drivers/pci/iov.c

   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, int reset)
 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         mutex_lock(&iov->dev->sriov->lock);
 128         bus = virtfn_add_bus(dev->bus, pci_iov_virtfn_bus(dev, id));
 129         if (!bus)
 130                 goto failed;
 131
 132         virtfn = pci_alloc_dev(bus);
 133         if (!virtfn)
 134                 goto failed0;
 135
 136         virtfn->devfn = pci_iov_virtfn_devfn(dev, id);
 137         virtfn->vendor = dev->vendor;
 138         pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_DID, &virtfn->device);
 139         pci_setup_device(virtfn);
 140         virtfn->dev.parent = dev->dev.parent;
 141         virtfn->physfn = pci_dev_get(dev);
 142         virtfn->is_virtfn = 1;
 143         virtfn->multifunction = 0;
 144
 145         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 146                 res = &dev->resource[i + PCI_IOV_RESOURCES];
 147                 if (!res->parent)
 148                         continue;
 149                 virtfn->resource[i].name = pci_name(virtfn);
 150                 virtfn->resource[i].flags = res->flags;
 151                 size = pci_iov_resource_size(dev, i + PCI_IOV_RESOURCES);
 152                 virtfn->resource[i].start = res->start + size * id;
 153                 virtfn->resource[i].end = virtfn->resource[i].start + size - 1;
 154                 rc = request_resource(res, &virtfn->resource[i]);
 155                 BUG_ON(rc);
 156         }
 157
 158         if (reset)
 159                 __pci_reset_function(virtfn);
 160
 161         pci_device_add(virtfn, virtfn->bus);
 162         mutex_unlock(&iov->dev->sriov->lock);
 163
 164         pci_bus_add_device(virtfn);
 165         sprintf(buf, "virtfn%u", id);
 166         rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
 167         if (rc)
 168                 goto failed1;
 169         rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
 170         if (rc)
 171                 goto failed2;
 172
 173         kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
 174
 175         return 0;
 176
 177 failed2:
 178         sysfs_remove_link(&dev->dev.kobj, buf);
 179 failed1:
 180         pci_dev_put(dev);
 181         mutex_lock(&iov->dev->sriov->lock);
 182         pci_stop_and_remove_bus_device(virtfn);
 183 failed0:
 184         virtfn_remove_bus(dev->bus, bus);
 185 failed:
 186         mutex_unlock(&iov->dev->sriov->lock);
 187
 188         return rc;
 189 }
 190
 191 void pci_iov_remove_virtfn(struct pci_dev *dev, int id, int reset)
 192 {
 193         char buf[VIRTFN_ID_LEN];
 194         struct pci_dev *virtfn;
 195         struct pci_sriov *iov = dev->sriov;
 196
 197         virtfn = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus),
 198                                              pci_iov_virtfn_bus(dev, id),
 199                                              pci_iov_virtfn_devfn(dev, id));
 200         if (!virtfn)
 201                 return;
 202
 203         if (reset) {
 204                 device_release_driver(&virtfn->dev);
 205                 __pci_reset_function(virtfn);
 206         }
 207
 208         sprintf(buf, "virtfn%u", id);
 209         sysfs_remove_link(&dev->dev.kobj, buf);
 210         /*
 211          * pci_stop_dev() could have been called for this virtfn already,
 212          * so the directory for the virtfn may have been removed before.
 213          * Double check to avoid spurious sysfs warnings.
