xref: /linux/drivers/vfio/pci/xe/main.c (revision d30c1683aaecb93d2ab95685dc4300a33d3cea7a) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright © 2025 Intel Corporation
4  */
5 
6 #include <linux/anon_inodes.h>
7 #include <linux/delay.h>
8 #include <linux/file.h>
9 #include <linux/module.h>
10 #include <linux/pci.h>
11 #include <linux/sizes.h>
12 #include <linux/types.h>
13 #include <linux/vfio.h>
14 #include <linux/vfio_pci_core.h>
15 
16 #include <drm/intel/xe_sriov_vfio.h>
17 #include <drm/intel/pciids.h>
18 
19 struct xe_vfio_pci_migration_file {
20 	struct file *filp;
21 	/* serializes accesses to migration data */
22 	struct mutex lock;
23 	struct xe_vfio_pci_core_device *xe_vdev;
24 	u8 disabled:1;
25 };
26 
27 struct xe_vfio_pci_core_device {
28 	struct vfio_pci_core_device core_device;
29 	struct xe_device *xe;
30 	/* PF internal control uses vfid index starting from 1 */
31 	unsigned int vfid;
32 	u8 deferred_reset:1;
33 	/* protects migration state */
34 	struct mutex state_mutex;
35 	enum vfio_device_mig_state mig_state;
36 	/* protects the reset_done flow */
37 	spinlock_t reset_lock;
38 	struct xe_vfio_pci_migration_file *migf;
39 };
40 
41 #define xe_vdev_to_dev(xe_vdev) (&(xe_vdev)->core_device.pdev->dev)
42 
43 static void xe_vfio_pci_disable_file(struct xe_vfio_pci_migration_file *migf)
44 {
45 	mutex_lock(&migf->lock);
46 	migf->disabled = true;
47 	mutex_unlock(&migf->lock);
48 }
49 
50 static void xe_vfio_pci_put_file(struct xe_vfio_pci_core_device *xe_vdev)
51 {
52 	xe_vfio_pci_disable_file(xe_vdev->migf);
53 	fput(xe_vdev->migf->filp);
54 	xe_vdev->migf = NULL;
55 }
56 
57 static void xe_vfio_pci_reset(struct xe_vfio_pci_core_device *xe_vdev)
58 {
59 	if (xe_vdev->migf)
60 		xe_vfio_pci_put_file(xe_vdev);
61 
62 	xe_vdev->mig_state = VFIO_DEVICE_STATE_RUNNING;
63 }
64 
65 static void xe_vfio_pci_state_mutex_lock(struct xe_vfio_pci_core_device *xe_vdev)
66 {
67 	mutex_lock(&xe_vdev->state_mutex);
68 }
69 
70 /*
71  * This function is called in all state_mutex unlock cases to
72  * handle a 'deferred_reset' if exists.
73  */
74 static void xe_vfio_pci_state_mutex_unlock(struct xe_vfio_pci_core_device *xe_vdev)
75 {
76 again:
77 	spin_lock(&xe_vdev->reset_lock);
78 	if (xe_vdev->deferred_reset) {
79 		xe_vdev->deferred_reset = false;
80 		spin_unlock(&xe_vdev->reset_lock);
81 		xe_vfio_pci_reset(xe_vdev);
82 		goto again;
83 	}
84 	mutex_unlock(&xe_vdev->state_mutex);
85 	spin_unlock(&xe_vdev->reset_lock);
86 }
87 
88 static void xe_vfio_pci_reset_done(struct pci_dev *pdev)
89 {
90 	struct xe_vfio_pci_core_device *xe_vdev = pci_get_drvdata(pdev);
91 	int ret;
92 
93 	if (!pdev->is_virtfn)
94 		return;
95 
96 	/*
97 	 * VF FLR requires additional processing done by PF driver.
98 	 * The processing is done after FLR is already finished from PCIe
99 	 * perspective.
100 	 * In order to avoid a scenario where VF is used while PF processing
101 	 * is still in progress, additional synchronization point is needed.
