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/misc.h"
21 #include "migration/savevm.h"
22 #include "migration/vmstate.h"
23 #include "migration/qemu-file.h"
24 #include "migration/register.h"
25 #include "migration/blocker.h"
26 #include "qapi/error.h"
27 #include "qapi/qapi-events-vfio.h"
28 #include "exec/ramlist.h"
29 #include "exec/ram_addr.h"
30 #include "pci.h"
31 #include "trace.h"
32 #include "hw/hw.h"
33
34 /*
35 * Flags to be used as unique delimiters for VFIO devices in the migration
36 * stream. These flags are composed as:
37 * 0xffffffff => MSB 32-bit all 1s
38 * 0xef10 => Magic ID, represents emulated (virtual) function IO
39 * 0x0000 => 16-bits reserved for flags
40 *
41 * The beginning of state information is marked by _DEV_CONFIG_STATE,
42 * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a
43 * certain state information is marked by _END_OF_STATE.
44 */
45 #define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL)
46 #define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL)
47 #define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL)
48 #define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL)
49 #define VFIO_MIG_FLAG_DEV_INIT_DATA_SENT (0xffffffffef100005ULL)
50
51 /*
52 * This is an arbitrary size based on migration of mlx5 devices, where typically
53 * total device migration size is on the order of 100s of MB. Testing with
54 * larger values, e.g. 128MB and 1GB, did not show a performance improvement.
55 */
56 #define VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE (1 * MiB)
57
58 static int64_t bytes_transferred;
59
mig_state_to_str(enum vfio_device_mig_state state)60 static const char *mig_state_to_str(enum vfio_device_mig_state state)
61 {
62 switch (state) {
63 case VFIO_DEVICE_STATE_ERROR:
64 return "ERROR";
65 case VFIO_DEVICE_STATE_STOP:
66 return "STOP";
67 case VFIO_DEVICE_STATE_RUNNING:
68 return "RUNNING";
69 case VFIO_DEVICE_STATE_STOP_COPY:
70 return "STOP_COPY";
71 case VFIO_DEVICE_STATE_RESUMING:
72 return "RESUMING";
73 case VFIO_DEVICE_STATE_RUNNING_P2P:
74 return "RUNNING_P2P";
75 case VFIO_DEVICE_STATE_PRE_COPY:
76 return "PRE_COPY";
77 case VFIO_DEVICE_STATE_PRE_COPY_P2P:
78 return "PRE_COPY_P2P";
79 default:
80 return "UNKNOWN STATE";
81 }
82 }
83
84 static VfioMigrationState
mig_state_to_qapi_state(enum vfio_device_mig_state state)85 mig_state_to_qapi_state(enum vfio_device_mig_state state)
86 {
87 switch (state) {
88 case VFIO_DEVICE_STATE_STOP:
89 return QAPI_VFIO_MIGRATION_STATE_STOP;
90 case VFIO_DEVICE_STATE_RUNNING:
91 return QAPI_VFIO_MIGRATION_STATE_RUNNING;
92 case VFIO_DEVICE_STATE_STOP_COPY:
93 return QAPI_VFIO_MIGRATION_STATE_STOP_COPY;
94 case VFIO_DEVICE_STATE_RESUMING:
95 return QAPI_VFIO_MIGRATION_STATE_RESUMING;
96 case VFIO_DEVICE_STATE_RUNNING_P2P:
97 return QAPI_VFIO_MIGRATION_STATE_RUNNING_P2P;
98 case VFIO_DEVICE_STATE_PRE_COPY:
99 return QAPI_VFIO_MIGRATION_STATE_PRE_COPY;
100 case VFIO_DEVICE_STATE_PRE_COPY_P2P:
101 return QAPI_VFIO_MIGRATION_STATE_PRE_COPY_P2P;
102 default:
103 g_assert_not_reached();
104 }
105 }
106
vfio_migration_send_event(VFIODevice * vbasedev)107 static void vfio_migration_send_event(VFIODevice *vbasedev)
108 {
109 VFIOMigration *migration = vbasedev->migration;
110 DeviceState *dev = vbasedev->dev;
111 g_autofree char *qom_path = NULL;
112 Object *obj;
113
114 if (!vbasedev->migration_events) {
115 return;
116 }
117
118 g_assert(vbasedev->ops->vfio_get_object);
119 obj = vbasedev->ops->vfio_get_object(vbasedev);
120 g_assert(obj);
121 qom_path = object_get_canonical_path(obj);
122
123 qapi_event_send_vfio_migration(