 214          */
 215         if (virtfn->dev.kobj.sd)
 216                 sysfs_remove_link(&virtfn->dev.kobj, "physfn");
 217
 218         mutex_lock(&iov->dev->sriov->lock);
 219         pci_stop_and_remove_bus_device(virtfn);
 220         virtfn_remove_bus(dev->bus, virtfn->bus);
 221         mutex_unlock(&iov->dev->sriov->lock);
 222
 223         /* balance pci_get_domain_bus_and_slot() */
 224         pci_dev_put(virtfn);
 225         pci_dev_put(dev);
 226 }
 227
 228 int __weak pcibios_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
 229 {
 230         return 0;
 231 }
 232
 233 int __weak pcibios_sriov_disable(struct pci_dev *pdev)
 234 {
 235         return 0;
 236 }
 237
 238 static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 239 {
 240         int rc;
 241         int i;
 242         int nres;
 243         u16 initial;
 244         struct resource *res;
 245         struct pci_dev *pdev;
 246         struct pci_sriov *iov = dev->sriov;
 247         int bars = 0;
 248         int bus;
 249
 250         if (!nr_virtfn)
 251                 return 0;
 252
 253         if (iov->num_VFs)
 254                 return -EINVAL;
 255
 256         pci_read_config_word(dev, iov->pos + PCI_SRIOV_INITIAL_VF, &initial);
 257         if (initial > iov->total_VFs ||
 258             (!(iov->cap & PCI_SRIOV_CAP_VFM) && (initial != iov->total_VFs)))
 259                 return -EIO;
 260
 261         if (nr_virtfn < 0 || nr_virtfn > iov->total_VFs ||
 262             (!(iov->cap & PCI_SRIOV_CAP_VFM) && (nr_virtfn > initial)))
 263                 return -EINVAL;
 264
 265         nres = 0;
 266         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 267                 bars |= (1 << (i + PCI_IOV_RESOURCES));
 268                 res = &dev->resource[i + PCI_IOV_RESOURCES];
 269                 if (res->parent)
 270                         nres++;
 271         }
 272         if (nres != iov->nres) {
 273                 dev_err(&dev->dev, "not enough MMIO resources for SR-IOV\n");
 274                 return -ENOMEM;
 275         }
 276
 277         bus = pci_iov_virtfn_bus(dev, nr_virtfn - 1);
 278         if (bus > dev->bus->busn_res.end) {
 279                 dev_err(&dev->dev, "can't enable %d VFs (bus %02x out of range of %pR)\n",
 280                         nr_virtfn, bus, &dev->bus->busn_res);
 281                 return -ENOMEM;
 282         }
 283
 284         if (pci_enable_resources(dev, bars)) {
 285                 dev_err(&dev->dev, "SR-IOV: IOV BARS not allocated\n");
 286                 return -ENOMEM;
 287         }
 288
 289         if (iov->link != dev->devfn) {
 290                 pdev = pci_get_slot(dev->bus, iov->link);
 291                 if (!pdev)
 292                         return -ENODEV;
 293
 294                 if (!pdev->is_physfn) {
 295                         pci_dev_put(pdev);
 296                         return -ENOSYS;
 297                 }
 298
 299                 rc = sysfs_create_link(&dev->dev.kobj,
 300                                         &pdev->dev.kobj, "dep_link");
 301                 pci_dev_put(pdev);
 302                 if (rc)
 303                         return rc;
 304         }
 305
 306         pci_iov_set_numvfs(dev, nr_virtfn);
 307         iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
 308         pci_cfg_access_lock(dev);
 309         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 310         msleep(100);
 311         pci_cfg_access_unlock(dev);
 312
 313         iov->initial_VFs = initial;
 314         if (nr_virtfn < initial)
 315                 initial = nr_virtfn;
 316
 317         rc = pcibios_sriov_enable(dev, initial);
 318         if (rc) {
 319                 dev_err(&dev->dev, "failure %d from pcibios_sriov_enable()\n", rc);
 320                 goto err_pcibios;
 321         }
 322
 323         for (i = 0; i < initial; i++) {
 324                 rc = pci_iov_add_virtfn(dev, i, 0);
 325                 if (rc)
 326                         goto failed;
 327         }
 328
 329         kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
 330         iov->num_VFs = nr_virtfn;
 331
 332         return 0;
 333
 334 failed:
 335         while (i--)
 336                 pci_iov_remove_virtfn(dev, i, 0);
 337
 338         pcibios_sriov_disable(dev);
 339 err_pcibios:
 340         iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 341         pci_cfg_access_lock(dev);
 342         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 343         ssleep(1);
 344         pci_cfg_access_unlock(dev);
 345
 346         if (iov->link != dev->devfn)
 347                 sysfs_remove_link(&dev->dev.kobj, "dep_link");
 348
 349         pci_iov_set_numvfs(dev, 0);
 350         return rc;
 351 }
 352
 353 static void sriov_disable(struct pci_dev *dev)
 354 {
 355         int i;
 356         struct pci_sriov *iov = dev->sriov;
 357
 358         if (!iov->num_VFs)
 359                 return;
 360
 361         for (i = 0; i < iov->num_VFs; i++)
 362                 pci_iov_remove_virtfn(dev, i, 0);
 363
 364         pcibios_sriov_disable(dev);
 365
 366         iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 367         pci_cfg_access_lock(dev);
 368         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 369         ssleep(1);
 370         pci_cfg_access_unlock(dev);
 371
 372         if (iov->link != dev->devfn)
