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         int rc;
  37         struct pci_bus *child;
  38
  39         if (bus->number == busnr)
  40                 return bus;
  41
  42         child = pci_find_bus(pci_domain_nr(bus), busnr);
  43         if (child)
  44                 return child;
  45
  46         child = pci_add_new_bus(bus, NULL, busnr);
  47         if (!child)
  48                 return NULL;
  49
  50         child->subordinate = busnr;
  51         child->dev.parent = bus->bridge;
  52         rc = pci_bus_add_child(child);
  53         if (rc) {
  54                 pci_remove_bus(child);
  55                 return NULL;
  56         }
  57
  58         return child;
  59 }
  60
  61 static void virtfn_remove_bus(struct pci_bus *bus, int busnr)
  62 {
  63         struct pci_bus *child;
  64
  65         if (bus->number == busnr)
  66                 return;
  67
  68         child = pci_find_bus(pci_domain_nr(bus), busnr);
  69         BUG_ON(!child);
  70
  71         if (list_empty(&child->devices))
  72                 pci_remove_bus(child);
  73 }
  74
  75 static int virtfn_add(struct pci_dev *dev, int id, int reset)
  76 {
  77         int i;
  78         int rc;
  79         u64 size;
  80         char buf[VIRTFN_ID_LEN];
  81         struct pci_dev *virtfn;
  82         struct resource *res;
  83         struct pci_sriov *iov = dev->sriov;
  84
  85         virtfn = alloc_pci_dev();
  86         if (!virtfn)
  87                 return -ENOMEM;
  88
  89         mutex_lock(&iov->dev->sriov->lock);
  90         virtfn->bus = virtfn_add_bus(dev->bus, virtfn_bus(dev, id));
  91         if (!virtfn->bus) {
  92                 kfree(virtfn);
  93                 mutex_unlock(&iov->dev->sriov->lock);
  94                 return -ENOMEM;
  95         }
  96         virtfn->devfn = virtfn_devfn(dev, id);
  97         virtfn->vendor = dev->vendor;
  98         pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_DID, &virtfn->device);
  99         pci_setup_device(virtfn);
 100         virtfn->dev.parent = dev->dev.parent;
 101
 102         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 103                 res = dev->resource + PCI_IOV_RESOURCES + i;
 104                 if (!res->parent)
 105                         continue;
 106                 virtfn->resource[i].name = pci_name(virtfn);
 107                 virtfn->resource[i].flags = res->flags;
 108                 size = resource_size(res);
 109                 do_div(size, iov->total);
 110                 virtfn->resource[i].start = res->start + size * id;
 111                 virtfn->resource[i].end = virtfn->resource[i].start + size - 1;
 112                 rc = request_resource(res, &virtfn->resource[i]);
 113                 BUG_ON(rc);
 114         }
 115
 116         if (reset)
 117                 __pci_reset_function(virtfn);
 118
 119         pci_device_add(virtfn, virtfn->bus);
 120         mutex_unlock(&iov->dev->sriov->lock);
 121
 122         virtfn->physfn = pci_dev_get(dev);
 123         virtfn->is_virtfn = 1;
 124
 125         rc = pci_bus_add_device(virtfn);
 126         if (rc)
 127                 goto failed1;
 128         sprintf(buf, "virtfn%u", id);
 129         rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
 130         if (rc)
 131                 goto failed1;
 132         rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
 133         if (rc)
 134                 goto failed2;
 135
 136         kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
 137
 138         return 0;
 139
 140 failed2:
 141         sysfs_remove_link(&dev->dev.kobj, buf);
 142 failed1:
 143         pci_dev_put(dev);
 144         mutex_lock(&iov->dev->sriov->lock);
 145         pci_remove_bus_device(virtfn);
 146         virtfn_remove_bus(dev->bus, virtfn_bus(dev, id));
 147         mutex_unlock(&iov->dev->sriov->lock);
 148
 149         return rc;
 150 }
 151
