xref: /openbmc/linux/drivers/pci/iov.c (revision 68198dca)
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 int pci_iov_virtfn_bus(struct pci_dev *dev, int vf_id)
23 {
24 	if (!dev->is_physfn)
25 		return -EINVAL;
26 	return dev->bus->number + ((dev->devfn + dev->sriov->offset +
27 				    dev->sriov->stride * vf_id) >> 8);
28 }
29 
30 int pci_iov_virtfn_devfn(struct pci_dev *dev, int vf_id)
31 {
32 	if (!dev->is_physfn)
33 		return -EINVAL;
34 	return (dev->devfn + dev->sriov->offset +
35 		dev->sriov->stride * vf_id) & 0xff;
36 }
37 
38 /*
39  * Per SR-IOV spec sec 3.3.10 and 3.3.11, First VF Offset and VF Stride may
40  * change when NumVFs changes.
41  *
42  * Update iov->offset and iov->stride when NumVFs is written.
43  */
44 static inline void pci_iov_set_numvfs(struct pci_dev *dev, int nr_virtfn)
45 {
46 	struct pci_sriov *iov = dev->sriov;
47 
48 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn);
49 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_OFFSET, &iov->offset);
50 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_STRIDE, &iov->stride);
51 }
52 
53 /*
54  * The PF consumes one bus number.  NumVFs, First VF Offset, and VF Stride
55  * determine how many additional bus numbers will be consumed by VFs.
56  *
57  * Iterate over all valid NumVFs, validate offset and stride, and calculate
58  * the maximum number of bus numbers that could ever be required.
59  */
60 static int compute_max_vf_buses(struct pci_dev *dev)
61 {
62 	struct pci_sriov *iov = dev->sriov;
63 	int nr_virtfn, busnr, rc = 0;
64 
65 	for (nr_virtfn = iov->total_VFs; nr_virtfn; nr_virtfn--) {
66 		pci_iov_set_numvfs(dev, nr_virtfn);
67 		if (!iov->offset || (nr_virtfn > 1 && !iov->stride)) {
68 			rc = -EIO;
69 			goto out;
70 		}
71 
72 		busnr = pci_iov_virtfn_bus(dev, nr_virtfn - 1);
73 		if (busnr > iov->max_VF_buses)
74 			iov->max_VF_buses = busnr;
75 	}
76 
77 out:
78 	pci_iov_set_numvfs(dev, 0);
79 	return rc;
80 }
81 
82 static struct pci_bus *virtfn_add_bus(struct pci_bus *bus, int busnr)
83 {
84 	struct pci_bus *child;
85 
86 	if (bus->number == busnr)
87 		return bus;
88 
89 	child = pci_find_bus(pci_domain_nr(bus), busnr);
90 	if (child)
91 		return child;
92 
93 	child = pci_add_new_bus(bus, NULL, busnr);
94 	if (!child)
95 		return NULL;
96 
97 	pci_bus_insert_busn_res(child, busnr, busnr);
98 
99 	return child;
100 }
101 
102 static void virtfn_remove_bus(struct pci_bus *physbus, struct pci_bus *virtbus)
103 {
104 	if (physbus != virtbus && list_empty(&virtbus->devices))
105 		pci_remove_bus(virtbus);
106 }
107 
108 resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno)
109 {
110 	if (!dev->is_physfn)
111 		return 0;
112 
113 	return dev->sriov->barsz[resno - PCI_IOV_RESOURCES];
114 }
115 
116 int pci_iov_add_virtfn(struct pci_dev *dev, int id)
117 {
118 	int i;
119 	int rc = -ENOMEM;
120 	u64 size;
121 	char buf[VIRTFN_ID_LEN];
122 	struct pci_dev *virtfn;
123 	struct resource *res;
124 	struct pci_sriov *iov = dev->sriov;
125 	struct pci_bus *bus;
126 
127 	bus = virtfn_add_bus(dev->bus, pci_iov_virtfn_bus(dev, id));
128 	if (!bus)
129 		goto failed;
130 
131 	virtfn = pci_alloc_dev(bus);
132 	if (!virtfn)
133 		goto failed0;
134 
135 	virtfn->devfn = pci_iov_virtfn_devfn(dev, id);
136 	virtfn->vendor = dev->vendor;
137 	virtfn->device = iov->vf_device;
138 	rc = pci_setup_device(virtfn);
139 	if (rc)
140 		goto failed0;
141 
142 	virtfn->dev.parent = dev->dev.parent;
143 	virtfn->physfn = pci_dev_get(dev);
144 	virtfn->is_virtfn = 1;
145 	virtfn->multifunction = 0;
146 
147 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
148 		res = &dev->resource[i + PCI_IOV_RESOURCES];