124 dev->id, qom_path, mig_state_to_qapi_state(migration->device_state));
125 }
126
vfio_migration_set_device_state(VFIODevice * vbasedev,enum vfio_device_mig_state state)127 static void vfio_migration_set_device_state(VFIODevice *vbasedev,
128 enum vfio_device_mig_state state)
129 {
130 VFIOMigration *migration = vbasedev->migration;
131
132 trace_vfio_migration_set_device_state(vbasedev->name,
133 mig_state_to_str(state));
134
135 migration->device_state = state;
136 vfio_migration_send_event(vbasedev);
137 }
138
vfio_migration_set_state(VFIODevice * vbasedev,enum vfio_device_mig_state new_state,enum vfio_device_mig_state recover_state,Error ** errp)139 static int vfio_migration_set_state(VFIODevice *vbasedev,
140 enum vfio_device_mig_state new_state,
141 enum vfio_device_mig_state recover_state,
142 Error **errp)
143 {
144 VFIOMigration *migration = vbasedev->migration;
145 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
146 sizeof(struct vfio_device_feature_mig_state),
147 sizeof(uint64_t))] = {};
148 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
149 struct vfio_device_feature_mig_state *mig_state =
150 (struct vfio_device_feature_mig_state *)feature->data;
151 int ret;
152 g_autofree char *error_prefix =
153 g_strdup_printf("%s: Failed setting device state to %s.",
154 vbasedev->name, mig_state_to_str(new_state));
155
156 trace_vfio_migration_set_state(vbasedev->name, mig_state_to_str(new_state),
157 mig_state_to_str(recover_state));
158
159 if (new_state == migration->device_state) {
160 return 0;
161 }
162
163 feature->argsz = sizeof(buf);
164 feature->flags =
165 VFIO_DEVICE_FEATURE_SET | VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE;
166 mig_state->device_state = new_state;
167 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
168 /* Try to set the device in some good state */
169 ret = -errno;
170
171 if (recover_state == VFIO_DEVICE_STATE_ERROR) {
172 error_setg_errno(errp, errno,
173 "%s Recover state is ERROR. Resetting device",
174 error_prefix);
175
176 goto reset_device;
177 }
178
179 error_setg_errno(errp, errno,
180 "%s Setting device in recover state %s",
181 error_prefix, mig_state_to_str(recover_state));
182
183 mig_state->device_state = recover_state;
184 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
185 ret = -errno;
186 /*
187 * If setting the device in recover state fails, report
188 * the error here and propagate the first error.
189 */
190 error_report(
191 "%s: Failed setting device in recover state, err: %s. Resetting device",
192 vbasedev->name, strerror(errno));
193
194 goto reset_device;
195 }
196
197 vfio_migration_set_device_state(vbasedev, recover_state);
198
199 return ret;
200 }
201
202 vfio_migration_set_device_state(vbasedev, new_state);
203 if (mig_state->data_fd != -1) {
204 if (migration->data_fd != -1) {
205 /*
206 * This can happen if the device is asynchronously reset and
207 * terminates a data transfer.
208 */
209 error_setg(errp, "%s: data_fd out of sync", vbasedev->name);
210 close(mig_state->data_fd);
211
212 return -EBADF;
213 }
214
215 migration->data_fd = mig_state->data_fd;
216 }
217
218 return 0;
219
220 reset_device:
221 if (ioctl(vbasedev->fd, VFIO_DEVICE_RESET)) {
222 hw_error("%s: Failed resetting device, err: %s", vbasedev->name,
223 strerror(errno));
224 }
225
226 vfio_migration_set_device_state(vbasedev, VFIO_DEVICE_STATE_RUNNING);
227
228 return ret;
229 }
230
231 /*
232 * Some device state transitions require resetting the device if they fail.
233 * This function sets the device in new_state and resets the device if that
234 * fails. Reset is done by using ERROR as the recover state.
