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 "system/runstate.h"
19 #include "hw/vfio/vfio-device.h"
20 #include "hw/vfio/vfio-migration.h"
21 #include "migration/misc.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-multifd.h"
28 #include "qapi/error.h"
29 #include "qapi/qapi-events-vfio.h"
30 #include "exec/ramlist.h"
31 #include "pci.h"
32 #include "trace.h"
33 #include "hw/hw.h"
34 #include "vfio-migration-internal.h"
35
36 /*
37 * This is an arbitrary size based on migration of mlx5 devices, where typically
38 * total device migration size is on the order of 100s of MB. Testing with
39 * larger values, e.g. 128MB and 1GB, did not show a performance improvement.
40 */
41 #define VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE (1 * MiB)
42
43 static unsigned long bytes_transferred;
44
mig_state_to_str(enum vfio_device_mig_state state)45 static const char *mig_state_to_str(enum vfio_device_mig_state state)
46 {
47 switch (state) {
48 case VFIO_DEVICE_STATE_ERROR:
49 return "ERROR";
50 case VFIO_DEVICE_STATE_STOP:
51 return "STOP";
52 case VFIO_DEVICE_STATE_RUNNING:
53 return "RUNNING";
54 case VFIO_DEVICE_STATE_STOP_COPY:
55 return "STOP_COPY";
56 case VFIO_DEVICE_STATE_RESUMING:
57 return "RESUMING";
58 case VFIO_DEVICE_STATE_RUNNING_P2P:
59 return "RUNNING_P2P";
60 case VFIO_DEVICE_STATE_PRE_COPY:
61 return "PRE_COPY";
62 case VFIO_DEVICE_STATE_PRE_COPY_P2P:
63 return "PRE_COPY_P2P";
64 default:
65 return "UNKNOWN STATE";
66 }
67 }
68
69 static QapiVfioMigrationState
mig_state_to_qapi_state(enum vfio_device_mig_state state)70 mig_state_to_qapi_state(enum vfio_device_mig_state state)
71 {
72 switch (state) {
73 case VFIO_DEVICE_STATE_STOP:
74 return QAPI_VFIO_MIGRATION_STATE_STOP;
75 case VFIO_DEVICE_STATE_RUNNING:
76 return QAPI_VFIO_MIGRATION_STATE_RUNNING;
77 case VFIO_DEVICE_STATE_STOP_COPY:
78 return QAPI_VFIO_MIGRATION_STATE_STOP_COPY;
79 case VFIO_DEVICE_STATE_RESUMING:
80 return QAPI_VFIO_MIGRATION_STATE_RESUMING;
81 case VFIO_DEVICE_STATE_RUNNING_P2P:
82 return QAPI_VFIO_MIGRATION_STATE_RUNNING_P2P;
83 case VFIO_DEVICE_STATE_PRE_COPY:
84 return QAPI_VFIO_MIGRATION_STATE_PRE_COPY;
85 case VFIO_DEVICE_STATE_PRE_COPY_P2P:
86 return QAPI_VFIO_MIGRATION_STATE_PRE_COPY_P2P;
87 default:
88 g_assert_not_reached();
89 }
90 }
91
vfio_migration_send_event(VFIODevice * vbasedev)92 static void vfio_migration_send_event(VFIODevice *vbasedev)
93 {
94 VFIOMigration *migration = vbasedev->migration;
95 DeviceState *dev = vbasedev->dev;
96 g_autofree char *qom_path = NULL;
97 Object *obj;
98
99 if (!vbasedev->migration_events) {
100 return;
101 }
102
103 g_assert(vbasedev->ops->vfio_get_object);
104 obj = vbasedev->ops->vfio_get_object(vbasedev);
105 g_assert(obj);
106 qom_path = object_get_canonical_path(obj);
107
108 qapi_event_send_vfio_migration(
109 dev->id, qom_path, mig_state_to_qapi_state(migration->device_state));
110 }
111
vfio_migration_set_device_state(VFIODevice * vbasedev,enum vfio_device_mig_state state)112 static void vfio_migration_set_device_state(VFIODevice *vbasedev,
113 enum vfio_device_mig_state state)
114 {
115 VFIOMigration *migration = vbasedev->migration;
116
117 trace_vfio_migration_set_device_state(vbasedev->name,
118 mig_state_to_str(state));
119
120 migration->device_state = state;
121 vfio_migration_send_event(vbasedev);
122 }
123
vfio_migration_set_state(VFIODevice * vbasedev,enum vfio_device_mig_state new_state,enum vfio_device_mig_state recover_state,Error ** errp)124 int vfio_migration_set_state(VFIODevice *vbasedev,
125 enum vfio_device_mig_state new_state,
126 enum vfio_device_mig_state recover_state,
127 Error **errp)
128 {
129 VFIOMigration *migration = vbasedev->migration;
130 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
131 sizeof(struct vfio_device_feature_mig_state),
132 sizeof(uint64_t))] = {};
133 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
134 struct vfio_device_feature_mig_state *mig_state =
135 (struct vfio_device_feature_mig_state *)feature->data;
136 int ret;
137 g_autofree char *error_prefix =
138 g_strdup_printf("%s: Failed setting device state to %s.",
139 vbasedev->name, mig_state_to_str(new_state));
140
141 trace_vfio_migration_set_state(vbasedev->name, mig_state_to_str(new_state),
142 mig_state_to_str(recover_state));
143
144 if (new_state == migration->device_state) {
145 return 0;
146 }
147
148 feature->argsz = sizeof(buf);
149 feature->flags =
150 VFIO_DEVICE_FEATURE_SET | VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE;
151 mig_state->device_state = new_state;
152 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
153 /* Try to set the device in some good state */
154 ret = -errno;
155
156 if (recover_state == VFIO_DEVICE_STATE_ERROR) {
157 error_setg_errno(errp, errno,
158 "%s Recover state is ERROR. Resetting device",
159 error_prefix);
160
161 goto reset_device;
162 }
163
164 error_setg_errno(errp, errno,
165 "%s Setting device in recover state %s",
166 error_prefix, mig_state_to_str(recover_state));
167
168 mig_state->device_state = recover_state;
169 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
170 ret = -errno;
171 /*
172 * If setting the device in recover state fails, report
173 * the error here and propagate the first error.