149 		if (!res->parent)
150 			continue;
151 		virtfn->resource[i].name = pci_name(virtfn);
152 		virtfn->resource[i].flags = res->flags;
153 		size = pci_iov_resource_size(dev, i + PCI_IOV_RESOURCES);
154 		virtfn->resource[i].start = res->start + size * id;
155 		virtfn->resource[i].end = virtfn->resource[i].start + size - 1;
156 		rc = request_resource(res, &virtfn->resource[i]);
157 		BUG_ON(rc);
158 	}
159 
160 	pci_device_add(virtfn, virtfn->bus);
161 
162 	sprintf(buf, "virtfn%u", id);
163 	rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
164 	if (rc)
165 		goto failed1;
166 	rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
167 	if (rc)
168 		goto failed2;
169 
170 	kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
171 
172 	pci_bus_add_device(virtfn);
173 
174 	return 0;
175 
176 failed2:
177 	sysfs_remove_link(&dev->dev.kobj, buf);
178 failed1:
179 	pci_dev_put(dev);
180 	pci_stop_and_remove_bus_device(virtfn);
181 failed0:
182 	virtfn_remove_bus(dev->bus, bus);
183 failed:
184 
185 	return rc;
186 }
187 
188 void pci_iov_remove_virtfn(struct pci_dev *dev, int id)
189 {
190 	char buf[VIRTFN_ID_LEN];
191 	struct pci_dev *virtfn;
192 
193 	virtfn = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus),
194 					     pci_iov_virtfn_bus(dev, id),
195 					     pci_iov_virtfn_devfn(dev, id));
196 	if (!virtfn)
197 		return;
198 
199 	sprintf(buf, "virtfn%u", id);
200 	sysfs_remove_link(&dev->dev.kobj, buf);
201 	/*
202 	 * pci_stop_dev() could have been called for this virtfn already,
203 	 * so the directory for the virtfn may have been removed before.
204 	 * Double check to avoid spurious sysfs warnings.
205 	 */
206 	if (virtfn->dev.kobj.sd)
207 		sysfs_remove_link(&virtfn->dev.kobj, "physfn");
208 
209 	pci_stop_and_remove_bus_device(virtfn);
210 	virtfn_remove_bus(dev->bus, virtfn->bus);
211 
212 	/* balance pci_get_domain_bus_and_slot() */
213 	pci_dev_put(virtfn);
214 	pci_dev_put(dev);
215 }
216 
217 int __weak pcibios_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
218 {
219 	return 0;
220 }
221 
222 int __weak pcibios_sriov_disable(struct pci_dev *pdev)
223 {
224 	return 0;
225 }
226 
227 static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
228 {
229 	int rc;
230 	int i;
231 	int nres;
232 	u16 initial;
233 	struct resource *res;
234 	struct pci_dev *pdev;
235 	struct pci_sriov *iov = dev->sriov;
236 	int bars = 0;
237 	int bus;
238 
239 	if (!nr_virtfn)
240 		return 0;
241 
242 	if (iov->num_VFs)
243 		return -EINVAL;
244 
245 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_INITIAL_VF, &initial);
246 	if (initial > iov->total_VFs ||
247 	    (!(iov->cap & PCI_SRIOV_CAP_VFM) && (initial != iov->total_VFs)))
248 		return -EIO;
249 
250 	if (nr_virtfn < 0 || nr_virtfn > iov->total_VFs ||
251 	    (!(iov->cap & PCI_SRIOV_CAP_VFM) && (nr_virtfn > initial)))
252 		return -EINVAL;
253 
254 	nres = 0;
255 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
256 		bars |= (1 << (i + PCI_IOV_RESOURCES));
257 		res = &dev->resource[i + PCI_IOV_RESOURCES];
258 		if (res->parent)
259 			nres++;
260 	}
261 	if (nres != iov->nres) {
262 		dev_err(&dev->dev, "not enough MMIO resources for SR-IOV\n");
263 		return -ENOMEM;
264 	}
265 
266 	bus = pci_iov_virtfn_bus(dev, nr_virtfn - 1);
267 	if (bus > dev->bus->busn_res.end) {
268 		dev_err(&dev->dev, "can't enable %d VFs (bus %02x out of range of %pR)\n",
269 			nr_virtfn, bus, &dev->bus->busn_res);
270 		return -ENOMEM;
271 	}
272 
273 	if (pci_enable_resources(dev, bars)) {
274 		dev_err(&dev->dev, "SR-IOV: IOV BARS not allocated\n");
275 		return -ENOMEM;
276 	}
277 
278 	if (iov->link != dev->devfn) {
