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 "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_prepare(void *opaque, Error **errp)
 339 {
 340     VFIODevice *vbasedev = opaque;
 341
 342     /*
 343      * Snapshot doesn't use postcopy nor background snapshot, so allow snapshot
 344      * even if they are on.
 345      */
 346     if (runstate_check(RUN_STATE_SAVE_VM)) {
 347         return 0;
 348     }
 349
 350     if (migrate_postcopy_ram()) {
 351         error_setg(
 352             errp, "%s: VFIO migration is not supported with postcopy migration",
 353             vbasedev->name);
 354         return -EOPNOTSUPP;
 355     }
 356
 357     if (migrate_background_snapshot()) {
 358         error_setg(
 359             errp,
 360             "%s: VFIO migration is not supported with background snapshot",
 361             vbasedev->name);
 362         return -EOPNOTSUPP;
 363     }
 364
 365     return 0;
 366 }
 367
 368 static int vfio_save_setup(QEMUFile *f, void *opaque)
 369 {
 370     VFIODevice *vbasedev = opaque;
 371     VFIOMigration *migration = vbasedev->migration;
 372     uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
 373
 374     qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
 375
 376     vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
 377     migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
 378                                       stop_copy_size);
 379     migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
 380     if (!migration->data_buffer) {
 381         error_report("%s: Failed to allocate migration data buffer",
 382                      vbasedev->name);
 383         return -ENOMEM;
 384     }
 385
 386     if (vfio_precopy_supported(vbasedev)) {
 387         int ret;
 388
 389         switch (migration->device_state) {
 390         case VFIO_DEVICE_STATE_RUNNING:
 391             ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_PRE_COPY,
 392                                            VFIO_DEVICE_STATE_RUNNING);
 393             if (ret) {
 394                 return ret;
 395             }
 396
 397             vfio_query_precopy_size(migration);
 398
 399             break;
 400         case VFIO_DEVICE_STATE_STOP:
 401             /* vfio_save_complete_precopy() will go to STOP_COPY */
 402             break;
 403         default:
 404             return -EINVAL;
 405         }
 406     }
 407
 408     trace_vfio_save_setup(vbasedev->name, migration->data_buffer_size);
 409
 410     qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
 411
 412     return qemu_file_get_error(f);
 413 }
 414
 415 static void vfio_save_cleanup(void *opaque)
 416 {
 417     VFIODevice *vbasedev = opaque;
 418     VFIOMigration *migration = vbasedev->migration;
 419
 420     /*
 421      * Changing device state from STOP_COPY to STOP can take time. Do it here,
 422      * after migration has completed, so it won't increase downtime.
 423      */
 424     if (migration->device_state == VFIO_DEVICE_STATE_STOP_COPY) {
 425         /*
 426          * If setting the device in STOP state fails, the device should be
 427          * reset. To do so, use ERROR state as a recover state.
 428          */
 429         vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP,
 430                                  VFIO_DEVICE_STATE_ERROR);
 431     }
 432
 433     g_free(migration->data_buffer);
 434     migration->data_buffer = NULL;
 435     migration->precopy_init_size = 0;
 436     migration->precopy_dirty_size = 0;
 437     migration->initial_data_sent = false;
 438     vfio_migration_cleanup(vbasedev);
 439     trace_vfio_save_cleanup(vbasedev->name);
 440 }
 441
 442 static void vfio_state_pending_estimate(void *opaque, uint64_t *must_precopy,
 443                                         uint64_t *can_postcopy)
 444 {
 445     VFIODevice *vbasedev = opaque;
 446     VFIOMigration *migration = vbasedev->migration;
 447
 448     if (!vfio_device_state_is_precopy(vbasedev)) {
 449         return;
 450     }
 451
 452     *must_precopy +=
 453         migration->precopy_init_size + migration->precopy_dirty_size;
 454
 455     trace_vfio_state_pending_estimate(vbasedev->name, *must_precopy,
 456                                       *can_postcopy,
 457                                       migration->precopy_init_size,
 458                                       migration->precopy_dirty_size);
 459 }
 460
 461 /*
 462  * Migration size of VFIO devices can be as little as a few KBs or as big as
 463  * many GBs. This value should be big enough to cover the worst case.
 464  */
 465 #define VFIO_MIG_STOP_COPY_SIZE (100 * GiB)
 466
 467 static void vfio_state_pending_exact(void *opaque, uint64_t *must_precopy,
 468                                      uint64_t *can_postcopy)
 469 {
 470     VFIODevice *vbasedev = opaque;
 471     VFIOMigration *migration = vbasedev->migration;
 472     uint64_t stop_copy_size = VFIO_MIG_STOP_COPY_SIZE;
 473
 474     /*
 475      * If getting pending migration size fails, VFIO_MIG_STOP_COPY_SIZE is
 476      * reported so downtime limit won't be violated.