174 */
175 error_report(
176 "%s: Failed setting device in recover state, err: %s. Resetting device",
177 vbasedev->name, strerror(errno));
178
179 goto reset_device;
180 }
181
182 vfio_migration_set_device_state(vbasedev, recover_state);
183
184 return ret;
185 }
186
187 vfio_migration_set_device_state(vbasedev, new_state);
188 if (mig_state->data_fd != -1) {
189 if (migration->data_fd != -1) {
190 /*
191 * This can happen if the device is asynchronously reset and
192 * terminates a data transfer.
193 */
194 error_setg(errp, "%s: data_fd out of sync", vbasedev->name);
195 close(mig_state->data_fd);
196
197 return -EBADF;
198 }
199
200 migration->data_fd = mig_state->data_fd;
201 }
202
203 return 0;
204
205 reset_device:
206 if (ioctl(vbasedev->fd, VFIO_DEVICE_RESET)) {
207 hw_error("%s: Failed resetting device, err: %s", vbasedev->name,
208 strerror(errno));
209 }
210
211 vfio_migration_set_device_state(vbasedev, VFIO_DEVICE_STATE_RUNNING);
212
213 return ret;
214 }
215
216 /*
217 * Some device state transitions require resetting the device if they fail.
218 * This function sets the device in new_state and resets the device if that
219 * fails. Reset is done by using ERROR as the recover state.
220 */
221 static int
vfio_migration_set_state_or_reset(VFIODevice * vbasedev,enum vfio_device_mig_state new_state,Error ** errp)222 vfio_migration_set_state_or_reset(VFIODevice *vbasedev,
223 enum vfio_device_mig_state new_state,
224 Error **errp)
225 {
226 return vfio_migration_set_state(vbasedev, new_state,
227 VFIO_DEVICE_STATE_ERROR, errp);
228 }
229
vfio_load_buffer(QEMUFile * f,VFIODevice * vbasedev,uint64_t data_size)230 static int vfio_load_buffer(QEMUFile *f, VFIODevice *vbasedev,
231 uint64_t data_size)
232 {
233 VFIOMigration *migration = vbasedev->migration;
234 int ret;
235
236 ret = qemu_file_get_to_fd(f, migration->data_fd, data_size);
237 trace_vfio_load_state_device_data(vbasedev->name, data_size, ret);
238
239 return ret;
240 }
241
vfio_save_device_config_state(QEMUFile * f,void * opaque,Error ** errp)242 int vfio_save_device_config_state(QEMUFile *f, void *opaque, Error **errp)
243 {
244 VFIODevice *vbasedev = opaque;
245 int ret;
246
247 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE);
248
249 if (vbasedev->ops && vbasedev->ops->vfio_save_config) {
250 ret = vbasedev->ops->vfio_save_config(vbasedev, f, errp);
251 if (ret) {
252 return ret;
253 }
254 }
255
256 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
257
258 trace_vfio_save_device_config_state(vbasedev->name);
259
260 ret = qemu_file_get_error(f);
261 if (ret < 0) {
262 error_setg_errno(errp, -ret, "Failed to save state");
263 }
264 return ret;
265 }
266
vfio_load_device_config_state(QEMUFile * f,void * opaque)267 int vfio_load_device_config_state(QEMUFile *f, void *opaque)
268 {
269 VFIODevice *vbasedev = opaque;
270 uint64_t data;
271
272 trace_vfio_load_device_config_state_start(vbasedev->name);
273
274 if (vbasedev->ops && vbasedev->ops->vfio_load_config) {
275 int ret;
276
277 ret = vbasedev->ops->vfio_load_config(vbasedev, f);
278 if (ret) {
279 error_report("%s: Failed to load device config space",
280 vbasedev->name);
281 return ret;
282 }
283 }
284
285 data = qemu_get_be64(f);
286 if (data != VFIO_MIG_FLAG_END_OF_STATE) {
287 error_report("%s: Failed loading device config space, "
288 "end flag incorrect 0x%"PRIx64, vbasedev->name, data);
289 return -EINVAL;
290 }
291
292 trace_vfio_load_device_config_state_end(vbasedev->name);
293 return qemu_file_get_error(f);
294 }
295
vfio_migration_cleanup(VFIODevice * vbasedev)296 static void vfio_migration_cleanup(VFIODevice *vbasedev)
297 {
298 VFIOMigration *migration = vbasedev->migration;
299
300 close(migration->data_fd);
301 migration->data_fd = -1;
302 }
303
vfio_query_stop_copy_size(VFIODevice * vbasedev,uint64_t * stop_copy_size)304 static int vfio_query_stop_copy_size(VFIODevice *vbasedev,
305 uint64_t *stop_copy_size)
306 {
307 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
308 sizeof(struct vfio_device_feature_mig_data_size),
309 sizeof(uint64_t))] = {};
310 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
311 struct vfio_device_feature_mig_data_size *mig_data_size =
312 (struct vfio_device_feature_mig_data_size *)feature->data;
313
314 feature->argsz = sizeof(buf);
315 feature->flags =
316 VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIG_DATA_SIZE;
317
318 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
319 return -errno;
320 }
321
322 *stop_copy_size = mig_data_size->stop_copy_length;
323
324 return 0;
325 }
326
vfio_query_precopy_size(VFIOMigration * migration)327 static int vfio_query_precopy_size(VFIOMigration *migration)
328 {
329 struct vfio_precopy_info precopy = {
330 .argsz = sizeof(precopy),
331 };
332
333 migration->precopy_init_size = 0;
334 migration->precopy_dirty_size = 0;
335
336 if (ioctl(migration->data_fd, VFIO_MIG_GET_PRECOPY_INFO, &precopy)) {
337 return -errno;
338 }
339
340 migration->precopy_init_size = precopy.initial_bytes;
341 migration->precopy_dirty_size = precopy.dirty_bytes;
342
343 return 0;
344 }
345
346 /* Returns the size of saved data on success and -errno on error */
vfio_save_block(QEMUFile * f,VFIOMigration * migration)347 static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration)
348 {
349 ssize_t data_size;
350
351 data_size = read(migration->data_fd, migration->data_buffer,
352 migration->data_buffer_size);
353 if (data_size < 0) {
354 /*
355 * Pre-copy emptied all the device state for now. For more information,
356 * please refer to the Linux kernel VFIO uAPI.