235 */
236 static int
vfio_migration_set_state_or_reset(VFIODevice * vbasedev,enum vfio_device_mig_state new_state,Error ** errp)237 vfio_migration_set_state_or_reset(VFIODevice *vbasedev,
238 enum vfio_device_mig_state new_state,
239 Error **errp)
240 {
241 return vfio_migration_set_state(vbasedev, new_state,
242 VFIO_DEVICE_STATE_ERROR, errp);
243 }
244
vfio_load_buffer(QEMUFile * f,VFIODevice * vbasedev,uint64_t data_size)245 static int vfio_load_buffer(QEMUFile *f, VFIODevice *vbasedev,
246 uint64_t data_size)
247 {
248 VFIOMigration *migration = vbasedev->migration;
249 int ret;
250
251 ret = qemu_file_get_to_fd(f, migration->data_fd, data_size);
252 trace_vfio_load_state_device_data(vbasedev->name, data_size, ret);
253
254 return ret;
255 }
256
vfio_save_device_config_state(QEMUFile * f,void * opaque,Error ** errp)257 static int vfio_save_device_config_state(QEMUFile *f, void *opaque,
258 Error **errp)
259 {
260 VFIODevice *vbasedev = opaque;
261 int ret;
262
263 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE);
264
265 if (vbasedev->ops && vbasedev->ops->vfio_save_config) {
266 ret = vbasedev->ops->vfio_save_config(vbasedev, f, errp);
267 if (ret) {
268 return ret;
269 }
270 }
271
272 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
273
274 trace_vfio_save_device_config_state(vbasedev->name);
275
276 ret = qemu_file_get_error(f);
277 if (ret < 0) {
278 error_setg_errno(errp, -ret, "Failed to save state");
279 }
280 return ret;
281 }
282
vfio_load_device_config_state(QEMUFile * f,void * opaque)283 static int vfio_load_device_config_state(QEMUFile *f, void *opaque)
284 {
285 VFIODevice *vbasedev = opaque;
286 uint64_t data;
287
288 if (vbasedev->ops && vbasedev->ops->vfio_load_config) {
289 int ret;
290
291 ret = vbasedev->ops->vfio_load_config(vbasedev, f);
292 if (ret) {
293 error_report("%s: Failed to load device config space",
294 vbasedev->name);
295 return ret;
296 }
297 }
298
299 data = qemu_get_be64(f);
300 if (data != VFIO_MIG_FLAG_END_OF_STATE) {
301 error_report("%s: Failed loading device config space, "
302 "end flag incorrect 0x%"PRIx64, vbasedev->name, data);
303 return -EINVAL;
304 }
305
306 trace_vfio_load_device_config_state(vbasedev->name);
307 return qemu_file_get_error(f);
308 }
309
vfio_migration_cleanup(VFIODevice * vbasedev)310 static void vfio_migration_cleanup(VFIODevice *vbasedev)
311 {
312 VFIOMigration *migration = vbasedev->migration;
313
314 close(migration->data_fd);
315 migration->data_fd = -1;
316 }
317
vfio_query_stop_copy_size(VFIODevice * vbasedev,uint64_t * stop_copy_size)318 static int vfio_query_stop_copy_size(VFIODevice *vbasedev,
319 uint64_t *stop_copy_size)
320 {
321 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
322 sizeof(struct vfio_device_feature_mig_data_size),
323 sizeof(uint64_t))] = {};
324 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
325 struct vfio_device_feature_mig_data_size *mig_data_size =
326 (struct vfio_device_feature_mig_data_size *)feature->data;
327
328 feature->argsz = sizeof(buf);
329 feature->flags =
330 VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIG_DATA_SIZE;
331
332 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
333 return -errno;
334 }
335
336 *stop_copy_size = mig_data_size->stop_copy_length;
337
338 return 0;
339 }
340
vfio_query_precopy_size(VFIOMigration * migration)341 static int vfio_query_precopy_size(VFIOMigration *migration)
342 {
343 struct vfio_precopy_info precopy = {
344 .argsz = sizeof(precopy),
345 };
346
347 migration->precopy_init_size = 0;
348 migration->precopy_dirty_size = 0;
349
350 if (ioctl(migration->data_fd, VFIO_MIG_GET_PRECOPY_INFO, &precopy)) {
351 return -errno;
352 }
353
354 migration->precopy_init_size = precopy.initial_bytes;
355 migration->precopy_dirty_size = precopy.dirty_bytes;
356
357 return 0;
358 }
359
360 /* Returns the size of saved data on success and -errno on error */
vfio_save_block(QEMUFile * f,VFIOMigration * migration)361 static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration)
362 {
363 ssize_t data_size;
364
365 data_size = read(migration->data_fd, migration->data_buffer,
366 migration->data_buffer_size);
367 if (data_size < 0) {
368 /*
369 * Pre-copy emptied all the device state for now. For more information,
370 * please refer to the Linux kernel VFIO uAPI.
371 */
372 if (errno == ENOMSG) {
373 return 0;
374 }
375
376 return -errno;
377 }
378 if (data_size == 0) {
379 return 0;
380 }
381
382 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
383 qemu_put_be64(f, data_size);
384 qemu_put_buffer(f, migration->data_buffer, data_size);
385 bytes_transferred += data_size;
386
387 trace_vfio_save_block(migration->vbasedev->name, data_size);
388
389 return qemu_file_get_error(f) ?: data_size;
390 }
391
vfio_update_estimated_pending_data(VFIOMigration * migration,uint64_t data_size)392 static void vfio_update_estimated_pending_data(VFIOMigration *migration,
393 uint64_t data_size)
394 {
395 if (!data_size) {
396 /*
397 * Pre-copy emptied all the device state for now, update estimated sizes
398 * accordingly.
