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 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         struct pci_bus *child;
  37
  38         if (bus->number == busnr)
  39                 return bus;
  40
  41         child = pci_find_bus(pci_domain_nr(bus), busnr);
  42         if (child)
  43                 return child;
  44
  45         child = pci_add_new_bus(bus, NULL, busnr);
  46         if (!child)
  47                 return NULL;
  48
  49         pci_bus_insert_busn_res(child, busnr, busnr);
  50
  51         return child;
  52 }
  53
  54 static void virtfn_remove_bus(struct pci_bus *physbus, struct pci_bus *virtbus)
  55 {
  56         if (physbus != virtbus && list_empty(&virtbus->devices))
  57                 pci_remove_bus(virtbus);
  58 }
  59
  60 static int virtfn_add(struct pci_dev *dev, int id, int reset)
  61 {
  62         int i;
  63         int rc = -ENOMEM;
  64         u64 size;
  65         char buf[VIRTFN_ID_LEN];
  66         struct pci_dev *virtfn;
  67         struct resource *res;
  68         struct pci_sriov *iov = dev->sriov;
  69         struct pci_bus *bus;
  70
  71         mutex_lock(&iov->dev->sriov->lock);
  72         bus = virtfn_add_bus(dev->bus, virtfn_bus(dev, id));
  73         if (!bus)
  74                 goto failed;
  75
  76         virtfn = pci_alloc_dev(bus);
  77         if (!virtfn)
  78                 goto failed0;
  79
  80         virtfn->devfn = virtfn_devfn(dev, id);
  81         virtfn->vendor = dev->vendor;
  82         pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_DID, &virtfn->device);
  83         pci_setup_device(virtfn);
  84         virtfn->dev.parent = dev->dev.parent;
  85         virtfn->physfn = pci_dev_get(dev);
  86         virtfn->is_virtfn = 1;
  87         virtfn->multifunction = 0;
  88
  89         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
  90                 res = dev->resource + PCI_IOV_RESOURCES + i;
  91                 if (!res->parent)
  92                         continue;
  93                 virtfn->resource[i].name = pci_name(virtfn);
  94                 virtfn->resource[i].flags = res->flags;
  95                 size = resource_size(res);
  96                 do_div(size, iov->total_VFs);
  97                 virtfn->resource[i].start = res->start + size * id;
  98                 virtfn->resource[i].end = virtfn->resource[i].start + size - 1;
  99                 rc = request_resource(res, &virtfn->resource[i]);
 100                 BUG_ON(rc);
 101         }
 102
 103         if (reset)
 104                 __pci_reset_function(virtfn);
 105
 106         pci_device_add(virtfn, virtfn->bus);
 107         mutex_unlock(&iov->dev->sriov->lock);
 108
 109         sprintf(buf, "virtfn%u", id);
 110         rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
 111         if (rc)
 112                 goto failed1;
 113         rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
 114         if (rc)
 115                 goto failed2;
 116
 117         kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
 118
 119         pci_bus_add_device(virtfn);
 120
 121         return 0;
 122
 123 failed2:
 124         sysfs_remove_link(&dev->dev.kobj, buf);
 125 failed1:
 126         pci_dev_put(dev);
 127         mutex_lock(&iov->dev->sriov->lock);
 128         pci_stop_and_remove_bus_device(virtfn);
 129 failed0:
 130         virtfn_remove_bus(dev->bus, bus);
 131 failed:
 132         mutex_unlock(&iov->dev->sriov->lock);
 133
 134         return rc;
 135 }
 136
 137 static void virtfn_remove(struct pci_dev *dev, int id, int reset)
 138 {
 139         char buf[VIRTFN_ID_LEN];
 140         struct pci_dev *virtfn;
 141         struct pci_sriov *iov = dev->sriov;
 142
 143         virtfn = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus),
 144                                              virtfn_bus(dev, id),
 145                                              virtfn_devfn(dev, id));
 146         if (!virtfn)
 147                 return;
 148
 149         if (reset) {
 150                 device_release_driver(&virtfn->dev);
 151                 __pci_reset_function(virtfn);
 152         }
 153
 154         sprintf(buf, "virtfn%u", id);
 155         sysfs_remove_link(&dev->dev.kobj, buf);
 156         /*
 157          * pci_stop_dev() could have been called for this virtfn already,
 158          * so the directory for the virtfn may have been removed before.
 159          * Double check to avoid spurious sysfs warnings.
