MIG_STRUCT_OFFSET(pending_bytes));
 343     if (ret < 0) {
 344         migration->pending_bytes = 0;
 345         return ret;
 346     }
 347
 348     migration->pending_bytes = pending_bytes;
 349     trace_vfio_update_pending(vbasedev->name, pending_bytes);
 350     return 0;
 351 }
 352
 353 static int vfio_save_device_config_state(QEMUFile *f, void *opaque)
 354 {
 355     VFIODevice *vbasedev = opaque;
 356
 357     qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE);
 358
 359     if (vbasedev->ops && vbasedev->ops->vfio_save_config) {
 360         vbasedev->ops->vfio_save_config(vbasedev, f);
 361     }
 362
 363     qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
 364
 365     trace_vfio_save_device_config_state(vbasedev->name);
 366
 367     return qemu_file_get_error(f);
 368 }
 369
 370 static int vfio_load_device_config_state(QEMUFile *f, void *opaque)
 371 {
 372     VFIODevice *vbasedev = opaque;
 373     uint64_t data;
 374
 375     if (vbasedev->ops && vbasedev->ops->vfio_load_config) {
 376         int ret;
 377
 378         ret = vbasedev->ops->vfio_load_config(vbasedev, f);
 379         if (ret) {
 380             error_report("%s: Failed to load device config space",
 381                          vbasedev->name);
 382             return ret;
 383         }
 384     }
 385
 386     data = qemu_get_be64(f);
 387     if (data != VFIO_MIG_FLAG_END_OF_STATE) {
 388         error_report("%s: Failed loading device config space, "
 389                      "end flag incorrect 0x%"PRIx64, vbasedev->name, data);
 390         return -EINVAL;
 391     }
 392
 393     trace_vfio_load_device_config_state(vbasedev->name);
 394     return qemu_file_get_error(f);
 395 }
 396
 397 static void vfio_migration_cleanup(VFIODevice *vbasedev)
 398 {
 399     VFIOMigration *migration = vbasedev->migration;
 400
 401     if (migration->region.mmaps) {
 402         vfio_region_unmap(&migration->region);
 403     }
 404 }
 405
 406 /* ---------------------------------------------------------------------- */
 407
 408 static int vfio_save_setup(QEMUFile *f, void *opaque)
 409 {
 410     VFIODevice *vbasedev = opaque;
 411     VFIOMigration *migration = vbasedev->migration;
 412     int ret;
 413
 414     trace_vfio_save_setup(vbasedev->name);
 415
 416     qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
 417
 418     if (migration->region.mmaps) {
 419         /*
 420          * Calling vfio_region_mmap() from migration thread. Memory API called
 421          * from this function require locking the iothread when called from
 422          * outside the main loop thread.
 423          */
 424         qemu_mutex_lock_iothread();
 425         ret = vfio_region_mmap(&migration->region);
 426         qemu_mutex_unlock_iothread();
 427         if (ret) {
 428             error_report("%s: Failed to mmap VFIO migration region: %s",
 429                          vbasedev->name, strerror(-ret));
 430             error_report("%s: Falling back to slow path", vbasedev->name);
 431         }
 432     }
 433
 434     ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_MASK,
 435                                    VFIO_DEVICE_STATE_V1_SAVING);
 436     if (ret) {
 437         error_report("%s: Failed to set state SAVING", vbasedev->name);
 438         return ret;
 439     }
 440
 441     qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
 442
 443     ret = qemu_file_get_error(f);
 444     if (ret) {
 445         return ret;
 446     }
 447
 448     return 0;
 449 }
 450
 451 static void vfio_save_cleanup(void *opaque)
 452 {
 453     VFIODevice *vbasedev = opaque;
 454
 455     vfio_migration_cleanup(vbasedev);
 456     trace_vfio_save_cleanup(vbasedev->name);
 457 }
 458
 459 static void vfio_save_pending(QEMUFile *f, void *opaque,
 460                               uint64_t threshold_size,
 461                               uint64_t *res_precopy_only,
 462                               uint64_t *res_compatible,