102 	 */
103 	ret = xe_sriov_vfio_wait_flr_done(xe_vdev->xe, xe_vdev->vfid);
104 	if (ret)
105 		dev_err(&pdev->dev, "Failed to wait for FLR: %d\n", ret);
106 
107 	if (!xe_vdev->vfid)
108 		return;
109 
110 	/*
111 	 * As the higher VFIO layers are holding locks across reset and using
112 	 * those same locks with the mm_lock we need to prevent ABBA deadlock
113 	 * with the state_mutex and mm_lock.
114 	 * In case the state_mutex was taken already we defer the cleanup work
115 	 * to the unlock flow of the other running context.
116 	 */
117 	spin_lock(&xe_vdev->reset_lock);
118 	xe_vdev->deferred_reset = true;
119 	if (!mutex_trylock(&xe_vdev->state_mutex)) {
120 		spin_unlock(&xe_vdev->reset_lock);
121 		return;
122 	}
123 	spin_unlock(&xe_vdev->reset_lock);
124 	xe_vfio_pci_state_mutex_unlock(xe_vdev);
125 
126 	xe_vfio_pci_reset(xe_vdev);
127 }
128 
129 static const struct pci_error_handlers xe_vfio_pci_err_handlers = {
130 	.reset_done = xe_vfio_pci_reset_done,
131 	.error_detected = vfio_pci_core_aer_err_detected,
132 };
133 
134 static int xe_vfio_pci_open_device(struct vfio_device *core_vdev)
135 {
136 	struct xe_vfio_pci_core_device *xe_vdev =
137 		container_of(core_vdev, struct xe_vfio_pci_core_device, core_device.vdev);
138 	struct vfio_pci_core_device *vdev = &xe_vdev->core_device;
139 	int ret;
140 
141 	ret = vfio_pci_core_enable(vdev);
142 	if (ret)
143 		return ret;
144 
145 	xe_vdev->mig_state = VFIO_DEVICE_STATE_RUNNING;
146 
147 	vfio_pci_core_finish_enable(vdev);
148 
149 	return 0;
150 }
151 
152 static void xe_vfio_pci_close_device(struct vfio_device *core_vdev)
153 {
154 	struct xe_vfio_pci_core_device *xe_vdev =
155 		container_of(core_vdev, struct xe_vfio_pci_core_device, core_device.vdev);
156 
157 	xe_vfio_pci_state_mutex_lock(xe_vdev);
158 	xe_vfio_pci_reset(xe_vdev);
159 	xe_vfio_pci_state_mutex_unlock(xe_vdev);
160 	vfio_pci_core_close_device(core_vdev);
161 }
162 
163 static int xe_vfio_pci_release_file(struct inode *inode, struct file *filp)
164 {
165 	struct xe_vfio_pci_migration_file *migf = filp->private_data;
166 
167 	mutex_destroy(&migf->lock);
168 	kfree(migf);
169 
170 	return 0;
171 }
172 
173 static ssize_t xe_vfio_pci_save_read(struct file *filp, char __user *buf, size_t len, loff_t *pos)
174 {
175 	struct xe_vfio_pci_migration_file *migf = filp->private_data;
176 	ssize_t ret;
177 
178 	if (pos)
179 		return -ESPIPE;
180 
181 	mutex_lock(&migf->lock);
182 	if (migf->disabled) {
183 		mutex_unlock(&migf->lock);
184 		return -ENODEV;
185 	}
186 
187 	ret = xe_sriov_vfio_data_read(migf->xe_vdev->xe, migf->xe_vdev->vfid, buf, len);
188 	mutex_unlock(&migf->lock);
189 
190 	return ret;
191 }
192 
193 static const struct file_operations xe_vfio_pci_save_fops = {
194 	.owner = THIS_MODULE,
195 	.read = xe_vfio_pci_save_read,
196 	.release = xe_vfio_pci_release_file,
197 	.llseek = noop_llseek,
198 };
199 
200 static ssize_t xe_vfio_pci_resume_write(struct file *filp, const char __user *buf,
