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