 463                               uint64_t *res_postcopy_only)
 464 {
 465     VFIODevice *vbasedev = opaque;
 466     VFIOMigration *migration = vbasedev->migration;
 467     int ret;
 468
 469     ret = vfio_update_pending(vbasedev);
 470     if (ret) {
 471         return;
 472     }
 473
 474     *res_precopy_only += migration->pending_bytes;
 475
 476     trace_vfio_save_pending(vbasedev->name, *res_precopy_only,
 477                             *res_postcopy_only, *res_compatible);
 478 }
 479
 480 static int vfio_save_iterate(QEMUFile *f, void *opaque)
 481 {
 482     VFIODevice *vbasedev = opaque;
 483     VFIOMigration *migration = vbasedev->migration;
 484     uint64_t data_size;
 485     int ret;
 486
 487     qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
 488
 489     if (migration->pending_bytes == 0) {
 490         ret = vfio_update_pending(vbasedev);
 491         if (ret) {
 492             return ret;
 493         }
 494
 495         if (migration->pending_bytes == 0) {
 496             qemu_put_be64(f, 0);
 497             qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
 498             /* indicates data finished, goto complete phase */
 499             return 1;
 500         }
 501     }
 502
 503     ret = vfio_save_buffer(f, vbasedev, &data_size);
 504     if (ret) {
 505         error_report("%s: vfio_save_buffer failed %s", vbasedev->name,
 506                      strerror(errno));
 507         return ret;
 508     }
 509
 510     qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
 511
 512     ret = qemu_file_get_error(f);
 513     if (ret) {
 514         return ret;
 515     }
 516
 517     /*
 518      * Reset pending_bytes as .save_live_pending is not called during savevm or
 519      * snapshot case, in such case vfio_update_pending() at the start of this
 520      * function updates pending_bytes.
 521      */
 522     migration->pending_bytes = 0;
 523     trace_vfio_save_iterate(vbasedev->name, data_size);
 524     return 0;
 525 }
 526
 527 static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
 528 {
 529     VFIODevice *vbasedev = opaque;
 530     VFIOMigration *migration = vbasedev->migration;
 531     uint64_t data_size;
 532     int ret;
 533
 534     ret = vfio_migration_set_state(vbasedev, ~VFIO_DEVICE_STATE_V1_RUNNING,
 535                                    VFIO_DEVICE_STATE_V1_SAVING);
 536     if (ret) {
 537         error_report("%s: Failed to set state STOP and SAVING",
 538                      vbasedev->name);
 539         return ret;
 540     }
 541
 542     ret = vfio_update_pending(vbasedev);
 543     if (ret) {
 544         return ret;
 545     }
 546
 547     while (migration->pending_bytes > 0) {
 548         qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
 549         ret = vfio_save_buffer(f, vbasedev, &data_size);
 550         if (ret < 0) {
 551             error_report("%s: Failed to save buffer", vbasedev->name);
 552             return ret;
 553         }
 554
 555         if (data_size == 0) {
 556             break;
 557         }
 558
 559         ret = vfio_update_pending(vbasedev);
 560         if (ret) {
 561             return ret;
 562         }
 563     }
 564
 565     qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
 566
 567     ret = qemu_file_get_error(f);
 568     if (ret) {
 569         return ret;
 570     }
 571
 572     ret = vfio_migration_set_state(vbasedev, ~VFIO_DEVICE_STATE_V1_SAVING, 0);
 573     if (ret) {
 574         error_report("%s: Failed to set state STOPPED", vbasedev->name);
 575         return ret;
 576     }
 577
 578     trace_vfio_save_complete_precopy(vbasedev->name);
 579     return ret;
 580 }
 581
 582 static void vfio_save_state(QEMUFile *f, void *opaque)
 583 {
 584     VFIODevice *vbasedev = opaque;
 585     int ret;
 586
 587     ret = vfio_save_device_config_state(f, opaque);
 588     if (ret) {
 589         error_report("%s: Failed to save device config space",
 590                      vbasedev->name);