399 */
400 migration->precopy_init_size = 0;
401 migration->precopy_dirty_size = 0;
402
403 return;
404 }
405
406 if (migration->precopy_init_size) {
407 uint64_t init_size = MIN(migration->precopy_init_size, data_size);
408
409 migration->precopy_init_size -= init_size;
410 data_size -= init_size;
411 }
412
413 migration->precopy_dirty_size -= MIN(migration->precopy_dirty_size,
414 data_size);
415 }
416
vfio_precopy_supported(VFIODevice * vbasedev)417 static bool vfio_precopy_supported(VFIODevice *vbasedev)
418 {
419 VFIOMigration *migration = vbasedev->migration;
420
421 return migration->mig_flags & VFIO_MIGRATION_PRE_COPY;
422 }
423
424 /* ---------------------------------------------------------------------- */
425
vfio_save_prepare(void * opaque,Error ** errp)426 static int vfio_save_prepare(void *opaque, Error **errp)
427 {
428 VFIODevice *vbasedev = opaque;
429
430 /*
431 * Snapshot doesn't use postcopy nor background snapshot, so allow snapshot
432 * even if they are on.
433 */
434 if (runstate_check(RUN_STATE_SAVE_VM)) {
435 return 0;
436 }
437
438 if (migrate_postcopy_ram()) {
439 error_setg(
440 errp, "%s: VFIO migration is not supported with postcopy migration",
441 vbasedev->name);
442 return -EOPNOTSUPP;
443 }
444
445 if (migrate_background_snapshot()) {
446 error_setg(
447 errp,
448 "%s: VFIO migration is not supported with background snapshot",
449 vbasedev->name);
450 return -EOPNOTSUPP;
451 }
452
453 return 0;
454 }
455
vfio_save_setup(QEMUFile * f,void * opaque,Error ** errp)456 static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp)
457 {
458 VFIODevice *vbasedev = opaque;
459 VFIOMigration *migration = vbasedev->migration;
460 uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
461 int ret;
462
463 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
464
465 vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
466 migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
467 stop_copy_size);
468 migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
469 if (!migration->data_buffer) {
470 error_setg(errp, "%s: Failed to allocate migration data buffer",
471 vbasedev->name);
472 return -ENOMEM;
473 }
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 /*
517 * Changing device state from STOP_COPY to STOP can take time. Do it here,
518 * after migration has completed, so it won't increase downtime.
519 */
520 if (migration->device_state == VFIO_DEVICE_STATE_STOP_COPY) {
521 ret = vfio_migration_set_state_or_reset(vbasedev,
522 VFIO_DEVICE_STATE_STOP,
523 &local_err);
524 if (ret) {
525 error_report_err(local_err);
526 }
527 }
528
529 g_free(migration->data_buffer);
530 migration->data_buffer = NULL;
531 migration->precopy_init_size = 0;
532 migration->precopy_dirty_size = 0;
533 migration->initial_data_sent = false;
534 vfio_migration_cleanup(vbasedev);
535 trace_vfio_save_cleanup(vbasedev->name);
536 }
537
vfio_state_pending_estimate(void * opaque,uint64_t * must_precopy,uint64_t * can_postcopy)538 static void vfio_state_pending_estimate(void *opaque, uint64_t *must_precopy,
539 uint64_t *can_postcopy)
540 {
541 VFIODevice *vbasedev = opaque;
542 VFIOMigration *migration = vbasedev->migration;
543
544 if (!vfio_device_state_is_precopy(vbasedev)) {
545 return;
546 }
547
548 *must_precopy +=
549 migration->precopy_init_size + migration->precopy_dirty_size;
550
551 trace_vfio_state_pending_estimate(vbasedev->name, *must_precopy,
552 *can_postcopy,
553 migration->precopy_init_size,
554 migration->precopy_dirty_size);
555 }
556
557 /*
558 * Migration size of VFIO devices can be as little as a few KBs or as big as
559 * many GBs. This value should be big enough to cover the worst case.
560 */
561 #define VFIO_MIG_STOP_COPY_SIZE (100 * GiB)
562
vfio_state_pending_exact(void * opaque,uint64_t * must_precopy,uint64_t * can_postcopy)563 static void vfio_state_pending_exact(void *opaque, uint64_t *must_precopy,
564 uint64_t *can_postcopy)
565 {
566 VFIODevice *vbasedev = opaque;
567 VFIOMigration *migration = vbasedev->migration;
568 uint64_t stop_copy_size = VFIO_MIG_STOP_COPY_SIZE;
569
570 /*
571 * If getting pending migration size fails, VFIO_MIG_STOP_COPY_SIZE is
572 * reported so downtime limit won't be violated.