279 		pdev = pci_get_slot(dev->bus, iov->link);
280 		if (!pdev)
281 			return -ENODEV;
282 
283 		if (!pdev->is_physfn) {
284 			pci_dev_put(pdev);
285 			return -ENOSYS;
286 		}
287 
288 		rc = sysfs_create_link(&dev->dev.kobj,
289 					&pdev->dev.kobj, "dep_link");
290 		pci_dev_put(pdev);
291 		if (rc)
292 			return rc;
293 	}
294 
295 	iov->initial_VFs = initial;
296 	if (nr_virtfn < initial)
297 		initial = nr_virtfn;
298 
299 	rc = pcibios_sriov_enable(dev, initial);
300 	if (rc) {
301 		dev_err(&dev->dev, "failure %d from pcibios_sriov_enable()\n", rc);
302 		goto err_pcibios;
303 	}
304 
305 	pci_iov_set_numvfs(dev, nr_virtfn);
306 	iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
307 	pci_cfg_access_lock(dev);
308 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
309 	msleep(100);
310 	pci_cfg_access_unlock(dev);
311 
312 	for (i = 0; i < initial; i++) {
313 		rc = pci_iov_add_virtfn(dev, i);
314 		if (rc)
315 			goto failed;
316 	}
317 
318 	kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
319 	iov->num_VFs = nr_virtfn;
320 
321 	return 0;
322 
323 failed:
324 	while (i--)
325 		pci_iov_remove_virtfn(dev, i);
326 
327 err_pcibios:
328 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
329 	pci_cfg_access_lock(dev);
330 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
331 	ssleep(1);
332 	pci_cfg_access_unlock(dev);
333 
334 	pcibios_sriov_disable(dev);
335 
336 	if (iov->link != dev->devfn)
337 		sysfs_remove_link(&dev->dev.kobj, "dep_link");
338 
339 	pci_iov_set_numvfs(dev, 0);
340 	return rc;
341 }
342 
343 static void sriov_disable(struct pci_dev *dev)
344 {
345 	int i;
346 	struct pci_sriov *iov = dev->sriov;
347 
348 	if (!iov->num_VFs)
349 		return;
350 
351 	for (i = 0; i < iov->num_VFs; i++)
352 		pci_iov_remove_virtfn(dev, i);
353 
354 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
355 	pci_cfg_access_lock(dev);
356 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
357 	ssleep(1);
358 	pci_cfg_access_unlock(dev);
359 
360 	pcibios_sriov_disable(dev);
361 
362 	if (iov->link != dev->devfn)
363 		sysfs_remove_link(&dev->dev.kobj, "dep_link");
364 
365 	iov->num_VFs = 0;
366 	pci_iov_set_numvfs(dev, 0);
367 }
368 
369 static int sriov_init(struct pci_dev *dev, int pos)
370 {
371 	int i, bar64;
372 	int rc;
373 	int nres;
374 	u32 pgsz;
375 	u16 ctrl, total;
376 	struct pci_sriov *iov;
377 	struct resource *res;
378 	struct pci_dev *pdev;
379 
380 	pci_read_config_word(dev, pos + PCI_SRIOV_CTRL, &ctrl);
381 	if (ctrl & PCI_SRIOV_CTRL_VFE) {
382 		pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, 0);
383 		ssleep(1);
384 	}
385 
386 	ctrl = 0;
387 	list_for_each_entry(pdev, &dev->bus->devices, bus_list)
388 		if (pdev->is_physfn)
389 			goto found;
390 
391 	pdev = NULL;
392 	if (pci_ari_enabled(dev->bus))
393 		ctrl |= PCI_SRIOV_CTRL_ARI;
394 
395 found:
396 	pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
397 
398 	pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total);
399 	if (!total)
400 		return 0;
401 
402 	pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
403 	i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
404 	pgsz &= ~((1 << i) - 1);
405 	if (!pgsz)
406 		return -EIO;
407 
408 	pgsz &= ~(pgsz - 1);
409 	pci_write_config_dword(dev, pos + PCI_SRIOV_SYS_PGSIZE, pgsz);
410 
411 	iov = kzalloc(sizeof(*iov), GFP_KERNEL);
412 	if (!iov)
413 		return -ENOMEM;
414 
415 	nres = 0;
416 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
417 		res = &dev->resource[i + PCI_IOV_RESOURCES];
418 		/*
419 		 * If it is already FIXED, don't change it, something
420 		 * (perhaps EA or header fixups) wants it this way.