357 */
358 if (errno == ENOMSG) {
359 if (!migration->event_precopy_empty_hit) {
360 trace_vfio_save_block_precopy_empty_hit(migration->vbasedev->name);
361 migration->event_precopy_empty_hit = true;
362 }
363 return 0;
364 }
365
366 return -errno;
367 }
368 if (data_size == 0) {
369 return 0;
370 }
371
372 /* Non-empty read: re-arm the trace event */
373 migration->event_precopy_empty_hit = false;
374
375 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
376 qemu_put_be64(f, data_size);
377 qemu_put_buffer(f, migration->data_buffer, data_size);
378 vfio_migration_add_bytes_transferred(data_size);
379
380 trace_vfio_save_block(migration->vbasedev->name, data_size);
381
382 return qemu_file_get_error(f) ?: data_size;
383 }
384
vfio_update_estimated_pending_data(VFIOMigration * migration,uint64_t data_size)385 static void vfio_update_estimated_pending_data(VFIOMigration *migration,
386 uint64_t data_size)
387 {
388 if (!data_size) {
389 /*
390 * Pre-copy emptied all the device state for now, update estimated sizes
391 * accordingly.
392 */
393 migration->precopy_init_size = 0;
394 migration->precopy_dirty_size = 0;
395
396 return;
397 }
398
399 if (migration->precopy_init_size) {
400 uint64_t init_size = MIN(migration->precopy_init_size, data_size);
401
402 migration->precopy_init_size -= init_size;
403 data_size -= init_size;
404 }
405
406 migration->precopy_dirty_size -= MIN(migration->precopy_dirty_size,
407 data_size);
408 }
409
vfio_precopy_supported(VFIODevice * vbasedev)410 static bool vfio_precopy_supported(VFIODevice *vbasedev)
411 {
412 VFIOMigration *migration = vbasedev->migration;
413
414 return migration->mig_flags & VFIO_MIGRATION_PRE_COPY;
415 }
416
417 /* ---------------------------------------------------------------------- */
418
vfio_save_prepare(void * opaque,Error ** errp)419 static int vfio_save_prepare(void *opaque, Error **errp)
420 {
421 VFIODevice *vbasedev = opaque;
422
423 /*
424 * Snapshot doesn't use postcopy nor background snapshot, so allow snapshot
425 * even if they are on.
426 */
427 if (runstate_check(RUN_STATE_SAVE_VM)) {
428 return 0;
429 }
430
431 if (migrate_postcopy_ram()) {
432 error_setg(
433 errp, "%s: VFIO migration is not supported with postcopy migration",
434 vbasedev->name);
435 return -EOPNOTSUPP;
436 }
437
438 if (migrate_background_snapshot()) {
439 error_setg(
440 errp,
441 "%s: VFIO migration is not supported with background snapshot",
442 vbasedev->name);
443 return -EOPNOTSUPP;
444 }
445
446 return 0;
447 }
448
vfio_save_setup(QEMUFile * f,void * opaque,Error ** errp)449 static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp)
450 {
451 VFIODevice *vbasedev = opaque;
452 VFIOMigration *migration = vbasedev->migration;
453 uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
454 int ret;
455
456 if (!vfio_multifd_setup(vbasedev, false, errp)) {
457 return -EINVAL;
458 }
459
460 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
461
462 vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
463 migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
464 stop_copy_size);
465 migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
466 if (!migration->data_buffer) {
467 error_setg(errp, "%s: Failed to allocate migration data buffer",
468 vbasedev->name);
469 return -ENOMEM;
470 }
471
472 migration->event_save_iterate_started = false;
473 migration->event_precopy_empty_hit = false;
474
475 if (vfio_precopy_supported(vbasedev)) {
476 switch (migration->device_state) {
477 case VFIO_DEVICE_STATE_RUNNING:
478 ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_PRE_COPY,
479 VFIO_DEVICE_STATE_RUNNING, errp);
480 if (ret) {
481 return ret;
482 }
483
484 vfio_query_precopy_size(migration);
485
486 break;
487 case VFIO_DEVICE_STATE_STOP:
488 /* vfio_save_complete_precopy() will go to STOP_COPY */
489 break;
490 default:
491 error_setg(errp, "%s: Invalid device state %d", vbasedev->name,
492 migration->device_state);
493 return -EINVAL;
494 }
495 }
496
497 trace_vfio_save_setup(vbasedev->name, migration->data_buffer_size);
498
499 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
500
501 ret = qemu_file_get_error(f);
502 if (ret < 0) {
503 error_setg_errno(errp, -ret, "%s: save setup failed", vbasedev->name);
504 }
505
506 return ret;
507 }
508
vfio_save_cleanup(void * opaque)509 static void vfio_save_cleanup(void *opaque)
510 {
511 VFIODevice *vbasedev = opaque;
512 VFIOMigration *migration = vbasedev->migration;
513 Error *local_err = NULL;
514 int ret;
515
516 /* Currently a NOP, done for symmetry with load_cleanup() */
517 vfio_multifd_cleanup(vbasedev);
518
519 /*
520 * Changing device state from STOP_COPY to STOP can take time. Do it here,
521 * after migration has completed, so it won't increase downtime.