 591         qemu_file_set_error(f, ret);
 592     }
 593 }
 594
 595 static int vfio_load_setup(QEMUFile *f, void *opaque)
 596 {
 597     VFIODevice *vbasedev = opaque;
 598     VFIOMigration *migration = vbasedev->migration;
 599     int ret = 0;
 600
 601     if (migration->region.mmaps) {
 602         ret = vfio_region_mmap(&migration->region);
 603         if (ret) {
 604             error_report("%s: Failed to mmap VFIO migration region %d: %s",
 605                          vbasedev->name, migration->region.nr,
 606                          strerror(-ret));
 607             error_report("%s: Falling back to slow path", vbasedev->name);
 608         }
 609     }
 610
 611     ret = vfio_migration_set_state(vbasedev, ~VFIO_DEVICE_STATE_MASK,
 612                                    VFIO_DEVICE_STATE_V1_RESUMING);
 613     if (ret) {
 614         error_report("%s: Failed to set state RESUMING", vbasedev->name);
 615         if (migration->region.mmaps) {
 616             vfio_region_unmap(&migration->region);
 617         }
 618     }
 619     return ret;
 620 }
 621
 622 static int vfio_load_cleanup(void *opaque)
 623 {
 624     VFIODevice *vbasedev = opaque;
 625
 626     vfio_migration_cleanup(vbasedev);
 627     trace_vfio_load_cleanup(vbasedev->name);
 628     return 0;
 629 }
 630
 631 static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
 632 {
 633     VFIODevice *vbasedev = opaque;
 634     int ret = 0;
 635     uint64_t data;
 636
 637     data = qemu_get_be64(f);
 638     while (data != VFIO_MIG_FLAG_END_OF_STATE) {
 639
 640         trace_vfio_load_state(vbasedev->name, data);
 641
 642         switch (data) {
 643         case VFIO_MIG_FLAG_DEV_CONFIG_STATE:
 644         {
 645             return vfio_load_device_config_state(f, opaque);
 646         }
 647         case VFIO_MIG_FLAG_DEV_SETUP_STATE:
 648         {
 649             data = qemu_get_be64(f);
 650             if (data == VFIO_MIG_FLAG_END_OF_STATE) {
 651                 return ret;
 652             } else {
 653                 error_report("%s: SETUP STATE: EOS not found 0x%"PRIx64,
 654                              vbasedev->name, data);
 655                 return -EINVAL;
 656             }
 657             break;
 658         }
 659         case VFIO_MIG_FLAG_DEV_DATA_STATE:
 660         {
 661             uint64_t data_size = qemu_get_be64(f);
 662
 663             if (data_size) {
 664                 ret = vfio_load_buffer(f, vbasedev, data_size);
 665                 if (ret < 0) {
 666                     return ret;
 667                 }
 668             }
 669             break;
 670         }
 671         default:
 672             error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data);
 673             return -EINVAL;
 674         }
 675
 676         data = qemu_get_be64(f);
 677         ret = qemu_file_get_error(f);
 678         if (ret) {
 679             return ret;
 680         }
 681     }
 682     return ret;
 683 }
 684
 685 static SaveVMHandlers savevm_vfio_handlers = {
 686     .save_setup = vfio_save_setup,
 687     .save_cleanup = vfio_save_cleanup,
 688     .save_live_pending = vfio_save_pending,
 689     .save_live_iterate = vfio_save_iterate,
 690     .save_live_complete_precopy = vfio_save_complete_precopy,
 691     .save_state = vfio_save_state,
 692     .load_setup = vfio_load_setup,
 693     .load_cleanup = vfio_load_cleanup,
 694     .load_state = vfio_load_state,
 695 };
 696
 697 /* ---------------------------------------------------------------------- */
 698
 699 static void vfio_vmstate_change(void *opaque, bool running, RunState state)
 700 {
 701     VFIODevice *vbasedev = opaque;
 702     VFIOMigration *migration = vbasedev->migration;
 703     uint32_t value, mask;
 704     int ret;
 705
 706     if (vbasedev->migration->vm_running == running) {
 707         return;
 708     }
 709
 710     if (running) {
 711         /*
 712          * Here device state can have one of _SAVING, _RESUMING or _STOP bit.