421 		 */
422 		if (res->flags & IORESOURCE_PCI_FIXED)
423 			bar64 = (res->flags & IORESOURCE_MEM_64) ? 1 : 0;
424 		else
425 			bar64 = __pci_read_base(dev, pci_bar_unknown, res,
426 						pos + PCI_SRIOV_BAR + i * 4);
427 		if (!res->flags)
428 			continue;
429 		if (resource_size(res) & (PAGE_SIZE - 1)) {
430 			rc = -EIO;
431 			goto failed;
432 		}
433 		iov->barsz[i] = resource_size(res);
434 		res->end = res->start + resource_size(res) * total - 1;
435 		dev_info(&dev->dev, "VF(n) BAR%d space: %pR (contains BAR%d for %d VFs)\n",
436 			 i, res, i, total);
437 		i += bar64;
438 		nres++;
439 	}
440 
441 	iov->pos = pos;
442 	iov->nres = nres;
443 	iov->ctrl = ctrl;
444 	iov->total_VFs = total;
445 	pci_read_config_word(dev, pos + PCI_SRIOV_VF_DID, &iov->vf_device);
446 	iov->pgsz = pgsz;
447 	iov->self = dev;
448 	iov->drivers_autoprobe = true;
449 	pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
450 	pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
451 	if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
452 		iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);
453 
454 	if (pdev)
455 		iov->dev = pci_dev_get(pdev);
456 	else
457 		iov->dev = dev;
458 
459 	dev->sriov = iov;
460 	dev->is_physfn = 1;
461 	rc = compute_max_vf_buses(dev);
462 	if (rc)
463 		goto fail_max_buses;
464 
465 	return 0;
466 
467 fail_max_buses:
468 	dev->sriov = NULL;
469 	dev->is_physfn = 0;
470 failed:
471 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
472 		res = &dev->resource[i + PCI_IOV_RESOURCES];
473 		res->flags = 0;
474 	}
475 
476 	kfree(iov);
477 	return rc;
478 }
479 
480 static void sriov_release(struct pci_dev *dev)
481 {
482 	BUG_ON(dev->sriov->num_VFs);
483 
484 	if (dev != dev->sriov->dev)
485 		pci_dev_put(dev->sriov->dev);
486 
487 	kfree(dev->sriov);
488 	dev->sriov = NULL;
489 }
490 
491 static void sriov_restore_state(struct pci_dev *dev)
492 {
493 	int i;
494 	u16 ctrl;
495 	struct pci_sriov *iov = dev->sriov;
496 
497 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &ctrl);
498 	if (ctrl & PCI_SRIOV_CTRL_VFE)
499 		return;
500 
501 	/*
502 	 * Restore PCI_SRIOV_CTRL_ARI before pci_iov_set_numvfs() because
503 	 * it reads offset & stride, which depend on PCI_SRIOV_CTRL_ARI.
504 	 */
505 	ctrl &= ~PCI_SRIOV_CTRL_ARI;
506 	ctrl |= iov->ctrl & PCI_SRIOV_CTRL_ARI;
507 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, ctrl);
508 
509 	for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++)
510 		pci_update_resource(dev, i);
511 
512 	pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
513 	pci_iov_set_numvfs(dev, iov->num_VFs);
514 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
515 	if (iov->ctrl & PCI_SRIOV_CTRL_VFE)
516 		msleep(100);
517 }
518 
519 /**
520  * pci_iov_init - initialize the IOV capability
521  * @dev: the PCI device
522  *
523  * Returns 0 on success, or negative on failure.