522 */
523 if (migration->device_state == VFIO_DEVICE_STATE_STOP_COPY) {
524 ret = vfio_migration_set_state_or_reset(vbasedev,
525 VFIO_DEVICE_STATE_STOP,
526 &local_err);
527 if (ret) {
528 error_report_err(local_err);
529 }
530 }
531
532 g_free(migration->data_buffer);
533 migration->data_buffer = NULL;
534 migration->precopy_init_size = 0;
535 migration->precopy_dirty_size = 0;
536 migration->initial_data_sent = false;
537 vfio_migration_cleanup(vbasedev);
538 trace_vfio_save_cleanup(vbasedev->name);
539 }
540
vfio_state_pending_estimate(void * opaque,uint64_t * must_precopy,uint64_t * can_postcopy)541 static void vfio_state_pending_estimate(void *opaque, uint64_t *must_precopy,
542 uint64_t *can_postcopy)
543 {
544 VFIODevice *vbasedev = opaque;
545 VFIOMigration *migration = vbasedev->migration;
546
547 if (!vfio_device_state_is_precopy(vbasedev)) {
548 return;
549 }
550
551 *must_precopy +=
552 migration->precopy_init_size + migration->precopy_dirty_size;
553
554 trace_vfio_state_pending_estimate(vbasedev->name, *must_precopy,
555 *can_postcopy,
556 migration->precopy_init_size,
557 migration->precopy_dirty_size);
558 }
559
560 /*
561 * Migration size of VFIO devices can be as little as a few KBs or as big as
562 * many GBs. This value should be big enough to cover the worst case.
563 */
564 #define VFIO_MIG_STOP_COPY_SIZE (100 * GiB)
565
vfio_state_pending_exact(void * opaque,uint64_t * must_precopy,uint64_t * can_postcopy)566 static void vfio_state_pending_exact(void *opaque, uint64_t *must_precopy,
567 uint64_t *can_postcopy)
568 {
569 VFIODevice *vbasedev = opaque;
570 VFIOMigration *migration = vbasedev->migration;
571 uint64_t stop_copy_size = VFIO_MIG_STOP_COPY_SIZE;
572
573 /*
574 * If getting pending migration size fails, VFIO_MIG_STOP_COPY_SIZE is
575 * reported so downtime limit won't be violated.
576 */
577 vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
578 *must_precopy += stop_copy_size;
579
580 if (vfio_device_state_is_precopy(vbasedev)) {
581 vfio_query_precopy_size(migration);
582 }
583
584 trace_vfio_state_pending_exact(vbasedev->name, *must_precopy, *can_postcopy,
585 stop_copy_size, migration->precopy_init_size,
586 migration->precopy_dirty_size);
587 }
588
vfio_is_active_iterate(void * opaque)589 static bool vfio_is_active_iterate(void *opaque)
590 {
591 VFIODevice *vbasedev = opaque;
592
593 return vfio_device_state_is_precopy(vbasedev);
594 }
595
596 /*
597 * Note about migration rate limiting: VFIO migration buffer size is currently
598 * limited to 1MB, so there is no need to check if migration rate exceeded (as
599 * in the worst case it will exceed by 1MB). However, if the buffer size is
600 * later changed to a bigger value, migration rate should be enforced here.