573 */
574 vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
575 *must_precopy += stop_copy_size;
576
577 if (vfio_device_state_is_precopy(vbasedev)) {
578 vfio_query_precopy_size(migration);
579 }
580
581 trace_vfio_state_pending_exact(vbasedev->name, *must_precopy, *can_postcopy,
582 stop_copy_size, migration->precopy_init_size,
583 migration->precopy_dirty_size);
584 }
585
vfio_is_active_iterate(void * opaque)586 static bool vfio_is_active_iterate(void *opaque)
587 {
588 VFIODevice *vbasedev = opaque;
589
590 return vfio_device_state_is_precopy(vbasedev);
591 }
592
593 /*
594 * Note about migration rate limiting: VFIO migration buffer size is currently
595 * limited to 1MB, so there is no need to check if migration rate exceeded (as
596 * in the worst case it will exceed by 1MB). However, if the buffer size is
597 * later changed to a bigger value, migration rate should be enforced here.
598 */
vfio_save_iterate(QEMUFile * f,void * opaque)599 static int vfio_save_iterate(QEMUFile *f, void *opaque)
600 {
601 VFIODevice *vbasedev = opaque;
602 VFIOMigration *migration = vbasedev->migration;
603 ssize_t data_size;
604
605 data_size = vfio_save_block(f, migration);
606 if (data_size < 0) {
607 return data_size;
608 }
609
610 vfio_update_estimated_pending_data(migration, data_size);
611
612 if (migrate_switchover_ack() && !migration->precopy_init_size &&
613 !migration->initial_data_sent) {
614 qemu_put_be64(f, VFIO_MIG_FLAG_DEV_INIT_DATA_SENT);
615 migration->initial_data_sent = true;
616 } else {
617 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
618 }
619
620 trace_vfio_save_iterate(vbasedev->name, migration->precopy_init_size,
621 migration->precopy_dirty_size);
622
623 return !migration->precopy_init_size && !migration->precopy_dirty_size;
624 }
625
vfio_save_complete_precopy(QEMUFile * f,void * opaque)626 static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
627 {
628 VFIODevice *vbasedev = opaque;
629 ssize_t data_size;
630 int ret;
631 Error *local_err = NULL;
632
633 /* We reach here with device state STOP or STOP_COPY only */
634 ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY,
635 VFIO_DEVICE_STATE_STOP, &local_err);
636 if (ret) {
637 error_report_err(local_err);
638 return ret;
639 }
640
641 do {
642 data_size = vfio_save_block(f, vbasedev->migration);
643 if (data_size < 0) {
644 return data_size;
645 }
646 } while (data_size);
647
648 qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
649 ret = qemu_file_get_error(f);
650
651 trace_vfio_save_complete_precopy(vbasedev->name, ret);
652
653 return ret;
654 }
655
vfio_save_state(QEMUFile * f,void * opaque)656 static void vfio_save_state(QEMUFile *f, void *opaque)
657 {
658 VFIODevice *vbasedev = opaque;
659 Error *local_err = NULL;
660 int ret;
661
662 ret = vfio_save_device_config_state(f, opaque, &local_err);
663 if (ret) {
664 error_prepend(&local_err,
665 "vfio: Failed to save device config space of %s - ",
666 vbasedev->name);
667 qemu_file_set_error_obj(f, ret, local_err);
668 }
669 }
670
vfio_load_setup(QEMUFile * f,void * opaque,Error ** errp)671 static int vfio_load_setup(QEMUFile *f, void *opaque, Error **errp)
672 {
673 VFIODevice *vbasedev = opaque;
674
675 return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
676 vbasedev->migration->device_state, errp);
677 }
678
vfio_load_cleanup(void * opaque)679 static int vfio_load_cleanup(void *opaque)
680 {
681 VFIODevice *vbasedev = opaque;
682
683 vfio_migration_cleanup(vbasedev);
684 trace_vfio_load_cleanup(vbasedev->name);
685
686 return 0;
687 }
688
vfio_load_state(QEMUFile * f,void * opaque,int version_id)689 static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
690 {
691 VFIODevice *vbasedev = opaque;
692 int ret = 0;
693 uint64_t data;
694
695 data = qemu_get_be64(f);
