xref: /linux/drivers/pci/iov.c (revision 424f0750edd5af866f80f5e65998e0610503cb5c)
1 /*
2  * drivers/pci/iov.c
3  *
4  * Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
5  *
6  * PCI Express I/O Virtualization (IOV) support.
7  *   Single Root IOV 1.0
8  *   Address Translation Service 1.0
9  */
10 
11 #include <linux/pci.h>
12 #include <linux/slab.h>
13 #include <linux/mutex.h>
14 #include <linux/export.h>
15 #include <linux/string.h>
16 #include <linux/delay.h>
17 #include <linux/pci-ats.h>
18 #include "pci.h"
19 
20 #define VIRTFN_ID_LEN	16
21 
22 static inline u8 virtfn_bus(struct pci_dev *dev, int id)
23 {
24 	return dev->bus->number + ((dev->devfn + dev->sriov->offset +
25 				    dev->sriov->stride * id) >> 8);
26 }
27 
28 static inline u8 virtfn_devfn(struct pci_dev *dev, int id)
29 {
30 	return (dev->devfn + dev->sriov->offset +
31 		dev->sriov->stride * id) & 0xff;
32 }
33 
34 static struct pci_bus *virtfn_add_bus(struct pci_bus *bus, int busnr)
35 {
36 	int rc;
37 	struct pci_bus *child;
38 
39 	if (bus->number == busnr)
40 		return bus;
41 
42 	child = pci_find_bus(pci_domain_nr(bus), busnr);
43 	if (child)
44 		return child;
45 
46 	child = pci_add_new_bus(bus, NULL, busnr);
47 	if (!child)
48 		return NULL;
49 
50 	child->subordinate = busnr;
51 	child->dev.parent = bus->bridge;
52 	rc = pci_bus_add_child(child);
53 	if (rc) {
54 		pci_remove_bus(child);
55 		return NULL;
56 	}
57 
58 	return child;
59 }
60 
61 static void virtfn_remove_bus(struct pci_bus *bus, int busnr)
62 {
63 	struct pci_bus *child;
64 
65 	if (bus->number == busnr)
66 		return;
67 
68 	child = pci_find_bus(pci_domain_nr(bus), busnr);
69 	BUG_ON(!child);
70 
71 	if (list_empty(&child->devices))
72 		pci_remove_bus(child);
73 }
74 
75 static int virtfn_add(struct pci_dev *dev, int id, int reset)
76 {
77 	int i;
78 	int rc;
79 	u64 size;
80 	char buf[VIRTFN_ID_LEN];
81 	struct pci_dev *virtfn;
82 	struct resource *res;
83 	struct pci_sriov *iov = dev->sriov;
84 
85 	virtfn = alloc_pci_dev();
86 	if (!virtfn)
87 		return -ENOMEM;
88 
89 	mutex_lock(&iov->dev->sriov->lock);
90 	virtfn->bus = virtfn_add_bus(dev->bus, virtfn_bus(dev, id));
91 	if (!virtfn->bus) {
92 		kfree(virtfn);
93 		mutex_unlock(&iov->dev->sriov->lock);
94 		return -ENOMEM;
95 	}
96 	virtfn->devfn = virtfn_devfn(dev, id);
97 	virtfn->vendor = dev->vendor;
98 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_DID, &virtfn->device);
99 	pci_setup_device(virtfn);
100 	virtfn->dev.parent = dev->dev.parent;
101 
102 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
103 		res = dev->resource + PCI_IOV_RESOURCES + i;
104 		if (!res->parent)
105 			continue;
106 		virtfn->resource[i].name = pci_name(virtfn);
107 		virtfn->resource[i].flags = res->flags;
108 		size = resource_size(res);
109 		do_div(size, iov->total);
110 		virtfn->resource[i].start = res->start + size * id;
111 		virtfn->resource[i].end = virtfn->resource[i].start + size - 1;
112 		rc = request_resource(res, &virtfn->resource[i]);
113 		BUG_ON(rc);
114 	}
115 
116 	if (reset)
117 		__pci_reset_function(virtfn);
118 
119 	pci_device_add(virtfn, virtfn->bus);
120 	mutex_unlock(&iov->dev->sriov->lock);
121 
122 	virtfn->physfn = pci_dev_get(dev);
123 	virtfn->is_virtfn = 1;
124 