 373                 sysfs_remove_link(&dev->dev.kobj, "dep_link");
 374
 375         iov->num_VFs = 0;
 376         pci_iov_set_numvfs(dev, 0);
 377 }
 378
 379 static int sriov_init(struct pci_dev *dev, int pos)
 380 {
 381         int i, bar64;
 382         int rc;
 383         int nres;
 384         u32 pgsz;
 385         u16 ctrl, total;
 386         struct pci_sriov *iov;
 387         struct resource *res;
 388         struct pci_dev *pdev;
 389
 390         pci_read_config_word(dev, pos + PCI_SRIOV_CTRL, &ctrl);
 391         if (ctrl & PCI_SRIOV_CTRL_VFE) {
 392                 pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, 0);
 393                 ssleep(1);
 394         }
 395
 396         ctrl = 0;
 397         list_for_each_entry(pdev, &dev->bus->devices, bus_list)
 398                 if (pdev->is_physfn)
 399                         goto found;
 400
 401         pdev = NULL;
 402         if (pci_ari_enabled(dev->bus))
 403                 ctrl |= PCI_SRIOV_CTRL_ARI;
 404
 405 found:
 406         pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
 407
 408         pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total);
 409         if (!total)
 410                 return 0;
 411
 412         pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
 413         i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
 414         pgsz &= ~((1 << i) - 1);
 415         if (!pgsz)
 416                 return -EIO;
 417
 418         pgsz &= ~(pgsz - 1);
 419         pci_write_config_dword(dev, pos + PCI_SRIOV_SYS_PGSIZE, pgsz);
 420
 421         iov = kzalloc(sizeof(*iov), GFP_KERNEL);
 422         if (!iov)
 423                 return -ENOMEM;
 424
 425         nres = 0;
 426         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 427                 res = &dev->resource[i + PCI_IOV_RESOURCES];
 428                 /*
 429                  * If it is already FIXED, don't change it, something
 430                  * (perhaps EA or header fixups) wants it this way.
 431                  */
 432                 if (res->flags & IORESOURCE_PCI_FIXED)
 433                         bar64 = (res->flags & IORESOURCE_MEM_64) ? 1 : 0;
 434                 else
 435                         bar64 = __pci_read_base(dev, pci_bar_unknown, res,
 436                                                 pos + PCI_SRIOV_BAR + i * 4);
 437                 if (!res->flags)
 438                         continue;
 439                 if (resource_size(res) & (PAGE_SIZE - 1)) {
 440                         rc = -EIO;
 441                         goto failed;
 442                 }
 443                 iov->barsz[i] = resource_size(res);
 444                 res->end = res->start + resource_size(res) * total - 1;
 445                 dev_info(&dev->dev, "VF(n) BAR%d space: %pR (contains BAR%d for %d VFs)\n",
 446                          i, res, i, total);
 447                 i += bar64;
 448                 nres++;
 449         }
 450
 451         iov->pos = pos;
 452         iov->nres = nres;
 453         iov->ctrl = ctrl;
 454         iov->total_VFs = total;
 455         iov->pgsz = pgsz;
 456         iov->self = dev;
 457         pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
 458         pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
 459         if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
 460                 iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);
 461
 462         if (pdev)
 463                 iov->dev = pci_dev_get(pdev);
 464         else
 465                 iov->dev = dev;
 466
 467         mutex_init(&iov->lock);
 468
 469         dev->sriov = iov;
 470         dev->is_physfn = 1;
 471         rc = compute_max_vf_buses(dev);
 472         if (rc)
 473                 goto fail_max_buses;
 474
 475         return 0;
 476
 477 fail_max_buses:
 478         dev->sriov = NULL;
 479         dev->is_physfn = 0;
 480 failed:
 481         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 482                 res = &dev->resource[i + PCI_IOV_RESOURCES];
 483                 res->flags = 0;
 484         }
 485
 486         kfree(iov);
 487         return rc;
 488 }
 489
 490 static void sriov_release(struct pci_dev *dev)
 491 {
 492         BUG_ON(dev->sriov->num_VFs);
 493
 494         if (dev != dev->sriov->dev)
 495                 pci_dev_put(dev->sriov->dev);
 496
 497         mutex_destroy(&dev->sriov->lock);
 498
 499         kfree(dev->sriov);
 500         dev->sriov = NULL;
 501 }
 502
 503 static void sriov_restore_state(struct pci_dev *dev)
 504 {
 505         int i;
 506         u16 ctrl;
 507         struct pci_sriov *iov = dev->sriov;
 508
 509         pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &ctrl);
 510         if (ctrl & PCI_SRIOV_CTRL_VFE)
 511                 return;
 512
 513         for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++)
 514                 pci_update_resource(dev, i);
 515
 516         pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
 517         pci_iov_set_numvfs(dev, iov->num_VFs);
 518         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 519         if (iov->ctrl & PCI_SRIOV_CTRL_VFE)
 520                 msleep(100);
 521 }
 522
 523 /**
 524  * pci_iov_init - initialize the IOV capability
 525  * @dev: the PCI device
 526  *
 527  * Returns 0 on success, or negative on failure.
