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