125 	rc = pci_bus_add_device(virtfn);
126 	if (rc)
127 		goto failed1;
128 	sprintf(buf, "virtfn%u", id);
129 	rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
130 	if (rc)
131 		goto failed1;
132 	rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
133 	if (rc)
134 		goto failed2;
135 
136 	kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
137 
138 	return 0;
139 
140 failed2:
141 	sysfs_remove_link(&dev->dev.kobj, buf);
142 failed1:
143 	pci_dev_put(dev);
144 	mutex_lock(&iov->dev->sriov->lock);
145 	pci_remove_bus_device(virtfn);
146 	virtfn_remove_bus(dev->bus, virtfn_bus(dev, id));
147 	mutex_unlock(&iov->dev->sriov->lock);
148 
149 	return rc;
150 }
151 
152 static void virtfn_remove(struct pci_dev *dev, int id, int reset)
153 {
154 	char buf[VIRTFN_ID_LEN];
155 	struct pci_bus *bus;
156 	struct pci_dev *virtfn;
157 	struct pci_sriov *iov = dev->sriov;
158 
159 	bus = pci_find_bus(pci_domain_nr(dev->bus), virtfn_bus(dev, id));
160 	if (!bus)
161 		return;
162 
163 	virtfn = pci_get_slot(bus, virtfn_devfn(dev, id));
164 	if (!virtfn)
165 		return;
166 
167 	pci_dev_put(virtfn);
168 
169 	if (reset) {
170 		device_release_driver(&virtfn->dev);
171 		__pci_reset_function(virtfn);
172 	}
173 
174 	sprintf(buf, "virtfn%u", id);
175 	sysfs_remove_link(&dev->dev.kobj, buf);
176 	sysfs_remove_link(&virtfn->dev.kobj, "physfn");
177 
178 	mutex_lock(&iov->dev->sriov->lock);
179 	pci_remove_bus_device(virtfn);
180 	virtfn_remove_bus(dev->bus, virtfn_bus(dev, id));
181 	mutex_unlock(&iov->dev->sriov->lock);
182 
183 	pci_dev_put(dev);
184 }
185 
186 static int sriov_migration(struct pci_dev *dev)
187 {
188 	u16 status;
189 	struct pci_sriov *iov = dev->sriov;
190 
191 	if (!iov->nr_virtfn)
192 		return 0;
193 
194 	if (!(iov->cap & PCI_SRIOV_CAP_VFM))
195 		return 0;
196 
197 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_STATUS, &status);
198 	if (!(status & PCI_SRIOV_STATUS_VFM))
199 		return 0;
200 
201 	schedule_work(&iov->mtask);
202 
203 	return 1;
204 }
205 
206 static void sriov_migration_task(struct work_struct *work)
207 {
208 	int i;
209 	u8 state;
210 	u16 status;
211 	struct pci_sriov *iov = container_of(work, struct pci_sriov, mtask);
212 
213 	for (i = iov->initial; i < iov->nr_virtfn; i++) {
214 		state = readb(iov->mstate + i);
215 		if (state == PCI_SRIOV_VFM_MI) {
216 			writeb(PCI_SRIOV_VFM_AV, iov->mstate + i);
217 			state = readb(iov->mstate + i);
218 			if (state == PCI_SRIOV_VFM_AV)
219 				virtfn_add(iov->self, i, 1);
220 		} else if (state == PCI_SRIOV_VFM_MO) {
221 			virtfn_remove(iov->self, i, 1);
222 			writeb(PCI_SRIOV_VFM_UA, iov->mstate + i);
223 			state = readb(iov->mstate + i);
224 			if (state == PCI_SRIOV_VFM_AV)
225 				virtfn_add(iov->self, i, 0);
226 		}
227 	}
228 
229 	pci_read_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, &status);
230 	status &= ~PCI_SRIOV_STATUS_VFM;
231 	pci_write_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, status);
232 }
233 
234 static int sriov_enable_migration(struct pci_dev *dev, int nr_virtfn)
235 {
236 	int bir;
237 	u32 table;
238 	resource_size_t pa;
239 	struct pci_sriov *iov = dev->sriov;
240 
241 	if (nr_virtfn <= iov->initial)
242 		return 0;
243 
244 	pci_read_config_dword(dev, iov->pos + PCI_SRIOV_VFM, &table);