 152 static void virtfn_remove(struct pci_dev *dev, int id, int reset)
 153 {
 154         char buf[VIRTFN_ID_LEN];
 155         struct pci_bus *bus;
 156         struct pci_dev *virtfn;
 157         struct pci_sriov *iov = dev->sriov;
 158
 159         bus = pci_find_bus(pci_domain_nr(dev->bus), virtfn_bus(dev, id));
 160         if (!bus)
 161                 return;
 162
 163         virtfn = pci_get_slot(bus, virtfn_devfn(dev, id));
 164         if (!virtfn)
 165                 return;
 166
 167         pci_dev_put(virtfn);
 168
 169         if (reset) {
 170                 device_release_driver(&virtfn->dev);
 171                 __pci_reset_function(virtfn);
 172         }
 173
 174         sprintf(buf, "virtfn%u", id);
 175         sysfs_remove_link(&dev->dev.kobj, buf);
 176         sysfs_remove_link(&virtfn->dev.kobj, "physfn");
 177
 178         mutex_lock(&iov->dev->sriov->lock);
 179         pci_remove_bus_device(virtfn);
 180         virtfn_remove_bus(dev->bus, virtfn_bus(dev, id));
 181         mutex_unlock(&iov->dev->sriov->lock);
 182
 183         pci_dev_put(dev);
 184 }
 185
 186 static int sriov_migration(struct pci_dev *dev)
 187 {
 188         u16 status;
 189         struct pci_sriov *iov = dev->sriov;
 190
 191         if (!iov->nr_virtfn)
 192                 return 0;
 193
 194         if (!(iov->cap & PCI_SRIOV_CAP_VFM))
 195                 return 0;
 196
 197         pci_read_config_word(dev, iov->pos + PCI_SRIOV_STATUS, &status);
 198         if (!(status & PCI_SRIOV_STATUS_VFM))
 199                 return 0;
 200
 201         schedule_work(&iov->mtask);
 202
 203         return 1;
 204 }
 205
 206 static void sriov_migration_task(struct work_struct *work)
 207 {
 208         int i;
 209         u8 state;
 210         u16 status;
 211         struct pci_sriov *iov = container_of(work, struct pci_sriov, mtask);
 212
 213         for (i = iov->initial; i < iov->nr_virtfn; i++) {
 214                 state = readb(iov->mstate + i);
 215                 if (state == PCI_SRIOV_VFM_MI) {
 216                         writeb(PCI_SRIOV_VFM_AV, iov->mstate + i);
 217                         state = readb(iov->mstate + i);
 218                         if (state == PCI_SRIOV_VFM_AV)
 219                                 virtfn_add(iov->self, i, 1);
 220                 } else if (state == PCI_SRIOV_VFM_MO) {
 221                         virtfn_remove(iov->self, i, 1);
 222                         writeb(PCI_SRIOV_VFM_UA, iov->mstate + i);
 223                         state = readb(iov->mstate + i);
 224                         if (state == PCI_SRIOV_VFM_AV)
 225                                 virtfn_add(iov->self, i, 0);
 226                 }
 227         }
 228
 229         pci_read_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, &status);
 230         status &= ~PCI_SRIOV_STATUS_VFM;
 231         pci_write_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, status);
 232 }
 233
 234 static int sriov_enable_migration(struct pci_dev *dev, int nr_virtfn)
 235 {
 236         int bir;
 237         u32 table;
 238         resource_size_t pa;
 239         struct pci_sriov *iov = dev->sriov;
 240
 241         if (nr_virtfn <= iov->initial)
 242                 return 0;
 243
 244         pci_read_config_dword(dev, iov->pos + PCI_SRIOV_VFM, &table);
 245         bir = PCI_SRIOV_VFM_BIR(table);
 246         if (bir > PCI_STD_RESOURCE_END)
 247                 return -EIO;
 248
 249         table = PCI_SRIOV_VFM_OFFSET(table);
 250         if (table + nr_virtfn > pci_resource_len(dev, bir))
 251                 return -EIO;
 252
 253         pa = pci_resource_start(dev, bir) + table;
 254         iov->mstate = ioremap(pa, nr_virtfn);
 255         if (!iov->mstate)
 256                 return -ENOMEM;
 257
 258         INIT_WORK(&iov->mtask, sriov_migration_task);
 259
 260         iov->ctrl |= PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR;