201 					size_t len, loff_t *pos)
202 {
203 	struct xe_vfio_pci_migration_file *migf = filp->private_data;
204 	ssize_t ret;
205 
206 	if (pos)
207 		return -ESPIPE;
208 
209 	mutex_lock(&migf->lock);
210 	if (migf->disabled) {
211 		mutex_unlock(&migf->lock);
212 		return -ENODEV;
213 	}
214 
215 	ret = xe_sriov_vfio_data_write(migf->xe_vdev->xe, migf->xe_vdev->vfid, buf, len);
216 	mutex_unlock(&migf->lock);
217 
218 	return ret;
219 }
220 
221 static const struct file_operations xe_vfio_pci_resume_fops = {
222 	.owner = THIS_MODULE,
223 	.write = xe_vfio_pci_resume_write,
224 	.release = xe_vfio_pci_release_file,
225 	.llseek = noop_llseek,
226 };
227 
228 static const char *vfio_dev_state_str(u32 state)
229 {
230 	switch (state) {
231 	case VFIO_DEVICE_STATE_RUNNING: return "running";
232 	case VFIO_DEVICE_STATE_RUNNING_P2P: return "running_p2p";
233 	case VFIO_DEVICE_STATE_STOP_COPY: return "stopcopy";
234 	case VFIO_DEVICE_STATE_STOP: return "stop";
235 	case VFIO_DEVICE_STATE_RESUMING: return "resuming";
236 	case VFIO_DEVICE_STATE_ERROR: return "error";
237 	default: return "";
238 	}
239 }
240 
241 enum xe_vfio_pci_file_type {
242 	XE_VFIO_FILE_SAVE = 0,
243 	XE_VFIO_FILE_RESUME,
244 };
245 
246 static struct xe_vfio_pci_migration_file *
247 xe_vfio_pci_alloc_file(struct xe_vfio_pci_core_device *xe_vdev,
248 		       enum xe_vfio_pci_file_type type)
249 {
250 	struct xe_vfio_pci_migration_file *migf;
251 	const struct file_operations *fops;
252 	int flags;
253 	int ret;
254 
255 	migf = kzalloc(sizeof(*migf), GFP_KERNEL_ACCOUNT);
256 	if (!migf)
257 		return ERR_PTR(-ENOMEM);
258 
259 	fops = type == XE_VFIO_FILE_SAVE ? &xe_vfio_pci_save_fops : &xe_vfio_pci_resume_fops;
260 	flags = type == XE_VFIO_FILE_SAVE ? O_RDONLY : O_WRONLY;
261 	migf->filp = anon_inode_getfile("xe_vfio_mig", fops, migf, flags);
262 	if (IS_ERR(migf->filp)) {
263 		ret = PTR_ERR(migf->filp);
264 		kfree(migf);
265 		return ERR_PTR(ret);
266 	}
267 
268 	mutex_init(&migf->lock);
269 	migf->xe_vdev = xe_vdev;
270 	xe_vdev->migf = migf;
271 
272 	stream_open(migf->filp->f_inode, migf->filp);
273 
274 	return migf;
275 }
276 
277 static struct file *
278 xe_vfio_set_state(struct xe_vfio_pci_core_device *xe_vdev, u32 new)
279 {
280 	u32 cur = xe_vdev->mig_state;
281 	int ret;
282 
283 	dev_dbg(xe_vdev_to_dev(xe_vdev),
284 		"state: %s->%s\n", vfio_dev_state_str(cur), vfio_dev_state_str(new));
285 
286 	/*
287 	 * "STOP" handling is reused for "RUNNING_P2P", as the device doesn't
288 	 * have the capability to selectively block outgoing p2p DMA transfers.
289 	 * While the device is allowing BAR accesses when the VF is stopped, it
290 	 * is not processing any new workload requests, effectively stopping
291 	 * any outgoing DMA transfers (not just p2p).
292 	 * Any VRAM / MMIO accesses occurring during "RUNNING_P2P" are kept and
293 	 * will be migrated to target VF during stop-copy.