 160          */
 161         if (virtfn->dev.kobj.sd)
 162                 sysfs_remove_link(&virtfn->dev.kobj, "physfn");
 163
 164         mutex_lock(&iov->dev->sriov->lock);
 165         pci_stop_and_remove_bus_device(virtfn);
 166         virtfn_remove_bus(dev->bus, virtfn->bus);
 167         mutex_unlock(&iov->dev->sriov->lock);
 168
 169         /* balance pci_get_domain_bus_and_slot() */
 170         pci_dev_put(virtfn);
 171         pci_dev_put(dev);
 172 }
 173
 174 static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 175 {
 176         int rc;
 177         int i, j;
 178         int nres;
 179         u16 offset, stride, initial;
 180         struct resource *res;
 181         struct pci_dev *pdev;
 182         struct pci_sriov *iov = dev->sriov;
 183         int bars = 0;
 184
 185         if (!nr_virtfn)
 186                 return 0;
 187
 188         if (iov->num_VFs)
 189                 return -EINVAL;
 190
 191         pci_read_config_word(dev, iov->pos + PCI_SRIOV_INITIAL_VF, &initial);
 192         if (initial > iov->total_VFs ||
 193             (!(iov->cap & PCI_SRIOV_CAP_VFM) && (initial != iov->total_VFs)))
 194                 return -EIO;
 195
 196         if (nr_virtfn < 0 || nr_virtfn > iov->total_VFs ||
 197             (!(iov->cap & PCI_SRIOV_CAP_VFM) && (nr_virtfn > initial)))
 198                 return -EINVAL;
 199
 200         pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_OFFSET, &offset);
 201         pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_STRIDE, &stride);
 202         if (!offset || (nr_virtfn > 1 && !stride))
 203                 return -EIO;
 204
 205         nres = 0;
 206         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 207                 bars |= (1 << (i + PCI_IOV_RESOURCES));
 208                 res = dev->resource + PCI_IOV_RESOURCES + i;
 209                 if (res->parent)
 210                         nres++;
 211         }
 212         if (nres != iov->nres) {
 213                 dev_err(&dev->dev, "not enough MMIO resources for SR-IOV\n");
 214                 return -ENOMEM;
 215         }
 216
 217         iov->offset = offset;
 218         iov->stride = stride;
 219
 220         if (virtfn_bus(dev, nr_virtfn - 1) > dev->bus->busn_res.end) {
 221                 dev_err(&dev->dev, "SR-IOV: bus number out of range\n");
 222                 return -ENOMEM;
 223         }
 224
 225         if (pci_enable_resources(dev, bars)) {
 226                 dev_err(&dev->dev, "SR-IOV: IOV BARS not allocated\n");
 227                 return -ENOMEM;
 228         }
 229
 230         if (iov->link != dev->devfn) {
 231                 pdev = pci_get_slot(dev->bus, iov->link);
 232                 if (!pdev)
 233                         return -ENODEV;
 234
 235                 if (!pdev->is_physfn) {
 236                         pci_dev_put(pdev);
 237                         return -ENOSYS;
 238                 }
 239
 240                 rc = sysfs_create_link(&dev->dev.kobj,
 241                                         &pdev->dev.kobj, "dep_link");
 242                 pci_dev_put(pdev);
 243                 if (rc)
 244                         return rc;
 245         }
 246
 247         pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn);
 248         iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
 249         pci_cfg_access_lock(dev);
 250         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 251         msleep(100);
 252         pci_cfg_access_unlock(dev);
 253
 254         iov->initial_VFs = initial;
 255         if (nr_virtfn < initial)
 256                 initial = nr_virtfn;
 257
 258         for (i = 0; i < initial; i++) {
 259                 rc = virtfn_add(dev, i, 0);
 260                 if (rc)
 261                         goto failed;
 262         }
 263
 264         kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
 265         iov->num_VFs = nr_virtfn;
 266
 267         return 0;
 268
 269 failed:
 270         for (j = 0; j < i; j++)
 271                 virtfn_remove(dev, j, 0);
 272
 273         iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 274         pci_cfg_access_lock(dev);
 275         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 276         pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, 0);
 277         ssleep(1);
 278         pci_cfg_access_unlock(dev);
 279
 280         if (iov->link != dev->devfn)
 281                 sysfs_remove_link(&dev->dev.kobj, "dep_link");
 282
 283         return rc;
 284 }
 285
 286 static void sriov_disable(struct pci_dev *dev)
 287 {
 288         int i;
 289         struct pci_sriov *iov = dev->sriov;
 290
 291         if (!iov->num_VFs)
 292                 return;
 293
 294         for (i = 0; i < iov->num_VFs; i++)
 295                 virtfn_remove(dev, i, 0);
 296
 297         iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 298         pci_cfg_access_lock(dev);
 299         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 300         ssleep(1);
 301         pci_cfg_access_unlock(dev);
 302
 303         if (iov->link != dev->devfn)
 304                 sysfs_remove_link(&dev->dev.kobj, "dep_link");