 261         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 262
 263         return 0;
 264 }
 265
 266 static void sriov_disable_migration(struct pci_dev *dev)
 267 {
 268         struct pci_sriov *iov = dev->sriov;
 269
 270         iov->ctrl &= ~(PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR);
 271         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 272
 273         cancel_work_sync(&iov->mtask);
 274         iounmap(iov->mstate);
 275 }
 276
 277 static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 278 {
 279         int rc;
 280         int i, j;
 281         int nres;
 282         u16 offset, stride, initial;
 283         struct resource *res;
 284         struct pci_dev *pdev;
 285         struct pci_sriov *iov = dev->sriov;
 286         int bars = 0;
 287
 288         if (!nr_virtfn)
 289                 return 0;
 290
 291         if (iov->nr_virtfn)
 292                 return -EINVAL;
 293
 294         pci_read_config_word(dev, iov->pos + PCI_SRIOV_INITIAL_VF, &initial);
 295         if (initial > iov->total ||
 296             (!(iov->cap & PCI_SRIOV_CAP_VFM) && (initial != iov->total)))
 297                 return -EIO;
 298
 299         if (nr_virtfn < 0 || nr_virtfn > iov->total ||
 300             (!(iov->cap & PCI_SRIOV_CAP_VFM) && (nr_virtfn > initial)))
 301                 return -EINVAL;
 302
 303         pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn);
 304         pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_OFFSET, &offset);
 305         pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_STRIDE, &stride);
 306         if (!offset || (nr_virtfn > 1 && !stride))
 307                 return -EIO;
 308
 309         nres = 0;
 310         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 311                 bars |= (1 << (i + PCI_IOV_RESOURCES));
 312                 res = dev->resource + PCI_IOV_RESOURCES + i;
 313                 if (res->parent)
 314                         nres++;
 315         }
 316         if (nres != iov->nres) {
 317                 dev_err(&dev->dev, "not enough MMIO resources for SR-IOV\n");
 318                 return -ENOMEM;
 319         }
 320
 321         iov->offset = offset;
 322         iov->stride = stride;
 323
 324         if (virtfn_bus(dev, nr_virtfn - 1) > dev->bus->subordinate) {
 325                 dev_err(&dev->dev, "SR-IOV: bus number out of range\n");
 326                 return -ENOMEM;
 327         }
 328
 329         if (pci_enable_resources(dev, bars)) {
 330                 dev_err(&dev->dev, "SR-IOV: IOV BARS not allocated\n");
 331                 return -ENOMEM;
 332         }
 333
 334         if (iov->link != dev->devfn) {
 335                 pdev = pci_get_slot(dev->bus, iov->link);
 336                 if (!pdev)
 337                         return -ENODEV;
 338
 339                 pci_dev_put(pdev);
 340
 341                 if (!pdev->is_physfn)
 342                         return -ENODEV;
 343
 344                 rc = sysfs_create_link(&dev->dev.kobj,
 345                                         &pdev->dev.kobj, "dep_link");
 346                 if (rc)
 347                         return rc;
 348         }
 349
 350         pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
 351
 352         iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
 353         pci_cfg_access_lock(dev);
 354         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 355         msleep(100);
 356         pci_cfg_access_unlock(dev);
 357
 358         iov->initial = initial;
 359         if (nr_virtfn < initial)
 360                 initial = nr_virtfn;
 361
 362         for (i = 0; i < initial; i++) {
 363                 rc = virtfn_add(dev, i, 0);
 364                 if (rc)
 365                         goto failed;
 366         }
 367
 368         if (iov->cap & PCI_SRIOV_CAP_VFM) {
 369                 rc = sriov_enable_migration(dev, nr_virtfn);
 370                 if (rc)