 477      */
 478     vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
 479     *must_precopy += stop_copy_size;
 480
 481     if (vfio_device_state_is_precopy(vbasedev)) {
 482         vfio_query_precopy_size(migration);
 483
 484         *must_precopy +=
 485             migration->precopy_init_size + migration->precopy_dirty_size;
 486     }
 487
 488     trace_vfio_state_pending_exact(vbasedev->name, *must_precopy, *can_postcopy,
 489                                    stop_copy_size, migration->precopy_init_size,
 490                                    migration->precopy_dirty_size);
 491 }
 492
 493 static bool vfio_is_active_iterate(void *opaque)
 494 {
 495     VFIODevice *vbasedev = opaque;
 496
 497     return vfio_device_state_is_precopy(vbasedev);
 498 }
 499
 500 static int vfio_save_iterate(QEMUFile *f, void *opaque)
 501 {
 502     VFIODevice *vbasedev = opaque;
 503     VFIOMigration *migration = vbasedev->migration;
 504     ssize_t data_size;
 505
 506     data_size = vfio_save_block(f, migration);
 507     if (data_size < 0) {
 508         return data_size;
 509     }
 510
 511     vfio_update_estimated_pending_data(migration, data_size);
 512
 513     if (migrate_switchover_ack() && !migration->precopy_init_size &&
 514         !migration->initial_data_sent) {
 515         qemu_put_be64(f, VFIO_MIG_FLAG_DEV_INIT_DATA_SENT);
 516         migration->initial_data_sent = true;
 517     } else {
 518         qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
 519     }
 520
 521     trace_vfio_save_iterate(vbasedev->name, migration->precopy_init_size,
 522                             migration->precopy_dirty_size);
 523
 524     /*
 525      * A VFIO device's pre-copy dirty_bytes is not guaranteed to reach zero.
 526      * Return 1 so following handlers will not be potentially blocked.
 527      */
 528     return 1;
 529 }
 530
 531 static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
 532 {
 533     VFIODevice *vbasedev = opaque;
 534     ssize_t data_size;
 535     int ret;
 536
 537     /* We reach here with device state STOP or STOP_COPY only */
 538     ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY,
 539                                    VFIO_DEVICE_STATE_STOP);
 540     if (ret) {
 541         return ret;
 542     }
 543
 544     do {
 545         data_size = vfio_save_block(f, vbasedev->migration);
 546         if (data_size < 0) {
 547             return data_size;
 548         }
 549     } while (data_size);
 550
 551     qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
 552     ret = qemu_file_get_error(f);
 553     if (ret) {
 554         return ret;
 555     }
 556
 557     trace_vfio_save_complete_precopy(vbasedev->name, ret);
 558
 559     return ret;
 560 }
 561
 562 static void vfio_save_state(QEMUFile *f, void *opaque)
 563 {
 564     VFIODevice *vbasedev = opaque;
 565     int ret;
 566
 567     ret = vfio_save_device_config_state(f, opaque);
 568     if (ret) {
 569         error_report("%s: Failed to save device config space",
 570                      vbasedev->name);
 571         qemu_file_set_error(f, ret);
 572     }
 573 }
 574
 575 static int vfio_load_setup(QEMUFile *f, void *opaque)
 576 {
 577     VFIODevice *vbasedev = opaque;
 578
 579     return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
 580                                    vbasedev->migration->device_state);
 581 }
 582
 583 static int vfio_load_cleanup(void *opaque)
 584 {
 585     VFIODevice *vbasedev = opaque;
 586
 587     vfio_migration_cleanup(vbasedev);
 588     trace_vfio_load_cleanup(vbasedev->name);
 589
 590     return 0;
 591 }
 592
 593 static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
 594 {
 595     VFIODevice *vbasedev = opaque;
 596     int ret = 0;
 597     uint64_t data;
 598
 599     data = qemu_get_be64(f);
 600     while (data != VFIO_MIG_FLAG_END_OF_STATE) {
 601
 602         trace_vfio_load_state(vbasedev->name, data);
 603
 604         switch (data) {
 605         case VFIO_MIG_FLAG_DEV_CONFIG_STATE:
 606         {
 607             return vfio_load_device_config_state(f, opaque);
 608         }
 609         case VFIO_MIG_FLAG_DEV_SETUP_STATE:
 610         {
 611             data = qemu_get_be64(f);
 612             if (data == VFIO_MIG_FLAG_END_OF_STATE) {
 613                 return ret;
 614             } else {
 615                 error_report("%s: SETUP STATE: EOS not found 0x%"PRIx64,