 305
 306         iov->num_VFs = 0;
 307         pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, 0);
 308 }
 309
 310 static int sriov_init(struct pci_dev *dev, int pos)
 311 {
 312         int i;
 313         int rc;
 314         int nres;
 315         u32 pgsz;
 316         u16 ctrl, total, offset, stride;
 317         struct pci_sriov *iov;
 318         struct resource *res;
 319         struct pci_dev *pdev;
 320
 321         if (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_END &&
 322             pci_pcie_type(dev) != PCI_EXP_TYPE_ENDPOINT)
 323                 return -ENODEV;
 324
 325         pci_read_config_word(dev, pos + PCI_SRIOV_CTRL, &ctrl);
 326         if (ctrl & PCI_SRIOV_CTRL_VFE) {
 327                 pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, 0);
 328                 ssleep(1);
 329         }
 330
 331         pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total);
 332         if (!total)
 333                 return 0;
 334
 335         ctrl = 0;
 336         list_for_each_entry(pdev, &dev->bus->devices, bus_list)
 337                 if (pdev->is_physfn)
 338                         goto found;
 339
 340         pdev = NULL;
 341         if (pci_ari_enabled(dev->bus))
 342                 ctrl |= PCI_SRIOV_CTRL_ARI;
 343
 344 found:
 345         pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
 346         pci_write_config_word(dev, pos + PCI_SRIOV_NUM_VF, 0);
 347         pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset);
 348         pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride);
 349         if (!offset || (total > 1 && !stride))
 350                 return -EIO;
 351
 352         pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
 353         i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
 354         pgsz &= ~((1 << i) - 1);
 355         if (!pgsz)
 356                 return -EIO;
 357
 358         pgsz &= ~(pgsz - 1);
 359         pci_write_config_dword(dev, pos + PCI_SRIOV_SYS_PGSIZE, pgsz);
 360
 361         nres = 0;
 362         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 363                 res = dev->resource + PCI_IOV_RESOURCES + i;
 364                 i += __pci_read_base(dev, pci_bar_unknown, res,
 365                                      pos + PCI_SRIOV_BAR + i * 4);
 366                 if (!res->flags)
 367                         continue;
 368                 if (resource_size(res) & (PAGE_SIZE - 1)) {
 369                         rc = -EIO;
 370                         goto failed;
 371                 }
 372                 res->end = res->start + resource_size(res) * total - 1;
 373                 nres++;
 374         }
 375
 376         iov = kzalloc(sizeof(*iov), GFP_KERNEL);
 377         if (!iov) {
 378                 rc = -ENOMEM;
 379                 goto failed;
 380         }
 381
 382         iov->pos = pos;
 383         iov->nres = nres;
 384         iov->ctrl = ctrl;
 385         iov->total_VFs = total;
 386         iov->offset = offset;
 387         iov->stride = stride;
 388         iov->pgsz = pgsz;
 389         iov->self = dev;
 390         pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
 391         pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
 392         if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
 393                 iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);
 394
 395         if (pdev)
 396                 iov->dev = pci_dev_get(pdev);
 397         else
 398                 iov->dev = dev;
 399
 400         mutex_init(&iov->lock);
 401
 402         dev->sriov = iov;
 403         dev->is_physfn = 1;
 404
 405         return 0;
 406
 407 failed:
 408         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 409                 res = dev->resource + PCI_IOV_RESOURCES + i;
 410                 res->flags = 0;
 411         }
 412
 413         return rc;
 414 }
 415
 416 static void sriov_release(struct pci_dev *dev)
 417 {
 418         BUG_ON(dev->sriov->num_VFs);
 419
 420         if (dev != dev->sriov->dev)
 421                 pci_dev_put(dev->sriov->dev);
 422
 423         mutex_destroy(&dev->sriov->lock);
 424
 425         kfree(dev->sriov);
 426         dev->sriov = NULL;
 427 }
 428
 429 static void sriov_restore_state(struct pci_dev *dev)
 430 {
 431         int i;
 432         u16 ctrl;
 433         struct pci_sriov *iov = dev->sriov;
 434
 435         pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &ctrl);
 436         if (ctrl & PCI_SRIOV_CTRL_VFE)
 437                 return;
 438
 439         for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++)
 440                 pci_update_resource(dev, i);
 441
 442         pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
 443         pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, iov->num_VFs);
 444         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 445         if (iov->ctrl & PCI_SRIOV_CTRL_VFE)
 446                 msleep(100);
 447 }
 448
 449 /**
 450  * pci_iov_init - initialize the IOV capability
 451  * @dev: the PCI device
 452  *
 453  * Returns 0 on success, or negative on failure.