 371                         goto failed;
 372         }
 373
 374         kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
 375         iov->nr_virtfn = nr_virtfn;
 376
 377         return 0;
 378
 379 failed:
 380         for (j = 0; j < i; j++)
 381                 virtfn_remove(dev, j, 0);
 382
 383         iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 384         pci_cfg_access_lock(dev);
 385         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 386         ssleep(1);
 387         pci_cfg_access_unlock(dev);
 388
 389         if (iov->link != dev->devfn)
 390                 sysfs_remove_link(&dev->dev.kobj, "dep_link");
 391
 392         return rc;
 393 }
 394
 395 static void sriov_disable(struct pci_dev *dev)
 396 {
 397         int i;
 398         struct pci_sriov *iov = dev->sriov;
 399
 400         if (!iov->nr_virtfn)
 401                 return;
 402
 403         if (iov->cap & PCI_SRIOV_CAP_VFM)
 404                 sriov_disable_migration(dev);
 405
 406         for (i = 0; i < iov->nr_virtfn; i++)
 407                 virtfn_remove(dev, i, 0);
 408
 409         iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 410         pci_cfg_access_lock(dev);
 411         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 412         ssleep(1);
 413         pci_cfg_access_unlock(dev);
 414
 415         if (iov->link != dev->devfn)
 416                 sysfs_remove_link(&dev->dev.kobj, "dep_link");
 417
 418         iov->nr_virtfn = 0;
 419 }
 420
 421 static int sriov_init(struct pci_dev *dev, int pos)
 422 {
 423         int i;
 424         int rc;
 425         int nres;
 426         u32 pgsz;
 427         u16 ctrl, total, offset, stride;
 428         struct pci_sriov *iov;
 429         struct resource *res;
 430         struct pci_dev *pdev;
 431
 432         if (dev->pcie_type != PCI_EXP_TYPE_RC_END &&
 433             dev->pcie_type != PCI_EXP_TYPE_ENDPOINT)
 434                 return -ENODEV;
 435
 436         pci_read_config_word(dev, pos + PCI_SRIOV_CTRL, &ctrl);
 437         if (ctrl & PCI_SRIOV_CTRL_VFE) {
 438                 pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, 0);
 439                 ssleep(1);
 440         }
 441
 442         pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total);
 443         if (!total)
 444                 return 0;
 445
 446         ctrl = 0;
 447         list_for_each_entry(pdev, &dev->bus->devices, bus_list)
 448                 if (pdev->is_physfn)
 449                         goto found;
 450
 451         pdev = NULL;
 452         if (pci_ari_enabled(dev->bus))
 453                 ctrl |= PCI_SRIOV_CTRL_ARI;
 454
 455 found:
 456         pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
 457         pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset);
 458         pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride);
 459         if (!offset || (total > 1 && !stride))
 460                 return -EIO;
 461
 462         pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
 463         i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
 464         pgsz &= ~((1 << i) - 1);
 465         if (!pgsz)
 466                 return -EIO;
 467
 468         pgsz &= ~(pgsz - 1);
 469
 470         nres = 0;
 471         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 472                 res = dev->resource + PCI_IOV_RESOURCES + i;
 473                 i += __pci_read_base(dev, pci_bar_unknown, res,
 474                                      pos + PCI_SRIOV_BAR + i * 4);
 475                 if (!res->flags)
 476                         continue;
 477                 if (resource_size(res) & (PAGE_SIZE - 1)) {
 478                         rc = -EIO;
 479                         goto failed;
 480                 }
 481                 res->end = res->start + resource_size(res) * total - 1;
 482                 nres++;
 483         }
 484
 485         iov = kzalloc(sizeof(*iov), GFP_KERNEL);