245 	bir = PCI_SRIOV_VFM_BIR(table);
246 	if (bir > PCI_STD_RESOURCE_END)
247 		return -EIO;
248 
249 	table = PCI_SRIOV_VFM_OFFSET(table);
250 	if (table + nr_virtfn > pci_resource_len(dev, bir))
251 		return -EIO;
252 
253 	pa = pci_resource_start(dev, bir) + table;
254 	iov->mstate = ioremap(pa, nr_virtfn);
255 	if (!iov->mstate)
256 		return -ENOMEM;
257 
258 	INIT_WORK(&iov->mtask, sriov_migration_task);
259 
260 	iov->ctrl |= PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR;
261 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
262 
263 	return 0;
264 }
265 
266 static void sriov_disable_migration(struct pci_dev *dev)
267 {
268 	struct pci_sriov *iov = dev->sriov;
269 
270 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR);
271 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
272 
273 	cancel_work_sync(&iov->mtask);
274 	iounmap(iov->mstate);
275 }
276 
277 static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
278 {
279 	int rc;
280 	int i, j;
281 	int nres;
282 	u16 offset, stride, initial;
283 	struct resource *res;
284 	struct pci_dev *pdev;
285 	struct pci_sriov *iov = dev->sriov;
286 
287 	if (!nr_virtfn)
288 		return 0;
289 
290 	if (iov->nr_virtfn)
291 		return -EINVAL;
292 
293 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_INITIAL_VF, &initial);
294 	if (initial > iov->total ||
295 	    (!(iov->cap & PCI_SRIOV_CAP_VFM) && (initial != iov->total)))
296 		return -EIO;
297 
298 	if (nr_virtfn < 0 || nr_virtfn > iov->total ||
299 	    (!(iov->cap & PCI_SRIOV_CAP_VFM) && (nr_virtfn > initial)))
300 		return -EINVAL;
301 
302 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn);
303 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_OFFSET, &offset);
304 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_STRIDE, &stride);
305 	if (!offset || (nr_virtfn > 1 && !stride))
306 		return -EIO;
307 
308 	nres = 0;
309 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
310 		res = dev->resource + PCI_IOV_RESOURCES + i;
311 		if (res->parent)
312 			nres++;
313 	}
314 	if (nres != iov->nres) {
315 		dev_err(&dev->dev, "not enough MMIO resources for SR-IOV\n");
316 		return -ENOMEM;
317 	}
318 
319 	iov->offset = offset;
320 	iov->stride = stride;
321 
322 	if (virtfn_bus(dev, nr_virtfn - 1) > dev->bus->subordinate) {
323 		dev_err(&dev->dev, "SR-IOV: bus number out of range\n");
324 		return -ENOMEM;
325 	}
326 
327 	if (iov->link != dev->devfn) {
328 		pdev = pci_get_slot(dev->bus, iov->link);
329 		if (!pdev)
330 			return -ENODEV;
331 
332 		pci_dev_put(pdev);
333 
334 		if (!pdev->is_physfn)
335 			return -ENODEV;
336 
337 		rc = sysfs_create_link(&dev->dev.kobj,
338 					&pdev->dev.kobj, "dep_link");
339 		if (rc)
340 			return rc;
341 	}
342 
343 	iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
344 	pci_block_user_cfg_access(dev);
345 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
346 	msleep(100);
347 	pci_unblock_user_cfg_access(dev);
348 
349 	iov->initial = initial;
350 	if (nr_virtfn < initial)
351 		initial = nr_virtfn;
352 
353 	for (i = 0; i < initial; i++) {
354 		rc = virtfn_add(dev, i, 0);
355 		if (rc)
356 			goto failed;
357 	}
358 
359 	if (iov->cap & PCI_SRIOV_CAP_VFM) {
360 		rc = sriov_enable_migration(dev, nr_virtfn);