 616                              vbasedev->name, data);
 617                 return -EINVAL;
 618             }
 619             break;
 620         }
 621         case VFIO_MIG_FLAG_DEV_DATA_STATE:
 622         {
 623             uint64_t data_size = qemu_get_be64(f);
 624
 625             if (data_size) {
 626                 ret = vfio_load_buffer(f, vbasedev, data_size);
 627                 if (ret < 0) {
 628                     return ret;
 629                 }
 630             }
 631             break;
 632         }
 633         case VFIO_MIG_FLAG_DEV_INIT_DATA_SENT:
 634         {
 635             if (!vfio_precopy_supported(vbasedev) ||
 636                 !migrate_switchover_ack()) {
 637                 error_report("%s: Received INIT_DATA_SENT but switchover ack "
 638                              "is not used", vbasedev->name);
 639                 return -EINVAL;
 640             }
 641
 642             ret = qemu_loadvm_approve_switchover();
 643             if (ret) {
 644                 error_report(
 645                     "%s: qemu_loadvm_approve_switchover failed, err=%d (%s)",
 646                     vbasedev->name, ret, strerror(-ret));
 647             }
 648
 649             return ret;
 650         }
 651         default:
 652             error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data);
 653             return -EINVAL;
 654         }
 655
 656         data = qemu_get_be64(f);
 657         ret = qemu_file_get_error(f);
 658         if (ret) {
 659             return ret;
 660         }
 661     }
 662     return ret;
 663 }
 664
 665 static bool vfio_switchover_ack_needed(void *opaque)
 666 {
 667     VFIODevice *vbasedev = opaque;
 668
 669     return vfio_precopy_supported(vbasedev);
 670 }
 671
 672 static const SaveVMHandlers savevm_vfio_handlers = {
 673     .save_prepare = vfio_save_prepare,
 674     .save_setup = vfio_save_setup,
 675     .save_cleanup = vfio_save_cleanup,
 676     .state_pending_estimate = vfio_state_pending_estimate,
 677     .state_pending_exact = vfio_state_pending_exact,
 678     .is_active_iterate = vfio_is_active_iterate,
 679     .save_live_iterate = vfio_save_iterate,
 680     .save_live_complete_precopy = vfio_save_complete_precopy,
 681     .save_state = vfio_save_state,
 682     .load_setup = vfio_load_setup,
 683     .load_cleanup = vfio_load_cleanup,
 684     .load_state = vfio_load_state,
 685     .switchover_ack_needed = vfio_switchover_ack_needed,
 686 };
 687
 688 /* ---------------------------------------------------------------------- */
 689
 690 static void vfio_vmstate_change_prepare(void *opaque, bool running,
 691                                         RunState state)
 692 {
 693     VFIODevice *vbasedev = opaque;
 694     VFIOMigration *migration = vbasedev->migration;
 695     enum vfio_device_mig_state new_state;
 696     int ret;
 697
 698     new_state = migration->device_state == VFIO_DEVICE_STATE_PRE_COPY ?
 699                     VFIO_DEVICE_STATE_PRE_COPY_P2P :
 700                     VFIO_DEVICE_STATE_RUNNING_P2P;
 701
 702     /*
 703      * If setting the device in new_state fails, the device should be reset.
 704      * To do so, use ERROR state as a recover state.
 705      */
 706     ret = vfio_migration_set_state(vbasedev, new_state,
 707                                    VFIO_DEVICE_STATE_ERROR);
 708     if (ret) {
 709         /*
 710          * Migration should be aborted in this case, but vm_state_notify()
 711          * currently does not support reporting failures.
 712          */
 713         if (migrate_get_current()->to_dst_file) {
 714             qemu_file_set_error(migrate_get_current()->to_dst_file, ret);
 715         }
 716     }
 717
 718     trace_vfio_vmstate_change_prepare(vbasedev->name, running,
 719                                       RunState_str(state),
 720                                       mig_state_to_str(new_state));
 721 }
 722
 723 static void vfio_vmstate_change(void *opaque, bool running, RunState state)
 724 {
 725     VFIODevice *vbasedev = opaque;
 726     enum vfio_device_mig_state new_state;
 727     int ret;
 728
 729     if (running) {
 730         new_state = VFIO_DEVICE_STATE_RUNNING;
 731     } else {
 732         new_state =
 733             (vfio_device_state_is_precopy(vbasedev) &&
 734              (state == RUN_STATE_FINISH_MIGRATE || state == RUN_STATE_PAUSED)) ?