601 */
vfio_save_iterate(QEMUFile * f,void * opaque)602 static int vfio_save_iterate(QEMUFile *f, void *opaque)
603 {
604 VFIODevice *vbasedev = opaque;
605 VFIOMigration *migration = vbasedev->migration;
606 ssize_t data_size;
607
608 if (!migration->event_save_iterate_started) {
609 trace_vfio_save_iterate_start(vbasedev->name);
610 migration->event_save_iterate_started = true;
611 }
612
613 data_size = vfio_save_block(f, migration);
614 if (data_size < 0) {
615 return data_size;
616 }
617
618 vfio_update_estimated_pending_data(migration, data_size);
619
620 if (migrate_switchover_ack() && !migration->precopy_init_size &&
621 !migration->initial_data_sent) {
622 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_INIT_DATA_SENT);
623 migration->initial_data_sent = true;
624 } else {
625 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
626 }
627
628 trace_vfio_save_iterate(vbasedev->name, migration->precopy_init_size,
629 migration->precopy_dirty_size);
630
631 return !migration->precopy_init_size && !migration->precopy_dirty_size;
632 }
633
vfio_save_complete_precopy(QEMUFile * f,void * opaque)634 static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
635 {
636 VFIODevice *vbasedev = opaque;
637 ssize_t data_size;
638 int ret;
639 Error *local_err = NULL;
640
641 if (vfio_multifd_transfer_enabled(vbasedev)) {
642 vfio_multifd_emit_dummy_eos(vbasedev, f);
643 return 0;
644 }
645
646 trace_vfio_save_complete_precopy_start(vbasedev->name);
647
648 /* We reach here with device state STOP or STOP_COPY only */
649 ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY,
650 VFIO_DEVICE_STATE_STOP, &local_err);
651 if (ret) {
652 error_report_err(local_err);
653 return ret;
654 }
655
656 do {
657 data_size = vfio_save_block(f, vbasedev->migration);
658 if (data_size < 0) {
659 return data_size;
660 }
661 } while (data_size);
662
663 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
664 ret = qemu_file_get_error(f);
665
666 trace_vfio_save_complete_precopy(vbasedev->name, ret);
667
668 return ret;
669 }
670
vfio_save_state(QEMUFile * f,void * opaque)671 static void vfio_save_state(QEMUFile *f, void *opaque)
672 {
673 VFIODevice *vbasedev = opaque;
674 Error *local_err = NULL;
675 int ret;
676
677 if (vfio_multifd_transfer_enabled(vbasedev)) {
678 vfio_multifd_emit_dummy_eos(vbasedev, f);
679 return;
680 }
681
682 ret = vfio_save_device_config_state(f, opaque, &local_err);
683 if (ret) {
684 error_prepend(&local_err,
685 "vfio: Failed to save device config space of %s - ",
686 vbasedev->name);
687 qemu_file_set_error_obj(f, ret, local_err);
688 }
689 }
690
vfio_load_setup(QEMUFile * f,void * opaque,Error ** errp)691 static int vfio_load_setup(QEMUFile *f, void *opaque, Error **errp)
692 {
693 VFIODevice *vbasedev = opaque;
694 VFIOMigration *migration = vbasedev->migration;
695 int ret;
696
697 if (!vfio_multifd_setup(vbasedev, true, errp)) {
698 return -EINVAL;
699 }
700
701 ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
702 migration->device_state, errp);
703 if (ret) {
704 return ret;
705 }
706
707 return 0;
708 }
709
vfio_load_cleanup(void * opaque)710 static int vfio_load_cleanup(void *opaque)
711 {
712 VFIODevice *vbasedev = opaque;
713
714 vfio_multifd_cleanup(vbasedev);
715
716 vfio_migration_cleanup(vbasedev);
717 trace_vfio_load_cleanup(vbasedev->name);
718
719 return 0;
720 }
721
vfio_load_state(QEMUFile * f,void * opaque,int version_id)722 static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
723 {
724 VFIODevice *vbasedev = opaque;
725 int ret = 0;
726 uint64_t data;
727
728 data = qemu_get_be64(f);
729 while (data != VFIO_MIG_FLAG_END_OF_STATE) {
730
731 trace_vfio_load_state(vbasedev->name, data);
732
733 switch (data) {
734 case VFIO_MIG_FLAG_DEV_CONFIG_STATE:
735 {
736 if (vfio_multifd_transfer_enabled(vbasedev)) {
737 error_report("%s: got DEV_CONFIG_STATE in main migration "
738 "channel but doing multifd transfer",
739 vbasedev->name);
740 return -EINVAL;
741 }
742
743 return vfio_load_device_config_state(f, opaque);
744 }
745 case VFIO_MIG_FLAG_DEV_SETUP_STATE:
746 {
747 data = qemu_get_be64(f);
748 if (data == VFIO_MIG_FLAG_END_OF_STATE) {
749 return ret;
750 } else {
751 error_report("%s: SETUP STATE: EOS not found 0x%"PRIx64,
752 vbasedev->name, data);
753 return -EINVAL;
754 }
755 break;
756 }
757 case VFIO_MIG_FLAG_DEV_DATA_STATE:
758 {
759 uint64_t data_size = qemu_get_be64(f);
760
761 if (data_size) {
762 ret = vfio_load_buffer(f, vbasedev, data_size);
763 if (ret < 0) {
764 return ret;
765 }
766 }
767 break;
768 }
769 case VFIO_MIG_FLAG_DEV_INIT_DATA_SENT:
770 {
771 if (!vfio_precopy_supported(vbasedev) ||