294 	 */
295 	if (cur == VFIO_DEVICE_STATE_RUNNING && new == VFIO_DEVICE_STATE_RUNNING_P2P) {
296 		ret = xe_sriov_vfio_suspend_device(xe_vdev->xe, xe_vdev->vfid);
297 		if (ret)
298 			goto err;
299 
300 		return NULL;
301 	}
302 
303 	if ((cur == VFIO_DEVICE_STATE_RUNNING_P2P && new == VFIO_DEVICE_STATE_STOP) ||
304 	    (cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_RUNNING_P2P))
305 		return NULL;
306 
307 	if (cur == VFIO_DEVICE_STATE_RUNNING_P2P && new == VFIO_DEVICE_STATE_RUNNING) {
308 		ret = xe_sriov_vfio_resume_device(xe_vdev->xe, xe_vdev->vfid);
309 		if (ret)
310 			goto err;
311 
312 		return NULL;
313 	}
314 
315 	if (cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_STOP_COPY) {
316 		struct xe_vfio_pci_migration_file *migf;
317 
318 		migf = xe_vfio_pci_alloc_file(xe_vdev, XE_VFIO_FILE_SAVE);
319 		if (IS_ERR(migf)) {
320 			ret = PTR_ERR(migf);
321 			goto err;
322 		}
323 		get_file(migf->filp);
324 
325 		ret = xe_sriov_vfio_stop_copy_enter(xe_vdev->xe, xe_vdev->vfid);
326 		if (ret) {
327 			fput(migf->filp);
328 			goto err;
329 		}
330 
331 		return migf->filp;
332 	}
333 
334 	if (cur == VFIO_DEVICE_STATE_STOP_COPY && new == VFIO_DEVICE_STATE_STOP) {
335 		if (xe_vdev->migf)
336 			xe_vfio_pci_put_file(xe_vdev);
337 
338 		ret = xe_sriov_vfio_stop_copy_exit(xe_vdev->xe, xe_vdev->vfid);
339 		if (ret)
340 			goto err;
341 
342 		return NULL;
343 	}
344 
345 	if (cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_RESUMING) {
346 		struct xe_vfio_pci_migration_file *migf;
347 
348 		migf = xe_vfio_pci_alloc_file(xe_vdev, XE_VFIO_FILE_RESUME);
349 		if (IS_ERR(migf)) {
350 			ret = PTR_ERR(migf);
351 			goto err;
352 		}
353 		get_file(migf->filp);
354 
355 		ret = xe_sriov_vfio_resume_data_enter(xe_vdev->xe, xe_vdev->vfid);
356 		if (ret) {
357 			fput(migf->filp);
358 			goto err;
359 		}
360 
361 		return migf->filp;
362 	}
363 
364 	if (cur == VFIO_DEVICE_STATE_RESUMING && new == VFIO_DEVICE_STATE_STOP) {
365 		if (xe_vdev->migf)
366 			xe_vfio_pci_put_file(xe_vdev);
367 
368 		ret = xe_sriov_vfio_resume_data_exit(xe_vdev->xe, xe_vdev->vfid);
369 		if (ret)
370 			goto err;
371 
372 		return NULL;
373 	}
374 
375 	WARN(true, "Unknown state transition %d->%d", cur, new);
376 	return ERR_PTR(-EINVAL);
377 
378 err:
379 	dev_dbg(xe_vdev_to_dev(xe_vdev),
380 		"Failed to transition state: %s->%s err=%d\n",
381 		vfio_dev_state_str(cur), vfio_dev_state_str(new), ret);
382 	return ERR_PTR(ret);
383 }
384 
385 static struct file *
386 xe_vfio_pci_set_device_state(struct vfio_device *core_vdev,
387 			     enum vfio_device_mig_state new_state)
388 {
389 	struct xe_vfio_pci_core_device *xe_vdev =
390 		container_of(core_vdev, struct xe_vfio_pci_core_device, core_device.vdev);
391 	enum vfio_device_mig_state next_state;
392 	struct file *f = NULL;
393 	int ret;
394 
395 	xe_vfio_pci_state_mutex_lock(xe_vdev);
396 	while (new_state != xe_vdev->mig_state) {