361 		if (rc)
362 			goto failed;
363 	}
364 
365 	kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
366 	iov->nr_virtfn = nr_virtfn;
367 
368 	return 0;
369 
370 failed:
371 	for (j = 0; j < i; j++)
372 		virtfn_remove(dev, j, 0);
373 
374 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
375 	pci_block_user_cfg_access(dev);
376 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
377 	ssleep(1);
378 	pci_unblock_user_cfg_access(dev);
379 
380 	if (iov->link != dev->devfn)
381 		sysfs_remove_link(&dev->dev.kobj, "dep_link");
382 
383 	return rc;
384 }
385 
386 static void sriov_disable(struct pci_dev *dev)
387 {
388 	int i;
389 	struct pci_sriov *iov = dev->sriov;
390 
391 	if (!iov->nr_virtfn)
392 		return;
393 
394 	if (iov->cap & PCI_SRIOV_CAP_VFM)
395 		sriov_disable_migration(dev);
396 
397 	for (i = 0; i < iov->nr_virtfn; i++)
398 		virtfn_remove(dev, i, 0);
399 
400 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
401 	pci_block_user_cfg_access(dev);
402 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
403 	ssleep(1);
404 	pci_unblock_user_cfg_access(dev);
405 
406 	if (iov->link != dev->devfn)
407 		sysfs_remove_link(&dev->dev.kobj, "dep_link");
408 
409 	iov->nr_virtfn = 0;
410 }
411 
412 static int sriov_init(struct pci_dev *dev, int pos)
413 {
414 	int i;
415 	int rc;
416 	int nres;
417 	u32 pgsz;
418 	u16 ctrl, total, offset, stride;
419 	struct pci_sriov *iov;
420 	struct resource *res;
421 	struct pci_dev *pdev;
422 
423 	if (dev->pcie_type != PCI_EXP_TYPE_RC_END &&
424 	    dev->pcie_type != PCI_EXP_TYPE_ENDPOINT)
425 		return -ENODEV;
426 
427 	pci_read_config_word(dev, pos + PCI_SRIOV_CTRL, &ctrl);
428 	if (ctrl & PCI_SRIOV_CTRL_VFE) {
429 		pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, 0);
430 		ssleep(1);
431 	}
432 
433 	pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total);
434 	if (!total)
435 		return 0;
436 
437 	ctrl = 0;
438 	list_for_each_entry(pdev, &dev->bus->devices, bus_list)
439 		if (pdev->is_physfn)
440 			goto found;
441 
442 	pdev = NULL;
443 	if (pci_ari_enabled(dev->bus))
444 		ctrl |= PCI_SRIOV_CTRL_ARI;
445 
446 found:
447 	pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
448 	pci_write_config_word(dev, pos + PCI_SRIOV_NUM_VF, total);
449 	pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset);
450 	pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride);
451 	if (!offset || (total > 1 && !stride))
452 		return -EIO;
453 
454 	pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
455 	i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
456 	pgsz &= ~((1 << i) - 1);
457 	if (!pgsz)
458 		return -EIO;
459 
460 	pgsz &= ~(pgsz - 1);
461 	pci_write_config_dword(dev, pos + PCI_SRIOV_SYS_PGSIZE, pgsz);
462 
463 	nres = 0;
464 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
465 		res = dev->resource + PCI_IOV_RESOURCES + i;
466 		i += __pci_read_base(dev, pci_bar_unknown, res,
467 				     pos + PCI_SRIOV_BAR + i * 4);
468 		if (!res->flags)
469 			continue;
470 		if (resource_size(res) & (PAGE_SIZE - 1)) {
471 			rc = -EIO;
472 			goto failed;
473 		}
474 		res->end = res->start + resource_size(res) * total - 1;
475 		nres++;
476 	}
477 
478 	iov = kzalloc(sizeof(*iov), GFP_KERNEL);