 486         if (!iov) {
 487                 rc = -ENOMEM;
 488                 goto failed;
 489         }
 490
 491         iov->pos = pos;
 492         iov->nres = nres;
 493         iov->ctrl = ctrl;
 494         iov->total = total;
 495         iov->offset = offset;
 496         iov->stride = stride;
 497         iov->pgsz = pgsz;
 498         iov->self = dev;
 499         pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
 500         pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
 501         if (dev->pcie_type == PCI_EXP_TYPE_RC_END)
 502                 iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);
 503
 504         if (pdev)
 505                 iov->dev = pci_dev_get(pdev);
 506         else
 507                 iov->dev = dev;
 508
 509         mutex_init(&iov->lock);
 510
 511         dev->sriov = iov;
 512         dev->is_physfn = 1;
 513
 514         return 0;
 515
 516 failed:
 517         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 518                 res = dev->resource + PCI_IOV_RESOURCES + i;
 519                 res->flags = 0;
 520         }
 521
 522         return rc;
 523 }
 524
 525 static void sriov_release(struct pci_dev *dev)
 526 {
 527         BUG_ON(dev->sriov->nr_virtfn);
 528
 529         if (dev != dev->sriov->dev)
 530                 pci_dev_put(dev->sriov->dev);
 531
 532         mutex_destroy(&dev->sriov->lock);
 533
 534         kfree(dev->sriov);
 535         dev->sriov = NULL;
 536 }
 537
 538 static void sriov_restore_state(struct pci_dev *dev)
 539 {
 540         int i;
 541         u16 ctrl;
 542         struct pci_sriov *iov = dev->sriov;
 543
 544         pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &ctrl);
 545         if (ctrl & PCI_SRIOV_CTRL_VFE)
 546                 return;
 547
 548         for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++)
 549                 pci_update_resource(dev, i);
 550
 551         pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
 552         pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, iov->nr_virtfn);
 553         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 554         if (iov->ctrl & PCI_SRIOV_CTRL_VFE)
 555                 msleep(100);
 556 }
 557
 558 /**
 559  * pci_iov_init - initialize the IOV capability
 560  * @dev: the PCI device
 561  *
 562  * Returns 0 on success, or negative on failure.
 563  */
 564 int pci_iov_init(struct pci_dev *dev)
 565 {
 566         int pos;
 567
 568         if (!pci_is_pcie(dev))
 569                 return -ENODEV;
 570
 571         pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
 572         if (pos)
 573                 return sriov_init(dev, pos);
 574
 575         return -ENODEV;
 576 }
 577
 578 /**
 579  * pci_iov_release - release resources used by the IOV capability
 580  * @dev: the PCI device
 581  */
 582 void pci_iov_release(struct pci_dev *dev)
 583 {
 584         if (dev->is_physfn)
 585                 sriov_release(dev);
 586 }
 587
 588 /**
 589  * pci_iov_resource_bar - get position of the SR-IOV BAR
 590  * @dev: the PCI device
 591  * @resno: the resource number
 592  * @type: the BAR type to be filled in
 593  *
 594  * Returns position of the BAR encapsulated in the SR-IOV capability.
 595  */
 596 int pci_iov_resource_bar(struct pci_dev *dev, int resno,
 597                          enum pci_bar_type *type)
 598 {
 599         if (resno < PCI_IOV_RESOURCES || resno > PCI_IOV_RESOURCE_END)
 600                 return 0;
 601
 602         BUG_ON(!dev->is_physfn);
 603
 604         *type = pci_bar_unknown;
 605
 606         return dev->sriov->pos + PCI_SRIOV_BAR +
 607                 4 * (resno - PCI_IOV_RESOURCES);
 608 }
 609
 610 /**
 611  * pci_sriov_resource_alignment - get resource alignment for VF BAR
 612  * @dev: the PCI device
 613  * @resno: the resource number
 614  *
 615  * Returns the alignment of the VF BAR found in the SR-IOV capability.