 528  */
 529 int pci_iov_init(struct pci_dev *dev)
 530 {
 531         int pos;
 532
 533         if (!pci_is_pcie(dev))
 534                 return -ENODEV;
 535
 536         pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
 537         if (pos)
 538                 return sriov_init(dev, pos);
 539
 540         return -ENODEV;
 541 }
 542
 543 /**
 544  * pci_iov_release - release resources used by the IOV capability
 545  * @dev: the PCI device
 546  */
 547 void pci_iov_release(struct pci_dev *dev)
 548 {
 549         if (dev->is_physfn)
 550                 sriov_release(dev);
 551 }
 552
 553 /**
 554  * pci_iov_resource_bar - get position of the SR-IOV BAR
 555  * @dev: the PCI device
 556  * @resno: the resource number
 557  *
 558  * Returns position of the BAR encapsulated in the SR-IOV capability.
 559  */
 560 int pci_iov_resource_bar(struct pci_dev *dev, int resno)
 561 {
 562         if (resno < PCI_IOV_RESOURCES || resno > PCI_IOV_RESOURCE_END)
 563                 return 0;
 564
 565         BUG_ON(!dev->is_physfn);
 566
 567         return dev->sriov->pos + PCI_SRIOV_BAR +
 568                 4 * (resno - PCI_IOV_RESOURCES);
 569 }
 570
 571 resource_size_t __weak pcibios_iov_resource_alignment(struct pci_dev *dev,
 572                                                       int resno)
 573 {
 574         return pci_iov_resource_size(dev, resno);
 575 }
 576
 577 /**
 578  * pci_sriov_resource_alignment - get resource alignment for VF BAR
 579  * @dev: the PCI device
 580  * @resno: the resource number
 581  *
 582  * Returns the alignment of the VF BAR found in the SR-IOV capability.
 583  * This is not the same as the resource size which is defined as
 584  * the VF BAR size multiplied by the number of VFs.  The alignment
 585  * is just the VF BAR size.
 586  */
 587 resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
 588 {
 589         return pcibios_iov_resource_alignment(dev, resno);
 590 }
 591
 592 /**
 593  * pci_restore_iov_state - restore the state of the IOV capability
 594  * @dev: the PCI device
 595  */
 596 void pci_restore_iov_state(struct pci_dev *dev)
 597 {
 598         if (dev->is_physfn)
 599                 sriov_restore_state(dev);
 600 }
 601
 602 /**
 603  * pci_iov_bus_range - find bus range used by Virtual Function
 604  * @bus: the PCI bus
 605  *
 606  * Returns max number of buses (exclude current one) used by Virtual
 607  * Functions.
 608  */
 609 int pci_iov_bus_range(struct pci_bus *bus)
 610 {
 611         int max = 0;
 612         struct pci_dev *dev;
 613
 614         list_for_each_entry(dev, &bus->devices, bus_list) {
 615                 if (!dev->is_physfn)
 616                         continue;
 617                 if (dev->sriov->max_VF_buses > max)
 618                         max = dev->sriov->max_VF_buses;
 619         }
 620
 621         return max ? max - bus->number : 0;
 622 }
 623
 624 /**
 625  * pci_enable_sriov - enable the SR-IOV capability
 626  * @dev: the PCI device
 627  * @nr_virtfn: number of virtual functions to enable
 628  *
 629  * Returns 0 on success, or negative on failure.