 713          * Transition from _SAVING to _RUNNING can happen if there is migration
 714          * failure, in that case clear _SAVING bit.
 715          * Transition from _RESUMING to _RUNNING occurs during resuming
 716          * phase, in that case clear _RESUMING bit.
 717          * In both the above cases, set _RUNNING bit.
 718          */
 719         mask = ~VFIO_DEVICE_STATE_MASK;
 720         value = VFIO_DEVICE_STATE_V1_RUNNING;
 721     } else {
 722         /*
 723          * Here device state could be either _RUNNING or _SAVING|_RUNNING. Reset
 724          * _RUNNING bit
 725          */
 726         mask = ~VFIO_DEVICE_STATE_V1_RUNNING;
 727
 728         /*
 729          * When VM state transition to stop for savevm command, device should
 730          * start saving data.
 731          */
 732         if (state == RUN_STATE_SAVE_VM) {
 733             value = VFIO_DEVICE_STATE_V1_SAVING;
 734         } else {
 735             value = 0;
 736         }
 737     }
 738
 739     ret = vfio_migration_set_state(vbasedev, mask, value);
 740     if (ret) {
 741         /*
 742          * Migration should be aborted in this case, but vm_state_notify()
 743          * currently does not support reporting failures.
 744          */
 745         error_report("%s: Failed to set device state 0x%x", vbasedev->name,
 746                      (migration->device_state & mask) | value);
 747         qemu_file_set_error(migrate_get_current()->to_dst_file, ret);
 748     }
 749     vbasedev->migration->vm_running = running;
 750     trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state),
 751             (migration->device_state & mask) | value);
 752 }
 753
 754 static void vfio_migration_state_notifier(Notifier *notifier, void *data)
 755 {
 756     MigrationState *s = data;
 757     VFIOMigration *migration = container_of(notifier, VFIOMigration,
 758                                             migration_state);
 759     VFIODevice *vbasedev = migration->vbasedev;
 760     int ret;
 761
 762     trace_vfio_migration_state_notifier(vbasedev->name,
 763                                         MigrationStatus_str(s->state));
 764
 765     switch (s->state) {
 766     case MIGRATION_STATUS_CANCELLING:
 767     case MIGRATION_STATUS_CANCELLED:
 768     case MIGRATION_STATUS_FAILED:
 769         bytes_transferred = 0;
 770         ret = vfio_migration_set_state(vbasedev,
 771                                        ~(VFIO_DEVICE_STATE_V1_SAVING |
 772                                          VFIO_DEVICE_STATE_V1_RESUMING),
 773                                        VFIO_DEVICE_STATE_V1_RUNNING);
 774         if (ret) {
 775             error_report("%s: Failed to set state RUNNING", vbasedev->name);
 776         }
 777     }
 778 }
 779
 780 static void vfio_migration_exit(VFIODevice *vbasedev)
 781 {
 782     VFIOMigration *migration = vbasedev->migration;
 783
 784     vfio_region_exit(&migration->region);
 785     vfio_region_finalize(&migration->region);
 786     g_free(vbasedev->migration);
 787     vbasedev->migration = NULL;
 788 }
 789
 790 static int vfio_migration_init(VFIODevice *vbasedev,
 791                                struct vfio_region_info *info)
 792 {
 793     int ret;
 794     Object *obj;
 795     VFIOMigration *migration;
 796     char id[256] = "";
 797     g_autofree char *path = NULL, *oid = NULL;
 798
 799     if (!vbasedev->ops->vfio_get_object) {
 800         return -EINVAL;
 801     }
 802
 803     obj = vbasedev->ops->vfio_get_object(vbasedev);
 804     if (!obj) {
 805         return -EINVAL;
 806     }
 807
 808     vbasedev->migration = g_new0(VFIOMigration, 1);
 809     vbasedev->migration->device_state = VFIO_DEVICE_STATE_V1_RUNNING;