524  */
525 int pci_iov_init(struct pci_dev *dev)
526 {
527 	int pos;
528 
529 	if (!pci_is_pcie(dev))
530 		return -ENODEV;
531 
532 	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
533 	if (pos)
534 		return sriov_init(dev, pos);
535 
536 	return -ENODEV;
537 }
538 
539 /**
540  * pci_iov_release - release resources used by the IOV capability
541  * @dev: the PCI device
542  */
543 void pci_iov_release(struct pci_dev *dev)
544 {
545 	if (dev->is_physfn)
546 		sriov_release(dev);
547 }
548 
549 /**
550  * pci_iov_update_resource - update a VF BAR
551  * @dev: the PCI device
552  * @resno: the resource number
553  *
554  * Update a VF BAR in the SR-IOV capability of a PF.
555  */
556 void pci_iov_update_resource(struct pci_dev *dev, int resno)
557 {
558 	struct pci_sriov *iov = dev->is_physfn ? dev->sriov : NULL;
559 	struct resource *res = dev->resource + resno;
560 	int vf_bar = resno - PCI_IOV_RESOURCES;
561 	struct pci_bus_region region;
562 	u16 cmd;
563 	u32 new;
564 	int reg;
565 
566 	/*
567 	 * The generic pci_restore_bars() path calls this for all devices,
568 	 * including VFs and non-SR-IOV devices.  If this is not a PF, we
569 	 * have nothing to do.
570 	 */
571 	if (!iov)
572 		return;
573 
574 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &cmd);
575 	if ((cmd & PCI_SRIOV_CTRL_VFE) && (cmd & PCI_SRIOV_CTRL_MSE)) {
576 		dev_WARN(&dev->dev, "can't update enabled VF BAR%d %pR\n",
577 			 vf_bar, res);
578 		return;
579 	}
580 
581 	/*
582 	 * Ignore unimplemented BARs, unused resource slots for 64-bit
583 	 * BARs, and non-movable resources, e.g., those described via
584 	 * Enhanced Allocation.
585 	 */
586 	if (!res->flags)
587 		return;
588 
589 	if (res->flags & IORESOURCE_UNSET)
590 		return;
591 
592 	if (res->flags & IORESOURCE_PCI_FIXED)
593 		return;
594 
595 	pcibios_resource_to_bus(dev->bus, &region, res);
596 	new = region.start;
597 	new |= res->flags & ~PCI_BASE_ADDRESS_MEM_MASK;
598 
599 	reg = iov->pos + PCI_SRIOV_BAR + 4 * vf_bar;
600 	pci_write_config_dword(dev, reg, new);
601 	if (res->flags & IORESOURCE_MEM_64) {
602 		new = region.start >> 16 >> 16;
603 		pci_write_config_dword(dev, reg + 4, new);
604 	}
605 }
606 
607 resource_size_t __weak pcibios_iov_resource_alignment(struct pci_dev *dev,
608 						      int resno)
609 {
610 	return pci_iov_resource_size(dev, resno);
611 }
612 
613 /**
614  * pci_sriov_resource_alignment - get resource alignment for VF BAR
615  * @dev: the PCI device
616  * @resno: the resource number
617  *
618  * Returns the alignment of the VF BAR found in the SR-IOV capability.
619  * This is not the same as the resource size which is defined as
620  * the VF BAR size multiplied by the number of VFs.  The alignment
621  * is just the VF BAR size.
622  */
623 resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
624 {
625 	return pcibios_iov_resource_alignment(dev, resno);
626 }
627 
628 /**
629  * pci_restore_iov_state - restore the state of the IOV capability
630  * @dev: the PCI device
631  */
632 void pci_restore_iov_state(struct pci_dev *dev)
633 {
634 	if (dev->is_physfn)
635 		sriov_restore_state(dev);
636 }
637 
638 /**
639  * pci_iov_bus_range - find bus range used by Virtual Function
640  * @bus: the PCI bus
641  *
642  * Returns max number of buses (exclude current one) used by Virtual
643  * Functions.