 630  */
 631 int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
 632 {
 633         might_sleep();
 634
 635         if (!dev->is_physfn)
 636                 return -ENOSYS;
 637
 638         return sriov_enable(dev, nr_virtfn);
 639 }
 640 EXPORT_SYMBOL_GPL(pci_enable_sriov);
 641
 642 /**
 643  * pci_disable_sriov - disable the SR-IOV capability
 644  * @dev: the PCI device
 645  */
 646 void pci_disable_sriov(struct pci_dev *dev)
 647 {
 648         might_sleep();
 649
 650         if (!dev->is_physfn)
 651                 return;
 652
 653         sriov_disable(dev);
 654 }
 655 EXPORT_SYMBOL_GPL(pci_disable_sriov);
 656
 657 /**
 658  * pci_num_vf - return number of VFs associated with a PF device_release_driver
 659  * @dev: the PCI device
 660  *
 661  * Returns number of VFs, or 0 if SR-IOV is not enabled.
 662  */
 663 int pci_num_vf(struct pci_dev *dev)
 664 {
 665         if (!dev->is_physfn)
 666                 return 0;
 667
 668         return dev->sriov->num_VFs;
 669 }
 670 EXPORT_SYMBOL_GPL(pci_num_vf);
 671
 672 /**
 673  * pci_vfs_assigned - returns number of VFs are assigned to a guest
 674  * @dev: the PCI device
 675  *
 676  * Returns number of VFs belonging to this device that are assigned to a guest.
 677  * If device is not a physical function returns 0.
 678  */
 679 int pci_vfs_assigned(struct pci_dev *dev)
 680 {
 681         struct pci_dev *vfdev;
 682         unsigned int vfs_assigned = 0;
 683         unsigned short dev_id;
 684
 685         /* only search if we are a PF */
 686         if (!dev->is_physfn)
 687                 return 0;
 688
 689         /*
 690          * determine the device ID for the VFs, the vendor ID will be the
 691          * same as the PF so there is no need to check for that one
 692          */
 693         pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_VF_DID, &dev_id);
 694
 695         /* loop through all the VFs to see if we own any that are assigned */
 696         vfdev = pci_get_device(dev->vendor, dev_id, NULL);
 697         while (vfdev) {
 698                 /*
 699                  * It is considered assigned if it is a virtual function with
 700                  * our dev as the physical function and the assigned bit is set
 701                  */
 702                 if (vfdev->is_virtfn && (vfdev->physfn == dev) &&
 703                         pci_is_dev_assigned(vfdev))
 704                         vfs_assigned++;
 705
 706                 vfdev = pci_get_device(dev->vendor, dev_id, vfdev);
 707         }
 708
 709         return vfs_assigned;
 710 }
 711 EXPORT_SYMBOL_GPL(pci_vfs_assigned);
 712
 713 /**
 714  * pci_sriov_set_totalvfs -- reduce the TotalVFs available
 715  * @dev: the PCI PF device
 716  * @numvfs: number that should be used for TotalVFs supported
 717  *
 718  * Should be called from PF driver's probe routine with
 719  * device's mutex held.
 720  *
 721  * Returns 0 if PF is an SRIOV-capable device and
 722  * value of numvfs valid. If not a PF return -ENOSYS;
 723  * if numvfs is invalid return -EINVAL;
 724  * if VFs already enabled, return -EBUSY.
 725  */
 726 int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
 727 {
 728         if (!dev->is_physfn)
 729                 return -ENOSYS;
 730         if (numvfs > dev->sriov->total_VFs)
 731                 return -EINVAL;
 732
 733         /* Shouldn't change if VFs already enabled */
 734         if (dev->sriov->ctrl & PCI_SRIOV_CTRL_VFE)
 735                 return -EBUSY;
 736         else
 737                 dev->sriov->driver_max_VFs = numvfs;
 738
 739         return 0;
 740 }
 741 EXPORT_SYMBOL_GPL(pci_sriov_set_totalvfs);
 742
 743 /**
 744  * pci_sriov_get_totalvfs -- get total VFs supported on this device
 745  * @dev: the PCI PF device
 746  *
 747  * For a PCIe device with SRIOV support, return the PCIe
 748  * SRIOV capability value of TotalVFs or the value of driver_max_VFs
 749  * if the driver reduced it.  Otherwise 0.
 750  */
 751 int pci_sriov_get_totalvfs(struct pci_dev *dev)
 752 {
 753         if (!dev->is_physfn)
 754                 return 0;
 755
 756         if (dev->sriov->driver_max_VFs)
 757                 return dev->sriov->driver_max_VFs;
 758
 759         return dev->sriov->total_VFs;
 760 }
 761 EXPORT_SYMBOL_GPL(pci_sriov_get_totalvfs);