 616  * This is not the same as the resource size which is defined as
 617  * the VF BAR size multiplied by the number of VFs.  The alignment
 618  * is just the VF BAR size.
 619  */
 620 resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
 621 {
 622         struct resource tmp;
 623         enum pci_bar_type type;
 624         int reg = pci_iov_resource_bar(dev, resno, &type);
 625
 626         if (!reg)
 627                 return 0;
 628
 629          __pci_read_base(dev, type, &tmp, reg);
 630         return resource_alignment(&tmp);
 631 }
 632
 633 /**
 634  * pci_restore_iov_state - restore the state of the IOV capability
 635  * @dev: the PCI device
 636  */
 637 void pci_restore_iov_state(struct pci_dev *dev)
 638 {
 639         if (dev->is_physfn)
 640                 sriov_restore_state(dev);
 641 }
 642
 643 /**
 644  * pci_iov_bus_range - find bus range used by Virtual Function
 645  * @bus: the PCI bus
 646  *
 647  * Returns max number of buses (exclude current one) used by Virtual
 648  * Functions.
 649  */
 650 int pci_iov_bus_range(struct pci_bus *bus)
 651 {
 652         int max = 0;
 653         u8 busnr;
 654         struct pci_dev *dev;
 655
 656         list_for_each_entry(dev, &bus->devices, bus_list) {
 657                 if (!dev->is_physfn)
 658                         continue;
 659                 busnr = virtfn_bus(dev, dev->sriov->total - 1);
 660                 if (busnr > max)
 661                         max = busnr;
 662         }
 663
 664         return max ? max - bus->number : 0;
 665 }
 666
 667 /**
 668  * pci_enable_sriov - enable the SR-IOV capability
 669  * @dev: the PCI device
 670  * @nr_virtfn: number of virtual functions to enable
 671  *
 672  * Returns 0 on success, or negative on failure.
 673  */
 674 int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
 675 {
 676         might_sleep();
 677
 678         if (!dev->is_physfn)
 679                 return -ENODEV;
 680
 681         return sriov_enable(dev, nr_virtfn);
 682 }
 683 EXPORT_SYMBOL_GPL(pci_enable_sriov);
 684
 685 /**
 686  * pci_disable_sriov - disable the SR-IOV capability
 687  * @dev: the PCI device
 688  */
 689 void pci_disable_sriov(struct pci_dev *dev)
 690 {
 691         might_sleep();
 692
 693         if (!dev->is_physfn)
 694                 return;
 695
 696         sriov_disable(dev);
 697 }
 698 EXPORT_SYMBOL_GPL(pci_disable_sriov);
 699
 700 /**
 701  * pci_sriov_migration - notify SR-IOV core of Virtual Function Migration
 702  * @dev: the PCI device
 703  *
 704  * Returns IRQ_HANDLED if the IRQ is handled, or IRQ_NONE if not.
 705  *
 706  * Physical Function driver is responsible to register IRQ handler using
 707  * VF Migration Interrupt Message Number, and call this function when the
 708  * interrupt is generated by the hardware.
 709  */
 710 irqreturn_t pci_sriov_migration(struct pci_dev *dev)
 711 {
 712         if (!dev->is_physfn)
 713                 return IRQ_NONE;
 714
 715         return sriov_migration(dev) ? IRQ_HANDLED : IRQ_NONE;
 716 }
 717 EXPORT_SYMBOL_GPL(pci_sriov_migration);
 718
 719 /**
 720  * pci_num_vf - return number of VFs associated with a PF device_release_driver
 721  * @dev: the PCI device
 722  *
 723  * Returns number of VFs, or 0 if SR-IOV is not enabled.
 724  */
 725 int pci_num_vf(struct pci_dev *dev)
 726 {
 727         if (!dev || !dev->is_physfn)
 728                 return 0;
 729         else
 730                 return dev->sriov->nr_virtfn;
 731 }
 732 EXPORT_SYMBOL_GPL(pci_num_vf);