479 	if (!iov) {
480 		rc = -ENOMEM;
481 		goto failed;
482 	}
483 
484 	iov->pos = pos;
485 	iov->nres = nres;
486 	iov->ctrl = ctrl;
487 	iov->total = total;
488 	iov->offset = offset;
489 	iov->stride = stride;
490 	iov->pgsz = pgsz;
491 	iov->self = dev;
492 	pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
493 	pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
494 	if (dev->pcie_type == PCI_EXP_TYPE_RC_END)
495 		iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);
496 
497 	if (pdev)
498 		iov->dev = pci_dev_get(pdev);
499 	else
500 		iov->dev = dev;
501 
502 	mutex_init(&iov->lock);
503 
504 	dev->sriov = iov;
505 	dev->is_physfn = 1;
506 
507 	return 0;
508 
509 failed:
510 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
511 		res = dev->resource + PCI_IOV_RESOURCES + i;
512 		res->flags = 0;
513 	}
514 
515 	return rc;
516 }
517 
518 static void sriov_release(struct pci_dev *dev)
519 {
520 	BUG_ON(dev->sriov->nr_virtfn);
521 
522 	if (dev != dev->sriov->dev)
523 		pci_dev_put(dev->sriov->dev);
524 
525 	mutex_destroy(&dev->sriov->lock);
526 
527 	kfree(dev->sriov);
528 	dev->sriov = NULL;
529 }
530 
531 static void sriov_restore_state(struct pci_dev *dev)
532 {
533 	int i;
534 	u16 ctrl;
535 	struct pci_sriov *iov = dev->sriov;
536 
537 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &ctrl);
538 	if (ctrl & PCI_SRIOV_CTRL_VFE)
539 		return;
540 
541 	for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++)
542 		pci_update_resource(dev, i);
543 
544 	pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
545 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, iov->nr_virtfn);
546 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
547 	if (iov->ctrl & PCI_SRIOV_CTRL_VFE)
548 		msleep(100);
549 }
550 
551 /**
552  * pci_iov_init - initialize the IOV capability
553  * @dev: the PCI device
554  *
555  * Returns 0 on success, or negative on failure.
556  */
557 int pci_iov_init(struct pci_dev *dev)
558 {
559 	int pos;
560 
561 	if (!pci_is_pcie(dev))
562 		return -ENODEV;
563 
564 	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
565 	if (pos)
566 		return sriov_init(dev, pos);
567 
568 	return -ENODEV;
569 }
570 
571 /**
572  * pci_iov_release - release resources used by the IOV capability
573  * @dev: the PCI device
574  */
575 void pci_iov_release(struct pci_dev *dev)
576 {
577 	if (dev->is_physfn)
578 		sriov_release(dev);
579 }
580 
581 /**
582  * pci_iov_resource_bar - get position of the SR-IOV BAR
583  * @dev: the PCI device
584  * @resno: the resource number
585  * @type: the BAR type to be filled in
586  *
587  * Returns position of the BAR encapsulated in the SR-IOV capability.
588  */
589 int pci_iov_resource_bar(struct pci_dev *dev, int resno,
590 			 enum pci_bar_type *type)
591 {
592 	if (resno < PCI_IOV_RESOURCES || resno > PCI_IOV_RESOURCE_END)
593 		return 0;
594 
595 	BUG_ON(!dev->is_physfn);
596 
597 	*type = pci_bar_unknown;
598 
599 	return dev->sriov->pos + PCI_SRIOV_BAR +
600 		4 * (resno - PCI_IOV_RESOURCES);
601 }
602 
603 /**
604  * pci_sriov_resource_alignment - get resource alignment for VF BAR
605  * @dev: the PCI device
606  * @resno: the resource number
607  *
608  * Returns the alignment of the VF BAR found in the SR-IOV capability.