696 while (data != VFIO_MIG_FLAG_END_OF_STATE) {
697
698 trace_vfio_load_state(vbasedev->name, data);
699
700 switch (data) {
701 case VFIO_MIG_FLAG_DEV_CONFIG_STATE:
702 {
703 return vfio_load_device_config_state(f, opaque);
704 }
705 case VFIO_MIG_FLAG_DEV_SETUP_STATE:
706 {
707 data = qemu_get_be64(f);
708 if (data == VFIO_MIG_FLAG_END_OF_STATE) {
709 return ret;
710 } else {
711 error_report("%s: SETUP STATE: EOS not found 0x%"PRIx64,
712 vbasedev->name, data);
713 return -EINVAL;
714 }
715 break;
716 }
717 case VFIO_MIG_FLAG_DEV_DATA_STATE:
718 {
719 uint64_t data_size = qemu_get_be64(f);
720
721 if (data_size) {
722 ret = vfio_load_buffer(f, vbasedev, data_size);
723 if (ret < 0) {
724 return ret;
725 }
726 }
727 break;
728 }
729 case VFIO_MIG_FLAG_DEV_INIT_DATA_SENT:
730 {
731 if (!vfio_precopy_supported(vbasedev) ||
732 !migrate_switchover_ack()) {
733 error_report("%s: Received INIT_DATA_SENT but switchover ack "
734 "is not used", vbasedev->name);
735 return -EINVAL;
736 }
737
738 ret = qemu_loadvm_approve_switchover();
739 if (ret) {
740 error_report(
741 "%s: qemu_loadvm_approve_switchover failed, err=%d (%s)",
742 vbasedev->name, ret, strerror(-ret));
743 }
744
745 return ret;
746 }
747 default:
748 error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data);
749 return -EINVAL;
750 }
751
752 data = qemu_get_be64(f);
753 ret = qemu_file_get_error(f);
754 if (ret) {
755 return ret;
756 }
757 }
758 return ret;
759 }
760
vfio_switchover_ack_needed(void * opaque)761 static bool vfio_switchover_ack_needed(void *opaque)
762 {
763 VFIODevice *vbasedev = opaque;
764
765 return vfio_precopy_supported(vbasedev);
766 }
767
768 static const SaveVMHandlers savevm_vfio_handlers = {
769 .save_prepare = vfio_save_prepare,
770 .save_setup = vfio_save_setup,
771 .save_cleanup = vfio_save_cleanup,
772 .state_pending_estimate = vfio_state_pending_estimate,
773 .state_pending_exact = vfio_state_pending_exact,
774 .is_active_iterate = vfio_is_active_iterate,
775 .save_live_iterate = vfio_save_iterate,
776 .save_live_complete_precopy = vfio_save_complete_precopy,
777 .save_state = vfio_save_state,
778 .load_setup = vfio_load_setup,
779 .load_cleanup = vfio_load_cleanup,
780 .load_state = vfio_load_state,
781 .switchover_ack_needed = vfio_switchover_ack_needed,
782 };
783
784 /* ---------------------------------------------------------------------- */
785
vfio_vmstate_change_prepare(void * opaque,bool running,RunState state)786 static void vfio_vmstate_change_prepare(void *opaque, bool running,
787 RunState state)
788 {
789 VFIODevice *vbasedev = opaque;
790 VFIOMigration *migration = vbasedev->migration;
791 enum vfio_device_mig_state new_state;
792 Error *local_err = NULL;
793 int ret;
794
795 new_state = migration->device_state == VFIO_DEVICE_STATE_PRE_COPY ?
796 VFIO_DEVICE_STATE_PRE_COPY_P2P :
797 VFIO_DEVICE_STATE_RUNNING_P2P;
798
799 ret = vfio_migration_set_state_or_reset(vbasedev, new_state, &local_err);
800 if (ret) {
801 /*
802 * Migration should be aborted in this case, but vm_state_notify()
803 * currently does not support reporting failures.
804 */
805 migration_file_set_error(ret, local_err);
806 }
807
808 trace_vfio_vmstate_change_prepare(vbasedev->name, running,
809 RunState_str(state),
810 mig_state_to_str(new_state));
811 }
812
vfio_vmstate_change(void * opaque,bool running,RunState state)813 static void vfio_vmstate_change(void *opaque, bool running, RunState state)
814 {
815 VFIODevice *vbasedev = opaque;
816 enum vfio_device_mig_state new_state;
817 Error *local_err = NULL;
818 int ret;
819
820 if (running) {
821 new_state = VFIO_DEVICE_STATE_RUNNING;
822 } else {
823 new_state =
824 (vfio_device_state_is_precopy(vbasedev) &&
825 (state == RUN_STATE_FINISH_MIGRATE || state == RUN_STATE_PAUSED)) ?