 810     vbasedev->migration->vm_running = runstate_is_running();
 811
 812     ret = vfio_region_setup(obj, vbasedev, &vbasedev->migration->region,
 813                             info->index, "migration");
 814     if (ret) {
 815         error_report("%s: Failed to setup VFIO migration region %d: %s",
 816                      vbasedev->name, info->index, strerror(-ret));
 817         goto err;
 818     }
 819
 820     if (!vbasedev->migration->region.size) {
 821         error_report("%s: Invalid zero-sized VFIO migration region %d",
 822                      vbasedev->name, info->index);
 823         ret = -EINVAL;
 824         goto err;
 825     }
 826
 827     migration = vbasedev->migration;
 828     migration->vbasedev = vbasedev;
 829
 830     oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj)));
 831     if (oid) {
 832         path = g_strdup_printf("%s/vfio", oid);
 833     } else {
 834         path = g_strdup("vfio");
 835     }
 836     strpadcpy(id, sizeof(id), path, '\0');
 837
 838     register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers,
 839                          vbasedev);
 840
 841     migration->vm_state = qdev_add_vm_change_state_handler(vbasedev->dev,
 842                                                            vfio_vmstate_change,
 843                                                            vbasedev);
 844     migration->migration_state.notify = vfio_migration_state_notifier;
 845     add_migration_state_change_notifier(&migration->migration_state);
 846     return 0;
 847
 848 err:
 849     vfio_migration_exit(vbasedev);
 850     return ret;
 851 }
 852
 853 /* ---------------------------------------------------------------------- */
 854
 855 int64_t vfio_mig_bytes_transferred(void)
 856 {
 857     return bytes_transferred;
 858 }
 859
 860 int vfio_migration_probe(VFIODevice *vbasedev, Error **errp)
 861 {
 862     VFIOContainer *container = vbasedev->group->container;
 863     struct vfio_region_info *info = NULL;
 864     int ret = -ENOTSUP;
 865
 866     if (!vbasedev->enable_migration || !container->dirty_pages_supported) {
 867         goto add_blocker;
 868     }
 869
 870     ret = vfio_get_dev_region_info(vbasedev,
 871                                    VFIO_REGION_TYPE_MIGRATION_DEPRECATED,
 872                                    VFIO_REGION_SUBTYPE_MIGRATION_DEPRECATED,
 873                                    &info);
 874     if (ret) {
 875         goto add_blocker;
 876     }
 877
 878     ret = vfio_migration_init(vbasedev, info);
 879     if (ret) {
 880         goto add_blocker;
 881     }
 882
 883     trace_vfio_migration_probe(vbasedev->name, info->index);
 884     g_free(info);
 885     return 0;
 886
 887 add_blocker:
 888     error_setg(&vbasedev->migration_blocker,
 889                "VFIO device doesn't support migration");
 890     g_free(info);
 891
 892     ret = migrate_add_blocker(vbasedev->migration_blocker, errp);
 893     if (ret < 0) {
 894         error_free(vbasedev->migration_blocker);
 895         vbasedev->migration_blocker = NULL;
 896     }
 897     return ret;
 898 }
 899
 900 void vfio_migration_finalize(VFIODevice *vbasedev)
 901 {
 902     if (vbasedev->migration) {
 903         VFIOMigration *migration = vbasedev->migration;
 904
 905         remove_migration_state_change_notifier(&migration->migration_state);
 906         qemu_del_vm_change_state_handler(migration->vm_state);
 907         unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev);
 908         vfio_migration_exit(vbasedev);
 909     }
 910
 911     if (vbasedev->migration_blocker) {
 912         migrate_del_blocker(vbasedev->migration_blocker);
 913         error_free(vbasedev->migration_blocker);
 914         vbasedev->migration_blocker = NULL;
 915     }
 916 }