609  * This is not the same as the resource size which is defined as
610  * the VF BAR size multiplied by the number of VFs.  The alignment
611  * is just the VF BAR size.
612  */
613 resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
614 {
615 	struct resource tmp;
616 	enum pci_bar_type type;
617 	int reg = pci_iov_resource_bar(dev, resno, &type);
618 
619 	if (!reg)
620 		return 0;
621 
622 	 __pci_read_base(dev, type, &tmp, reg);
623 	return resource_alignment(&tmp);
624 }
625 
626 /**
627  * pci_restore_iov_state - restore the state of the IOV capability
628  * @dev: the PCI device
629  */
630 void pci_restore_iov_state(struct pci_dev *dev)
631 {
632 	if (dev->is_physfn)
633 		sriov_restore_state(dev);
634 }
635 
636 /**
637  * pci_iov_bus_range - find bus range used by Virtual Function
638  * @bus: the PCI bus
639  *
640  * Returns max number of buses (exclude current one) used by Virtual
641  * Functions.
642  */
643 int pci_iov_bus_range(struct pci_bus *bus)
644 {
645 	int max = 0;
646 	u8 busnr;
647 	struct pci_dev *dev;
648 
649 	list_for_each_entry(dev, &bus->devices, bus_list) {
650 		if (!dev->is_physfn)
651 			continue;
652 		busnr = virtfn_bus(dev, dev->sriov->total - 1);
653 		if (busnr > max)
654 			max = busnr;
655 	}
656 
657 	return max ? max - bus->number : 0;
658 }
659 
660 /**
661  * pci_enable_sriov - enable the SR-IOV capability
662  * @dev: the PCI device
663  * @nr_virtfn: number of virtual functions to enable
664  *
665  * Returns 0 on success, or negative on failure.
666  */
667 int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
668 {
669 	might_sleep();
670 
671 	if (!dev->is_physfn)
672 		return -ENODEV;
673 
674 	return sriov_enable(dev, nr_virtfn);
675 }
676 EXPORT_SYMBOL_GPL(pci_enable_sriov);
677 
678 /**
679  * pci_disable_sriov - disable the SR-IOV capability
680  * @dev: the PCI device
681  */
682 void pci_disable_sriov(struct pci_dev *dev)
683 {
684 	might_sleep();
685 
686 	if (!dev->is_physfn)
687 		return;
688 
689 	sriov_disable(dev);
690 }
691 EXPORT_SYMBOL_GPL(pci_disable_sriov);
692 
693 /**
694  * pci_sriov_migration - notify SR-IOV core of Virtual Function Migration
695  * @dev: the PCI device
696  *
697  * Returns IRQ_HANDLED if the IRQ is handled, or IRQ_NONE if not.
698  *
699  * Physical Function driver is responsible to register IRQ handler using
700  * VF Migration Interrupt Message Number, and call this function when the
701  * interrupt is generated by the hardware.
702  */
703 irqreturn_t pci_sriov_migration(struct pci_dev *dev)
704 {
705 	if (!dev->is_physfn)
706 		return IRQ_NONE;
707 
708 	return sriov_migration(dev) ? IRQ_HANDLED : IRQ_NONE;
709 }
710 EXPORT_SYMBOL_GPL(pci_sriov_migration);
711 
712 /**
713  * pci_num_vf - return number of VFs associated with a PF device_release_driver
714  * @dev: the PCI device
715  *
716  * Returns number of VFs, or 0 if SR-IOV is not enabled.
717  */
718 int pci_num_vf(struct pci_dev *dev)
719 {
720 	if (!dev || !dev->is_physfn)
721 		return 0;
722 	else
723 		return dev->sriov->nr_virtfn;
724 }
725 EXPORT_SYMBOL_GPL(pci_num_vf);
726