826 VFIO_DEVICE_STATE_STOP_COPY :
827 VFIO_DEVICE_STATE_STOP;
828 }
829
830 ret = vfio_migration_set_state_or_reset(vbasedev, new_state, &local_err);
831 if (ret) {
832 /*
833 * Migration should be aborted in this case, but vm_state_notify()
834 * currently does not support reporting failures.
835 */
836 migration_file_set_error(ret, local_err);
837 }
838
839 trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state),
840 mig_state_to_str(new_state));
841 }
842
vfio_migration_state_notifier(NotifierWithReturn * notifier,MigrationEvent * e,Error ** errp)843 static int vfio_migration_state_notifier(NotifierWithReturn *notifier,
844 MigrationEvent *e, Error **errp)
845 {
846 VFIOMigration *migration = container_of(notifier, VFIOMigration,
847 migration_state);
848 VFIODevice *vbasedev = migration->vbasedev;
849 Error *local_err = NULL;
850 int ret;
851
852 trace_vfio_migration_state_notifier(vbasedev->name, e->type);
853
854 if (e->type == MIG_EVENT_PRECOPY_FAILED) {
855 /*
856 * MigrationNotifyFunc may not return an error code and an Error
857 * object for MIG_EVENT_PRECOPY_FAILED. Hence, report the error
858 * locally and ignore the errp argument.
859 */
860 ret = vfio_migration_set_state_or_reset(vbasedev,
861 VFIO_DEVICE_STATE_RUNNING,
862 &local_err);
863 if (ret) {
864 error_report_err(local_err);
865 }
866 }
867 return 0;
868 }
869
vfio_migration_free(VFIODevice * vbasedev)870 static void vfio_migration_free(VFIODevice *vbasedev)
871 {
872 g_free(vbasedev->migration);
873 vbasedev->migration = NULL;
874 }
875
vfio_migration_query_flags(VFIODevice * vbasedev,uint64_t * mig_flags)876 static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags)
877 {
878 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
879 sizeof(struct vfio_device_feature_migration),
880 sizeof(uint64_t))] = {};
881 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
882 struct vfio_device_feature_migration *mig =
883 (struct vfio_device_feature_migration *)feature->data;
884
885 feature->argsz = sizeof(buf);
886 feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION;
887 if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
888 return -errno;
889 }
890
891 *mig_flags = mig->flags;
892
893 return 0;
894 }
895
vfio_dma_logging_supported(VFIODevice * vbasedev)896 static bool vfio_dma_logging_supported(VFIODevice *vbasedev)
897 {
898 uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature),
899 sizeof(uint64_t))] = {};
900 struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
901
902 feature->argsz = sizeof(buf);
903 feature->flags = VFIO_DEVICE_FEATURE_PROBE |
904 VFIO_DEVICE_FEATURE_DMA_LOGGING_START;
905
906 return !ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature);
907 }
908
vfio_migration_init(VFIODevice * vbasedev)909 static int vfio_migration_init(VFIODevice *vbasedev)
910 {
911 int ret;
912 Object *obj;
913 VFIOMigration *migration;
914 char id[256] = "";
915 g_autofree char *path = NULL, *oid = NULL;
916 uint64_t mig_flags = 0;
917 VMChangeStateHandler *prepare_cb;
918
919 if (!vbasedev->ops->vfio_get_object) {
920 return -EINVAL;
921 }
922
923 obj = vbasedev->ops->vfio_get_object(vbasedev);
924 if (!obj) {
925 return -EINVAL;
926 }
927
928 ret = vfio_migration_query_flags(vbasedev, &mig_flags);
929 if (ret) {
930 return ret;
931 }
932
933 /* Basic migration functionality must be supported */
934 if (!(mig_flags & VFIO_MIGRATION_STOP_COPY)) {
935 return -EOPNOTSUPP;
936 }
937
938 vbasedev->migration = g_new0(VFIOMigration, 1);
939 migration = vbasedev->migration;
940 migration->vbasedev = vbasedev;
941 migration->device_state = VFIO_DEVICE_STATE_RUNNING;
942 migration->data_fd = -1;
943 migration->mig_flags = mig_flags;
944
945 vbasedev->dirty_pages_supported = vfio_dma_logging_supported(vbasedev);
946
947 oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj)));
948 if (oid) {
949 path = g_strdup_printf("%s/vfio", oid);
950 } else {
951 path = g_strdup("vfio");
952 }
953 strpadcpy(id, sizeof(id), path, '\0');
954
955 register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers,
956 vbasedev);
957
958 prepare_cb = migration->mig_flags & VFIO_MIGRATION_P2P ?