772 !migrate_switchover_ack()) {
773 error_report("%s: Received INIT_DATA_SENT but switchover ack "
774 "is not used", vbasedev->name);
775 return -EINVAL;
776 }
777
778 ret = qemu_loadvm_approve_switchover();
779 if (ret) {
780 error_report(
781 "%s: qemu_loadvm_approve_switchover failed, err=%d (%s)",
782 vbasedev->name, ret, strerror(-ret));
783 }
784
785 return ret;
786 }
787 default:
788 error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data);
789 return -EINVAL;
790 }
791
792 data = qemu_get_be64(f);
793 ret = qemu_file_get_error(f);
794 if (ret) {
795 return ret;
796 }
797 }
798 return ret;
799 }
800
vfio_switchover_ack_needed(void * opaque)801 static bool vfio_switchover_ack_needed(void *opaque)
802 {
803 VFIODevice *vbasedev = opaque;
804
805 return vfio_precopy_supported(vbasedev);
806 }
807
vfio_switchover_start(void * opaque)808 static int vfio_switchover_start(void *opaque)
809 {
810 VFIODevice *vbasedev = opaque;
811
812 if (vfio_multifd_transfer_enabled(vbasedev)) {
813 return vfio_multifd_switchover_start(vbasedev);
814 }
815
816 return 0;
817 }
818
819 static const SaveVMHandlers savevm_vfio_handlers = {
820 .save_prepare = vfio_save_prepare,
821 .save_setup = vfio_save_setup,
822 .save_cleanup = vfio_save_cleanup,
823 .state_pending_estimate = vfio_state_pending_estimate,
824 .state_pending_exact = vfio_state_pending_exact,
825 .is_active_iterate = vfio_is_active_iterate,
826 .save_live_iterate = vfio_save_iterate,
827 .save_live_complete_precopy = vfio_save_complete_precopy,
828 .save_state = vfio_save_state,
829 .load_setup = vfio_load_setup,
830 .load_cleanup = vfio_load_cleanup,
831 .load_state = vfio_load_state,
832 .switchover_ack_needed = vfio_switchover_ack_needed,
833 /*
834 * Multifd support
835 */
836 .load_state_buffer = vfio_multifd_load_state_buffer,
837 .switchover_start = vfio_switchover_start,
838 .save_live_complete_precopy_thread = vfio_multifd_save_complete_precopy_thread,
839 };
840
841 /* ---------------------------------------------------------------------- */
842
vfio_vmstate_change_prepare(void * opaque,bool running,RunState state)843 static void vfio_vmstate_change_prepare(void *opaque, bool running,
844 RunState state)
845 {
846 VFIODevice *vbasedev = opaque;
847 VFIOMigration *migration = vbasedev->migration;
848 enum vfio_device_mig_state new_state;
849 Error *local_err = NULL;
850 int ret;
851
852 new_state = migration->device_state == VFIO_DEVICE_STATE_PRE_COPY ?
853 VFIO_DEVICE_STATE_PRE_COPY_P2P :
854 VFIO_DEVICE_STATE_RUNNING_P2P;
855
856 ret = vfio_migration_set_state_or_reset(vbasedev, new_state, &local_err);
857 if (ret) {
858 /*
859 * Migration should be aborted in this case, but vm_state_notify()
860 * currently does not support reporting failures.
861 */
862 migration_file_set_error(ret, local_err);
863 }
864
865 trace_vfio_vmstate_change_prepare(vbasedev->name, running,
866 RunState_str(state),
867 mig_state_to_str(new_state));
868 }
869
vfio_vmstate_change(void * opaque,bool running,RunState state)870 static void vfio_vmstate_change(void *opaque, bool running, RunState state)
871 {
872 VFIODevice *vbasedev = opaque;
873 enum vfio_device_mig_state new_state;
874 Error *local_err = NULL;
875 int ret;
876
877 if (running) {
878 new_state = VFIO_DEVICE_STATE_RUNNING;
879 } else {
880 new_state =
881 (vfio_device_state_is_precopy(vbasedev) &&
882 (state == RUN_STATE_FINISH_MIGRATE || state == RUN_STATE_PAUSED)) ?
883 VFIO_DEVICE_STATE_STOP_COPY :
884 VFIO_DEVICE_STATE_STOP;
885 }
886
887 ret = vfio_migration_set_state_or_reset(vbasedev, new_state, &local_err);
888 if (ret) {
889 /*
890 * Migration should be aborted in this case, but vm_state_notify()
891 * currently does not support reporting failures.
892 */
893 migration_file_set_error(ret, local_err);
894 }
895
896 trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state),
897 mig_state_to_str(new_state));
898 }
899
vfio_migration_state_notifier(NotifierWithReturn * notifier,MigrationEvent * e,Error ** errp)900 static int vfio_migration_state_notifier(NotifierWithReturn *notifier,
901 MigrationEvent *e, Error **errp)
902 {
903 VFIOMigration *migration = container_of(notifier, VFIOMigration,
904 migration_state);
905 VFIODevice *vbasedev = migration->vbasedev;
906 Error *local_err = NULL;
907 int ret;
908
909 trace_vfio_migration_state_notifier(vbasedev->name, e->type);
910
911 if (e->type == MIG_EVENT_PRECOPY_FAILED) {
912 /*
913 * MigrationNotifyFunc may not return an error code and an Error
914 * object for MIG_EVENT_PRECOPY_FAILED. Hence, report the error
915 * locally and ignore the errp argument.