 454  */
 455 int pci_iov_init(struct pci_dev *dev)
 456 {
 457         int pos;
 458
 459         if (!pci_is_pcie(dev))
 460                 return -ENODEV;
 461
 462         pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
 463         if (pos)
 464                 return sriov_init(dev, pos);
 465
 466         return -ENODEV;
 467 }
 468
 469 /**
 470  * pci_iov_release - release resources used by the IOV capability
 471  * @dev: the PCI device
 472  */
 473 void pci_iov_release(struct pci_dev *dev)
 474 {
 475         if (dev->is_physfn)
 476                 sriov_release(dev);
 477 }
 478
 479 /**
 480  * pci_iov_resource_bar - get position of the SR-IOV BAR
 481  * @dev: the PCI device
 482  * @resno: the resource number
 483  * @type: the BAR type to be filled in
 484  *
 485  * Returns position of the BAR encapsulated in the SR-IOV capability.
 486  */
 487 int pci_iov_resource_bar(struct pci_dev *dev, int resno,
 488                          enum pci_bar_type *type)
 489 {
 490         if (resno < PCI_IOV_RESOURCES || resno > PCI_IOV_RESOURCE_END)
 491                 return 0;
 492
 493         BUG_ON(!dev->is_physfn);
 494
 495         *type = pci_bar_unknown;
 496
 497         return dev->sriov->pos + PCI_SRIOV_BAR +
 498                 4 * (resno - PCI_IOV_RESOURCES);
 499 }
 500
 501 /**
 502  * pci_sriov_resource_alignment - get resource alignment for VF BAR
 503  * @dev: the PCI device
 504  * @resno: the resource number
 505  *
 506  * Returns the alignment of the VF BAR found in the SR-IOV capability.
 507  * This is not the same as the resource size which is defined as
 508  * the VF BAR size multiplied by the number of VFs.  The alignment
 509  * is just the VF BAR size.
 510  */
 511 resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
 512 {
 513         struct resource tmp;
 514         enum pci_bar_type type;
 515         int reg = pci_iov_resource_bar(dev, resno, &type);
 516
 517         if (!reg)
 518                 return 0;
 519
 520          __pci_read_base(dev, type, &tmp, reg);
 521         return resource_alignment(&tmp);
 522 }
 523
 524 /**
 525  * pci_restore_iov_state - restore the state of the IOV capability
 526  * @dev: the PCI device
 527  */
 528 void pci_restore_iov_state(struct pci_dev *dev)
 529 {
 530         if (dev->is_physfn)
 531                 sriov_restore_state(dev);
 532 }
 533
 534 /**
 535  * pci_iov_bus_range - find bus range used by Virtual Function
 536  * @bus: the PCI bus
 537  *
 538  * Returns max number of buses (exclude current one) used by Virtual
 539  * Functions.
 540  */
 541 int pci_iov_bus_range(struct pci_bus *bus)
 542 {
 543         int max = 0;
 544         u8 busnr;
 545         struct pci_dev *dev;
 546
 547         list_for_each_entry(dev, &bus->devices, bus_list) {
 548                 if (!dev->is_physfn)
 549                         continue;
 550                 busnr = virtfn_bus(dev, dev->sriov->total_VFs - 1);
 551                 if (busnr > max)
 552                         max = busnr;
 553         }
 554
 555         return max ? max - bus->number : 0;
 556 }
 557
 558 /**
 559  * pci_enable_sriov - enable the SR-IOV capability
 560  * @dev: the PCI device
 561  * @nr_virtfn: number of virtual functions to enable
 562  *
 563  * Returns 0 on success, or negative on failure.