397 		ret = vfio_mig_get_next_state(core_vdev, xe_vdev->mig_state,
398 					      new_state, &next_state);
399 		if (ret) {
400 			xe_sriov_vfio_error(xe_vdev->xe, xe_vdev->vfid);
401 			f = ERR_PTR(ret);
402 			break;
403 		}
404 		f = xe_vfio_set_state(xe_vdev, next_state);
405 		if (IS_ERR(f))
406 			break;
407 
408 		xe_vdev->mig_state = next_state;
409 
410 		/* Multiple state transitions with non-NULL file in the middle */
411 		if (f && new_state != xe_vdev->mig_state) {
412 			fput(f);
413 			f = ERR_PTR(-EINVAL);
414 			break;
415 		}
416 	}
417 	xe_vfio_pci_state_mutex_unlock(xe_vdev);
418 
419 	return f;
420 }
421 
422 static int xe_vfio_pci_get_device_state(struct vfio_device *core_vdev,
423 					enum vfio_device_mig_state *curr_state)
424 {
425 	struct xe_vfio_pci_core_device *xe_vdev =
426 		container_of(core_vdev, struct xe_vfio_pci_core_device, core_device.vdev);
427 
428 	xe_vfio_pci_state_mutex_lock(xe_vdev);
429 	*curr_state = xe_vdev->mig_state;
430 	xe_vfio_pci_state_mutex_unlock(xe_vdev);
431 
432 	return 0;
433 }
434 
435 static int xe_vfio_pci_get_data_size(struct vfio_device *vdev,
436 				     unsigned long *stop_copy_length)
437 {
438 	struct xe_vfio_pci_core_device *xe_vdev =
439 		container_of(vdev, struct xe_vfio_pci_core_device, core_device.vdev);
440 
441 	xe_vfio_pci_state_mutex_lock(xe_vdev);
442 	*stop_copy_length = xe_sriov_vfio_stop_copy_size(xe_vdev->xe, xe_vdev->vfid);
443 	xe_vfio_pci_state_mutex_unlock(xe_vdev);
444 
445 	return 0;
446 }
447 
448 static const struct vfio_migration_ops xe_vfio_pci_migration_ops = {
449 	.migration_set_state = xe_vfio_pci_set_device_state,
450 	.migration_get_state = xe_vfio_pci_get_device_state,
451 	.migration_get_data_size = xe_vfio_pci_get_data_size,
452 };
453 
454 static void xe_vfio_pci_migration_init(struct xe_vfio_pci_core_device *xe_vdev)
455 {
456 	struct vfio_device *core_vdev = &xe_vdev->core_device.vdev;
457 	struct pci_dev *pdev = to_pci_dev(core_vdev->dev);
458 	struct xe_device *xe = xe_sriov_vfio_get_pf(pdev);
459 
460 	if (!xe)
461 		return;
462 	if (!xe_sriov_vfio_migration_supported(xe))
463 		return;
464 
465 	mutex_init(&xe_vdev->state_mutex);
466 	spin_lock_init(&xe_vdev->reset_lock);
467 
468 	/* PF internal control uses vfid index starting from 1 */
469 	xe_vdev->vfid = pci_iov_vf_id(pdev) + 1;
470 	xe_vdev->xe = xe;
471 
472 	core_vdev->migration_flags = VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_P2P;
473 	core_vdev->mig_ops = &xe_vfio_pci_migration_ops;
474 }
475 
476 static void xe_vfio_pci_migration_fini(struct xe_vfio_pci_core_device *xe_vdev)
477 {
478 	if (!xe_vdev->vfid)
479 		return;
480 
481 	mutex_destroy(&xe_vdev->state_mutex);
482 }
483 
484 static int xe_vfio_pci_init_dev(struct vfio_device *core_vdev)
485 {
486 	struct xe_vfio_pci_core_device *xe_vdev =
487 		container_of(core_vdev, struct xe_vfio_pci_core_device, core_device.vdev);
488 