 735                 VFIO_DEVICE_STATE_STOP_COPY :
 736                 VFIO_DEVICE_STATE_STOP;
 737     }
 738
 739     /*
 740      * If setting the device in new_state fails, the device should be reset.
 741      * To do so, use ERROR state as a recover state.
 742      */
 743     ret = vfio_migration_set_state(vbasedev, new_state,
 744                                    VFIO_DEVICE_STATE_ERROR);
 745     if (ret) {
 746         /*
 747          * Migration should be aborted in this case, but vm_state_notify()
 748          * currently does not support reporting failures.
 749          */
 750         if (migrate_get_current()->to_dst_file) {
 751             qemu_file_set_error(migrate_get_current()->to_dst_file, ret);
 752         }
 753     }
 754
 755     trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state),
 756                               mig_state_to_str(new_state));
 757 }
 758
 759 static void vfio_migration_state_notifier(Notifier *notifier, void *data)
 760 {
 761     MigrationState *s = data;
 762     VFIOMigration *migration = container_of(notifier, VFIOMigration,
 763                                             migration_state);
 764     VFIODevice *vbasedev = migration->vbasedev;
 765
 766     trace_vfio_migration_state_notifier(vbasedev->name,
 767                                         MigrationStatus_str(s->state));
 768
 769     switch (s->state) {
 770     case MIGRATION_STATUS_CANCELLING:
 771     case MIGRATION_STATUS_CANCELLED:
 772     case MIGRATION_STATUS_FAILED:
 773         /*
 774          * If setting the device in RUNNING state fails, the device should
 775          * be reset. To do so, use ERROR state as a recover state.
 776          */
 777         vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RUNNING,
 778                                  VFIO_DEVICE_STATE_ERROR);
 779     }
 780 }
 781
 782 static void vfio_migration_free(VFIODevice *vbasedev)
 783 {
 784     g_free(vbasedev->migration);
 785     vbasedev->migration = NULL;
 786 }
 787
 788 static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags)
 789 {
 790     uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
 791                                   sizeof(struct vfio_device_feature_migration),
 792                               sizeof(uint64_t))] = {};
 793     struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
 794     struct vfio_device_feature_migration *mig =
 795         (struct vfio_device_feature_migration *)feature->data;
 796
 797     feature->argsz = sizeof(buf);
 798     feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION;
 799     if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
 800         return -errno;
 801     }
 802
 803     *mig_flags = mig->flags;
 804
 805     return 0;
 806 }
 807
 808 static bool vfio_dma_logging_supported(VFIODevice *vbasedev)
 809 {
 810     uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature),
 811                               sizeof(uint64_t))] = {};
 812     struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
 813
 814     feature->argsz = sizeof(buf);
 815     feature->flags = VFIO_DEVICE_FEATURE_PROBE |
 816                      VFIO_DEVICE_FEATURE_DMA_LOGGING_START;
 817
 818     return !ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature);
 819 }
 820
 821 static int vfio_migration_init(VFIODevice *vbasedev)
 822 {
 823     int ret;
 824     Object *obj;
 825     VFIOMigration *migration;
 826     char id[256] = "";
 827     g_autofree char *path = NULL, *oid = NULL;
 828     uint64_t mig_flags = 0;
 829     VMChangeStateHandler *prepare_cb;
 830
 831     if (!vbasedev->ops->vfio_get_object) {
 832         return -EINVAL;
 833     }
 834
 835     obj = vbasedev->ops->vfio_get_object(vbasedev);
 836     if (!obj) {
 837         return -EINVAL;
 838     }
 839
 840     ret = vfio_migration_query_flags(vbasedev, &mig_flags);
 841     if (ret) {
 842         return ret;
 843     }
 844
 845     /* Basic migration functionality must be supported */
 846     if (!(mig_flags & VFIO_MIGRATION_STOP_COPY)) {
 847         return -EOPNOTSUPP;
 848     }
 849
 850     vbasedev->migration = g_new0(VFIOMigration, 1);
 851     migration = vbasedev->migration;
 852     migration->vbasedev = vbasedev;
 853     migration->device_state = VFIO_DEVICE_STATE_RUNNING;
 854     migration->data_fd = -1;
 855     migration->mig_flags = mig_flags;
 856
 857     vbasedev->dirty_pages_supported = vfio_dma_logging_supported(vbasedev);
 858
 859     oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj)));
 860     if (oid) {
 861         path = g_strdup_printf("%s/vfio", oid);
 862     } else {
 863         path = g_strdup("vfio");
 864     }
 865     strpadcpy(id, sizeof(id), path, '\0');
 866
 867     register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers,
 868                          vbasedev);
 869
 870     prepare_cb = migration->mig_flags & VFIO_MIGRATION_P2P ?