 564  */
 565 int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
 566 {
 567         might_sleep();
 568
 569         if (!dev->is_physfn)
 570                 return -ENOSYS;
 571
 572         return sriov_enable(dev, nr_virtfn);
 573 }
 574 EXPORT_SYMBOL_GPL(pci_enable_sriov);
 575
 576 /**
 577  * pci_disable_sriov - disable the SR-IOV capability
 578  * @dev: the PCI device
 579  */
 580 void pci_disable_sriov(struct pci_dev *dev)
 581 {
 582         might_sleep();
 583
 584         if (!dev->is_physfn)
 585                 return;
 586
 587         sriov_disable(dev);
 588 }
 589 EXPORT_SYMBOL_GPL(pci_disable_sriov);
 590
 591 /**
 592  * pci_num_vf - return number of VFs associated with a PF device_release_driver
 593  * @dev: the PCI device
 594  *
 595  * Returns number of VFs, or 0 if SR-IOV is not enabled.
 596  */
 597 int pci_num_vf(struct pci_dev *dev)
 598 {
 599         if (!dev->is_physfn)
 600                 return 0;
 601
 602         return dev->sriov->num_VFs;
 603 }
 604 EXPORT_SYMBOL_GPL(pci_num_vf);
 605
 606 /**
 607  * pci_vfs_assigned - returns number of VFs are assigned to a guest
 608  * @dev: the PCI device
 609  *
 610  * Returns number of VFs belonging to this device that are assigned to a guest.
 611  * If device is not a physical function returns 0.
 612  */
 613 int pci_vfs_assigned(struct pci_dev *dev)
 614 {
 615         struct pci_dev *vfdev;
 616         unsigned int vfs_assigned = 0;
 617         unsigned short dev_id;
 618
 619         /* only search if we are a PF */
 620         if (!dev->is_physfn)
 621                 return 0;
 622
 623         /*
 624          * determine the device ID for the VFs, the vendor ID will be the
 625          * same as the PF so there is no need to check for that one
 626          */
 627         pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_VF_DID, &dev_id);
 628
 629         /* loop through all the VFs to see if we own any that are assigned */
 630         vfdev = pci_get_device(dev->vendor, dev_id, NULL);
 631         while (vfdev) {
 632                 /*
 633                  * It is considered assigned if it is a virtual function with
 634                  * our dev as the physical function and the assigned bit is set
 635                  */
 636                 if (vfdev->is_virtfn && (vfdev->physfn == dev) &&
 637                         pci_is_dev_assigned(vfdev))
 638                         vfs_assigned++;
 639
 640                 vfdev = pci_get_device(dev->vendor, dev_id, vfdev);
 641         }
 642
 643         return vfs_assigned;
 644 }
 645 EXPORT_SYMBOL_GPL(pci_vfs_assigned);
 646
 647 /**
 648  * pci_sriov_set_totalvfs -- reduce the TotalVFs available
 649  * @dev: the PCI PF device
 650  * @numvfs: number that should be used for TotalVFs supported
 651  *
 652  * Should be called from PF driver's probe routine with
 653  * device's mutex held.
 654  *
 655  * Returns 0 if PF is an SRIOV-capable device and
 656  * value of numvfs valid. If not a PF return -ENOSYS;
 657  * if numvfs is invalid return -EINVAL;
 658  * if VFs already enabled, return -EBUSY.
 659  */
 660 int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
 661 {
 662         if (!dev->is_physfn)
 663                 return -ENOSYS;
 664         if (numvfs > dev->sriov->total_VFs)
 665                 return -EINVAL;
 666
 667         /* Shouldn't change if VFs already enabled */
 668         if (dev->sriov->ctrl & PCI_SRIOV_CTRL_VFE)
 669                 return -EBUSY;
 670         else
 671                 dev->sriov->driver_max_VFs = numvfs;
 672
 673         return 0;
 674 }
 675 EXPORT_SYMBOL_GPL(pci_sriov_set_totalvfs);
 676
 677 /**
 678  * pci_sriov_get_totalvfs -- get total VFs supported on this device
 679  * @dev: the PCI PF device
 680  *
 681  * For a PCIe device with SRIOV support, return the PCIe
 682  * SRIOV capability value of TotalVFs or the value of driver_max_VFs
 683  * if the driver reduced it.  Otherwise 0.
 684  */
 685 int pci_sriov_get_totalvfs(struct pci_dev *dev)
 686 {
 687         if (!dev->is_physfn)
 688                 return 0;
 689
 690         if (dev->sriov->driver_max_VFs)
 691                 return dev->sriov->driver_max_VFs;
 692
 693         return dev->sriov->total_VFs;
 694 }
 695 EXPORT_SYMBOL_GPL(pci_sriov_get_totalvfs);