489 	xe_vfio_pci_migration_init(xe_vdev);
490 
491 	return vfio_pci_core_init_dev(core_vdev);
492 }
493 
494 static void xe_vfio_pci_release_dev(struct vfio_device *core_vdev)
495 {
496 	struct xe_vfio_pci_core_device *xe_vdev =
497 		container_of(core_vdev, struct xe_vfio_pci_core_device, core_device.vdev);
498 
499 	xe_vfio_pci_migration_fini(xe_vdev);
500 }
501 
502 static const struct vfio_device_ops xe_vfio_pci_ops = {
503 	.name = "xe-vfio-pci",
504 	.init = xe_vfio_pci_init_dev,
505 	.release = xe_vfio_pci_release_dev,
506 	.open_device = xe_vfio_pci_open_device,
507 	.close_device = xe_vfio_pci_close_device,
508 	.ioctl = vfio_pci_core_ioctl,
509 	.get_region_info_caps = vfio_pci_ioctl_get_region_info,
510 	.device_feature = vfio_pci_core_ioctl_feature,
511 	.read = vfio_pci_core_read,
512 	.write = vfio_pci_core_write,
513 	.mmap = vfio_pci_core_mmap,
514 	.request = vfio_pci_core_request,
515 	.match = vfio_pci_core_match,
516 	.match_token_uuid = vfio_pci_core_match_token_uuid,
517 	.bind_iommufd = vfio_iommufd_physical_bind,
518 	.unbind_iommufd = vfio_iommufd_physical_unbind,
519 	.attach_ioas = vfio_iommufd_physical_attach_ioas,
520 	.detach_ioas = vfio_iommufd_physical_detach_ioas,
521 };
522 
523 static int xe_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
524 {
525 	struct xe_vfio_pci_core_device *xe_vdev;
526 	int ret;
527 
528 	xe_vdev = vfio_alloc_device(xe_vfio_pci_core_device, core_device.vdev, &pdev->dev,
529 				    &xe_vfio_pci_ops);
530 	if (IS_ERR(xe_vdev))
531 		return PTR_ERR(xe_vdev);
532 
533 	dev_set_drvdata(&pdev->dev, &xe_vdev->core_device);
534 
535 	ret = vfio_pci_core_register_device(&xe_vdev->core_device);
536 	if (ret) {
537 		vfio_put_device(&xe_vdev->core_device.vdev);
538 		return ret;
539 	}
540 
541 	return 0;
542 }
543 
544 static void xe_vfio_pci_remove(struct pci_dev *pdev)
545 {
546 	struct xe_vfio_pci_core_device *xe_vdev = pci_get_drvdata(pdev);
547 
548 	vfio_pci_core_unregister_device(&xe_vdev->core_device);
549 	vfio_put_device(&xe_vdev->core_device.vdev);
550 }
551 
552 #define INTEL_PCI_VFIO_DEVICE(_id) { \
553 	PCI_DRIVER_OVERRIDE_DEVICE_VFIO(PCI_VENDOR_ID_INTEL, (_id)) \
554 }
555 
556 static const struct pci_device_id xe_vfio_pci_table[] = {
557 	INTEL_PTL_IDS(INTEL_PCI_VFIO_DEVICE),
558 	INTEL_WCL_IDS(INTEL_PCI_VFIO_DEVICE),
559 	INTEL_BMG_IDS(INTEL_PCI_VFIO_DEVICE),
560 	{}
561 };
562 MODULE_DEVICE_TABLE(pci, xe_vfio_pci_table);
563 
564 static struct pci_driver xe_vfio_pci_driver = {
565 	.name = "xe-vfio-pci",
566 	.id_table = xe_vfio_pci_table,
567 	.probe = xe_vfio_pci_probe,
568 	.remove = xe_vfio_pci_remove,
569 	.err_handler = &xe_vfio_pci_err_handlers,
570 	.driver_managed_dma = true,
571 };
572 module_pci_driver(xe_vfio_pci_driver);
573 
574 MODULE_LICENSE("GPL");
575 MODULE_AUTHOR("Michał Winiarski <michal.winiarski@intel.com>");
576 MODULE_DESCRIPTION("VFIO PCI driver with migration support for Intel Graphics");
577