959 vfio_vmstate_change_prepare :
960 NULL;
961 migration->vm_state = qdev_add_vm_change_state_handler_full(
962 vbasedev->dev, vfio_vmstate_change, prepare_cb, vbasedev);
963 migration_add_notifier(&migration->migration_state,
964 vfio_migration_state_notifier);
965
966 return 0;
967 }
968
vfio_migration_deinit(VFIODevice * vbasedev)969 static void vfio_migration_deinit(VFIODevice *vbasedev)
970 {
971 VFIOMigration *migration = vbasedev->migration;
972
973 migration_remove_notifier(&migration->migration_state);
974 qemu_del_vm_change_state_handler(migration->vm_state);
975 unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev);
976 vfio_migration_free(vbasedev);
977 vfio_unblock_multiple_devices_migration();
978 }
979
vfio_block_migration(VFIODevice * vbasedev,Error * err,Error ** errp)980 static int vfio_block_migration(VFIODevice *vbasedev, Error *err, Error **errp)
981 {
982 if (vbasedev->enable_migration == ON_OFF_AUTO_ON) {
983 error_propagate(errp, err);
984 return -EINVAL;
985 }
986
987 vbasedev->migration_blocker = error_copy(err);
988 error_free(err);
989
990 return migrate_add_blocker_normal(&vbasedev->migration_blocker, errp);
991 }
992
993 /* ---------------------------------------------------------------------- */
994
vfio_mig_bytes_transferred(void)995 int64_t vfio_mig_bytes_transferred(void)
996 {
997 return bytes_transferred;
998 }
999
vfio_reset_bytes_transferred(void)1000 void vfio_reset_bytes_transferred(void)
1001 {
1002 bytes_transferred = 0;
1003 }
1004
1005 /*
1006 * Return true when either migration initialized or blocker registered.
1007 * Currently only return false when adding blocker fails which will
1008 * de-register vfio device.
1009 */
vfio_migration_realize(VFIODevice * vbasedev,Error ** errp)1010 bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
1011 {
1012 Error *err = NULL;
1013 int ret;
1014
1015 if (vbasedev->enable_migration == ON_OFF_AUTO_OFF) {
1016 error_setg(&err, "%s: Migration is disabled for VFIO device",
1017 vbasedev->name);
1018 return !vfio_block_migration(vbasedev, err, errp);
1019 }
1020
1021 ret = vfio_migration_init(vbasedev);
1022 if (ret) {
1023 if (ret == -ENOTTY) {
1024 error_setg(&err, "%s: VFIO migration is not supported in kernel",
1025 vbasedev->name);
1026 } else {
1027 error_setg(&err,
1028 "%s: Migration couldn't be initialized for VFIO device, "
1029 "err: %d (%s)",
1030 vbasedev->name, ret, strerror(-ret));
1031 }
1032
1033 return !vfio_block_migration(vbasedev, err, errp);
1034 }
1035
1036 if ((!vbasedev->dirty_pages_supported ||
1037 vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
1038 !vbasedev->iommu_dirty_tracking) {
1039 if (vbasedev->enable_migration == ON_OFF_AUTO_AUTO) {
1040 error_setg(&err,
1041 "%s: VFIO device doesn't support device and "
1042 "IOMMU dirty tracking", vbasedev->name);
1043 goto add_blocker;
1044 }
1045
1046 warn_report("%s: VFIO device doesn't support device and "
1047 "IOMMU dirty tracking", vbasedev->name);
1048 }
1049
1050 ret = vfio_block_multiple_devices_migration(vbasedev, errp);
1051 if (ret) {
1052 goto out_deinit;
1053 }
1054
1055 if (vfio_viommu_preset(vbasedev)) {
1056 error_setg(&err, "%s: Migration is currently not supported "
1057 "with vIOMMU enabled", vbasedev->name);
1058 goto add_blocker;
1059 }
1060
1061 trace_vfio_migration_realize(vbasedev->name);
1062 return true;
1063
1064 add_blocker:
1065 ret = vfio_block_migration(vbasedev, err, errp);
1066 out_deinit:
1067 if (ret) {
1068 vfio_migration_deinit(vbasedev);
1069 }
1070 return !ret;
1071 }
1072
vfio_migration_exit(VFIODevice * vbasedev)1073 void vfio_migration_exit(VFIODevice *vbasedev)
1074 {
1075 if (vbasedev->migration) {
1076 vfio_migration_deinit(vbasedev);
1077 }
1078
1079 migrate_del_blocker(&vbasedev->migration_blocker);
1080 }
1081