916 */
917 ret = vfio_migration_set_state_or_reset(vbasedev,
918 VFIO_DEVICE_STATE_RUNNING,
919 &local_err);
920 if (ret) {
921 error_report_err(local_err);
922 }
923 }
924 return 0;
925 }
926
vfio_migration_free(VFIODevice * vbasedev)927 static void vfio_migration_free(VFIODevice *vbasedev)
928 {
929 g_free(vbasedev->migration);
930 vbasedev->migration = NULL;
931 }
932
vfio_migration_query_flags(VFIODevice * vbasedev,uint64_t * mig_flags)933 static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags)
934 {
935 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
936 sizeof(struct vfio_device_feature_migration),
937 sizeof(uint64_t))] = {};
938 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
939 struct vfio_device_feature_migration *mig =
940 (struct vfio_device_feature_migration *)feature->data;
941
942 feature->argsz = sizeof(buf);
943 feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION;
944 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
945 return -errno;
946 }
947
948 *mig_flags = mig->flags;
949
950 return 0;
951 }
952
vfio_dma_logging_supported(VFIODevice * vbasedev)953 static bool vfio_dma_logging_supported(VFIODevice *vbasedev)
954 {
955 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature),
956 sizeof(uint64_t))] = {};
957 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
958
959 feature->argsz = sizeof(buf);
960 feature->flags = VFIO_DEVICE_FEATURE_PROBE |
961 VFIO_DEVICE_FEATURE_DMA_LOGGING_START;
962
963 return !ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature);
964 }
965
vfio_migration_init(VFIODevice * vbasedev)966 static int vfio_migration_init(VFIODevice *vbasedev)
967 {
968 int ret;
969 Object *obj;
970 VFIOMigration *migration;
971 char id[256] = "";
972 g_autofree char *path = NULL, *oid = NULL;
973 uint64_t mig_flags = 0;
974 VMChangeStateHandler *prepare_cb;
975
976 if (!vbasedev->ops->vfio_get_object) {
977 return -EINVAL;
978 }
979
980 obj = vbasedev->ops->vfio_get_object(vbasedev);
981 if (!obj) {
982 return -EINVAL;
983 }
984
985 ret = vfio_migration_query_flags(vbasedev, &mig_flags);
986 if (ret) {
987 return ret;
988 }
989
990 /* Basic migration functionality must be supported */
991 if (!(mig_flags & VFIO_MIGRATION_STOP_COPY)) {
992 return -EOPNOTSUPP;
993 }
994
995 vbasedev->migration = g_new0(VFIOMigration, 1);
996 migration = vbasedev->migration;
997 migration->vbasedev = vbasedev;
998 migration->device_state = VFIO_DEVICE_STATE_RUNNING;
999 migration->data_fd = -1;
1000 migration->mig_flags = mig_flags;
1001
1002 vbasedev->dirty_pages_supported = vfio_dma_logging_supported(vbasedev);
1003
1004 oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj)));
1005 if (oid) {
1006 path = g_strdup_printf("%s/vfio", oid);
1007 } else {
1008 path = g_strdup("vfio");
1009 }
1010 strpadcpy(id, sizeof(id), path, '\0');
1011
1012 register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers,
1013 vbasedev);
1014
1015 prepare_cb = migration->mig_flags & VFIO_MIGRATION_P2P ?
1016 vfio_vmstate_change_prepare :
1017 NULL;
1018 migration->vm_state = qdev_add_vm_change_state_handler_full(
1019 vbasedev->dev, vfio_vmstate_change, prepare_cb, NULL, vbasedev);
1020 migration_add_notifier(&migration->migration_state,
1021 vfio_migration_state_notifier);
1022
1023 return 0;
1024 }
1025
1026 static Error *multiple_devices_migration_blocker;
1027
1028 /*
1029 * Multiple devices migration is allowed only if all devices support P2P
1030 * migration. Single device migration is allowed regardless of P2P migration
1031 * support.
1032 */
vfio_multiple_devices_migration_is_supported(void)1033 static bool vfio_multiple_devices_migration_is_supported(void)
1034 {
1035 VFIODevice *vbasedev;
1036 unsigned int device_num = 0;
1037 bool all_support_p2p = true;
1038
1039 QLIST_FOREACH(vbasedev, &vfio_device_list, global_next) {
1040 if (vbasedev->migration) {
1041 device_num++;
1042
1043 if (!(vbasedev->migration->mig_flags & VFIO_MIGRATION_P2P)) {
1044 all_support_p2p = false;
1045 }
1046 }
1047 }
1048
1049 return all_support_p2p || device_num <= 1;
1050 }
1051
vfio_block_multiple_devices_migration(VFIODevice * vbasedev,Error ** errp)1052 static int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp)
1053 {
1054 if (vfio_multiple_devices_migration_is_supported()) {
1055 return 0;
1056 }
1057
1058 if (vbasedev->enable_migration == ON_OFF_AUTO_ON) {
1059 error_setg(errp, "Multiple VFIO devices migration is supported only if "
1060 "all of them support P2P migration");
1061 return -EINVAL;
1062 }
1063
1064 if (multiple_devices_migration_blocker) {
1065 return 0;
1066 }
1067
1068 error_setg(&multiple_devices_migration_blocker,
1069 "Multiple VFIO devices migration is supported only if all of "
1070 "them support P2P migration");
1071 return migrate_add_blocker_normal(&multiple_devices_migration_blocker,
1072 errp);
1073 }
1074
vfio_unblock_multiple_devices_migration(void)1075 static void vfio_unblock_multiple_devices_migration(void)
1076 {
1077 if (!multiple_devices_migration_blocker ||
1078 !vfio_multiple_devices_migration_is_supported()) {