 871                      vfio_vmstate_change_prepare :
 872                      NULL;
 873     migration->vm_state = qdev_add_vm_change_state_handler_full(
 874         vbasedev->dev, vfio_vmstate_change, prepare_cb, vbasedev);
 875     migration->migration_state.notify = vfio_migration_state_notifier;
 876     add_migration_state_change_notifier(&migration->migration_state);
 877
 878     return 0;
 879 }
 880
 881 static void vfio_migration_deinit(VFIODevice *vbasedev)
 882 {
 883     VFIOMigration *migration = vbasedev->migration;
 884
 885     remove_migration_state_change_notifier(&migration->migration_state);
 886     qemu_del_vm_change_state_handler(migration->vm_state);
 887     unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev);
 888     vfio_migration_free(vbasedev);
 889     vfio_unblock_multiple_devices_migration();
 890 }
 891
 892 static int vfio_block_migration(VFIODevice *vbasedev, Error *err, Error **errp)
 893 {
 894     if (vbasedev->enable_migration == ON_OFF_AUTO_ON) {
 895         error_propagate(errp, err);
 896         return -EINVAL;
 897     }
 898
 899     vbasedev->migration_blocker = error_copy(err);
 900     error_free(err);
 901
 902     return migrate_add_blocker(&vbasedev->migration_blocker, errp);
 903 }
 904
 905 /* ---------------------------------------------------------------------- */
 906
 907 int64_t vfio_mig_bytes_transferred(void)
 908 {
 909     return bytes_transferred;
 910 }
 911
 912 void vfio_reset_bytes_transferred(void)
 913 {
 914     bytes_transferred = 0;
 915 }
 916
 917 /*
 918  * Return true when either migration initialized or blocker registered.
 919  * Currently only return false when adding blocker fails which will
 920  * de-register vfio device.
 921  */
 922 bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
 923 {
 924     Error *err = NULL;
 925     int ret;
 926
 927     if (vbasedev->enable_migration == ON_OFF_AUTO_OFF) {
 928         error_setg(&err, "%s: Migration is disabled for VFIO device",
 929                    vbasedev->name);
 930         return !vfio_block_migration(vbasedev, err, errp);
 931     }
 932
 933     ret = vfio_migration_init(vbasedev);
 934     if (ret) {
 935         if (ret == -ENOTTY) {
 936             error_setg(&err, "%s: VFIO migration is not supported in kernel",
 937                        vbasedev->name);
 938         } else {
 939             error_setg(&err,
 940                        "%s: Migration couldn't be initialized for VFIO device, "
 941                        "err: %d (%s)",
 942                        vbasedev->name, ret, strerror(-ret));
 943         }
 944
 945         return !vfio_block_migration(vbasedev, err, errp);
 946     }
 947
 948     if (!vbasedev->dirty_pages_supported) {
 949         if (vbasedev->enable_migration == ON_OFF_AUTO_AUTO) {
 950             error_setg(&err,
 951                        "%s: VFIO device doesn't support device dirty tracking",
 952                        vbasedev->name);
 953             goto add_blocker;
 954         }
 955
 956         warn_report("%s: VFIO device doesn't support device dirty tracking",
 957                     vbasedev->name);
 958     }
 959
 960     ret = vfio_block_multiple_devices_migration(vbasedev, errp);
 961     if (ret) {
 962         goto out_deinit;
 963     }
 964
 965     if (vfio_viommu_preset(vbasedev)) {
 966         error_setg(&err, "%s: Migration is currently not supported "
 967                    "with vIOMMU enabled", vbasedev->name);
 968         goto add_blocker;
 969     }
 970
 971     trace_vfio_migration_realize(vbasedev->name);
 972     return true;
 973
 974 add_blocker:
 975     ret = vfio_block_migration(vbasedev, err, errp);
 976 out_deinit:
 977     if (ret) {
 978         vfio_migration_deinit(vbasedev);
 979     }
 980     return !ret;
 981 }
 982
 983 void vfio_migration_exit(VFIODevice *vbasedev)
 984 {
 985     if (vbasedev->migration) {
 986         vfio_migration_deinit(vbasedev);
 987     }
 988
 989     migrate_del_blocker(&vbasedev->migration_blocker);
 990 }