644  */
645 int pci_iov_bus_range(struct pci_bus *bus)
646 {
647 	int max = 0;
648 	struct pci_dev *dev;
649 
650 	list_for_each_entry(dev, &bus->devices, bus_list) {
651 		if (!dev->is_physfn)
652 			continue;
653 		if (dev->sriov->max_VF_buses > max)
654 			max = dev->sriov->max_VF_buses;
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 -ENOSYS;
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_num_vf - return number of VFs associated with a PF device_release_driver
695  * @dev: the PCI device
696  *
697  * Returns number of VFs, or 0 if SR-IOV is not enabled.
698  */
699 int pci_num_vf(struct pci_dev *dev)
700 {
701 	if (!dev->is_physfn)
702 		return 0;
703 
704 	return dev->sriov->num_VFs;
705 }
706 EXPORT_SYMBOL_GPL(pci_num_vf);
707 
708 /**
709  * pci_vfs_assigned - returns number of VFs are assigned to a guest
710  * @dev: the PCI device
711  *
712  * Returns number of VFs belonging to this device that are assigned to a guest.
713  * If device is not a physical function returns 0.
714  */
715 int pci_vfs_assigned(struct pci_dev *dev)
716 {
717 	struct pci_dev *vfdev;
718 	unsigned int vfs_assigned = 0;
719 	unsigned short dev_id;
720 
721 	/* only search if we are a PF */
722 	if (!dev->is_physfn)
723 		return 0;
724 
725 	/*
726 	 * determine the device ID for the VFs, the vendor ID will be the
727 	 * same as the PF so there is no need to check for that one
728 	 */
729 	dev_id = dev->sriov->vf_device;
730 
731 	/* loop through all the VFs to see if we own any that are assigned */
732 	vfdev = pci_get_device(dev->vendor, dev_id, NULL);
733 	while (vfdev) {
734 		/*
735 		 * It is considered assigned if it is a virtual function with
736 		 * our dev as the physical function and the assigned bit is set
737 		 */
738 		if (vfdev->is_virtfn && (vfdev->physfn == dev) &&
739 			pci_is_dev_assigned(vfdev))
740 			vfs_assigned++;
741 
742 		vfdev = pci_get_device(dev->vendor, dev_id, vfdev);
743 	}
744 
745 	return vfs_assigned;
746 }
747 EXPORT_SYMBOL_GPL(pci_vfs_assigned);
748 
749 /**
750  * pci_sriov_set_totalvfs -- reduce the TotalVFs available
751  * @dev: the PCI PF device
752  * @numvfs: number that should be used for TotalVFs supported
753  *
754  * Should be called from PF driver's probe routine with
755  * device's mutex held.
756  *
757  * Returns 0 if PF is an SRIOV-capable device and
758  * value of numvfs valid. If not a PF return -ENOSYS;
759  * if numvfs is invalid return -EINVAL;
760  * if VFs already enabled, return -EBUSY.
761  */
762 int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
763 {
764 	if (!dev->is_physfn)
765 		return -ENOSYS;
766 	if (numvfs > dev->sriov->total_VFs)
767 		return -EINVAL;
768 
769 	/* Shouldn't change if VFs already enabled */
770 	if (dev->sriov->ctrl & PCI_SRIOV_CTRL_VFE)
771 		return -EBUSY;
772 	else
773 		dev->sriov->driver_max_VFs = numvfs;
774 
775 	return 0;
776 }
777 EXPORT_SYMBOL_GPL(pci_sriov_set_totalvfs);
778 
779 /**
780  * pci_sriov_get_totalvfs -- get total VFs supported on this device
781  * @dev: the PCI PF device
782  *
783  * For a PCIe device with SRIOV support, return the PCIe
784  * SRIOV capability value of TotalVFs or the value of driver_max_VFs
785  * if the driver reduced it.  Otherwise 0.
786  */
787 int pci_sriov_get_totalvfs(struct pci_dev *dev)
788 {
789 	if (!dev->is_physfn)
790 		return 0;
791 
792 	if (dev->sriov->driver_max_VFs)
793 		return dev->sriov->driver_max_VFs;
794 
795 	return dev->sriov->total_VFs;
796 }
797 EXPORT_SYMBOL_GPL(pci_sriov_get_totalvfs);
798