1079 return;
1080 }
1081
1082 migrate_del_blocker(&multiple_devices_migration_blocker);
1083 }
1084
vfio_migration_deinit(VFIODevice * vbasedev)1085 static void vfio_migration_deinit(VFIODevice *vbasedev)
1086 {
1087 VFIOMigration *migration = vbasedev->migration;
1088
1089 migration_remove_notifier(&migration->migration_state);
1090 qemu_del_vm_change_state_handler(migration->vm_state);
1091 unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev);
1092 vfio_migration_free(vbasedev);
1093 vfio_unblock_multiple_devices_migration();
1094 }
1095
vfio_block_migration(VFIODevice * vbasedev,Error * err,Error ** errp)1096 static int vfio_block_migration(VFIODevice *vbasedev, Error *err, Error **errp)
1097 {
1098 if (vbasedev->enable_migration == ON_OFF_AUTO_ON) {
1099 error_propagate(errp, err);
1100 return -EINVAL;
1101 }
1102
1103 vbasedev->migration_blocker = error_copy(err);
1104 error_free(err);
1105
1106 return migrate_add_blocker_normal(&vbasedev->migration_blocker, errp);
1107 }
1108
1109 /* ---------------------------------------------------------------------- */
1110
vfio_migration_bytes_transferred(void)1111 int64_t vfio_migration_bytes_transferred(void)
1112 {
1113 return MIN(qatomic_read(&bytes_transferred), INT64_MAX);
1114 }
1115
vfio_migration_reset_bytes_transferred(void)1116 void vfio_migration_reset_bytes_transferred(void)
1117 {
1118 qatomic_set(&bytes_transferred, 0);
1119 }
1120
vfio_migration_add_bytes_transferred(unsigned long val)1121 void vfio_migration_add_bytes_transferred(unsigned long val)
1122 {
1123 qatomic_add(&bytes_transferred, val);
1124 }
1125
vfio_migration_active(void)1126 bool vfio_migration_active(void)
1127 {
1128 VFIODevice *vbasedev;
1129
1130 if (QLIST_EMPTY(&vfio_device_list)) {
1131 return false;
1132 }
1133
1134 QLIST_FOREACH(vbasedev, &vfio_device_list, global_next) {
1135 if (vbasedev->migration_blocker) {
1136 return false;
1137 }
1138 }
1139 return true;
1140 }
1141
vfio_viommu_preset(VFIODevice * vbasedev)1142 static bool vfio_viommu_preset(VFIODevice *vbasedev)
1143 {
1144 return vbasedev->bcontainer->space->as != &address_space_memory;
1145 }
1146
1147 /*
1148 * Return true when either migration initialized or blocker registered.
1149 * Currently only return false when adding blocker fails which will
1150 * de-register vfio device.
1151 */
vfio_migration_realize(VFIODevice * vbasedev,Error ** errp)1152 bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
1153 {
1154 Error *err = NULL;
1155 int ret;
1156
1157 if (vbasedev->enable_migration == ON_OFF_AUTO_OFF) {
1158 error_setg(&err, "%s: Migration is disabled for VFIO device",
1159 vbasedev->name);
1160 return !vfio_block_migration(vbasedev, err, errp);
1161 }
1162
1163 ret = vfio_migration_init(vbasedev);
1164 if (ret) {
1165 if (ret == -ENOTTY) {
1166 error_setg(&err, "%s: VFIO migration is not supported in kernel",
1167 vbasedev->name);
1168 } else {
1169 error_setg(&err,
1170 "%s: Migration couldn't be initialized for VFIO device, "
1171 "err: %d (%s)",
1172 vbasedev->name, ret, strerror(-ret));
1173 }
1174
1175 return !vfio_block_migration(vbasedev, err, errp);
1176 }
1177
1178 if ((!vbasedev->dirty_pages_supported ||
1179 vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
1180 !vbasedev->iommu_dirty_tracking) {
1181 if (vbasedev->enable_migration == ON_OFF_AUTO_AUTO) {
1182 error_setg(&err,
1183 "%s: VFIO device doesn't support device and "
1184 "IOMMU dirty tracking", vbasedev->name);
1185 goto add_blocker;
1186 }
1187
1188 warn_report("%s: VFIO device doesn't support device and "
1189 "IOMMU dirty tracking", vbasedev->name);
1190 }
1191
1192 ret = vfio_block_multiple_devices_migration(vbasedev, errp);
1193 if (ret) {
1194 goto out_deinit;
1195 }
1196
1197 if (vfio_viommu_preset(vbasedev)) {
1198 error_setg(&err, "%s: Migration is currently not supported "
1199 "with vIOMMU enabled", vbasedev->name);
1200 goto add_blocker;
1201 }
1202
1203 trace_vfio_migration_realize(vbasedev->name);
1204 return true;
1205
1206 add_blocker:
1207 ret = vfio_block_migration(vbasedev, err, errp);
1208 out_deinit:
1209 if (ret) {
1210 vfio_migration_deinit(vbasedev);
1211 }
1212 return !ret;
1213 }
1214
vfio_migration_exit(VFIODevice * vbasedev)1215 void vfio_migration_exit(VFIODevice *vbasedev)
1216 {
1217 if (vbasedev->migration) {
1218 vfio_migration_deinit(vbasedev);
1219 }
1220
1221 migrate_del_blocker(&vbasedev->migration_blocker);
1222 }
1223
vfio_device_state_is_running(VFIODevice * vbasedev)1224 bool vfio_device_state_is_running(VFIODevice *vbasedev)
1225 {
1226 VFIOMigration *migration = vbasedev->migration;
1227
1228 return migration->device_state == VFIO_DEVICE_STATE_RUNNING ||
1229 migration->device_state == VFIO_DEVICE_STATE_RUNNING_P2P;
1230 }
1231
vfio_device_state_is_precopy(VFIODevice * vbasedev)1232 bool vfio_device_state_is_precopy(VFIODevice *vbasedev)
1233 {
1234 VFIOMigration *migration = vbasedev->migration;
1235
1236 return migration->device_state == VFIO_DEVICE_STATE_PRE_COPY ||
1237 migration->device_state == VFIO_DEVICE_STATE_PRE_COPY_P2P;
1238 }
1239