drivers/pci/iov.c

   1 /*
   2  * drivers/pci/iov.c
   3  *
   4  * Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
   5  *
   6  * PCI Express I/O Virtualization (IOV) support.
   7  *   Single Root IOV 1.0
   8  *   Address Translation Service 1.0
   9  */
  10
  11 #include <linux/pci.h>
  12 #include <linux/slab.h>
  13 #include <linux/mutex.h>
  14 #include <linux/export.h>
  15 #include <linux/string.h>
  16 #include <linux/delay.h>
  17 #include <linux/pci-ats.h>
  18 #include "pci.h"
  19
  20 #define VIRTFN_ID_LEN   16
  21
  22 int pci_iov_virtfn_bus(struct pci_dev *dev, int vf_id)
  23 {
  24         if (!dev->is_physfn)
  25                 return -EINVAL;
  26         return dev->bus->number + ((dev->devfn + dev->sriov->offset +
  27                                     dev->sriov->stride * vf_id) >> 8);
  28 }
  29
  30 int pci_iov_virtfn_devfn(struct pci_dev *dev, int vf_id)
  31 {
  32         if (!dev->is_physfn)
  33                 return -EINVAL;
  34         return (dev->devfn + dev->sriov->offset +
  35                 dev->sriov->stride * vf_id) & 0xff;
  36 }
  37
  38 /*
  39  * Per SR-IOV spec sec 3.3.10 and 3.3.11, First VF Offset and VF Stride may
  40  * change when NumVFs changes.
  41  *
  42  * Update iov->offset and iov->stride when NumVFs is written.
  43  */
  44 static inline void pci_iov_set_numvfs(struct pci_dev *dev, int nr_virtfn)
  45 {
  46         struct pci_sriov *iov = dev->sriov;
  47
  48         pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn);
  49         pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_OFFSET, &iov->offset);
  50         pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_STRIDE, &iov->stride);
  51 }
  52
  53 /*
  54  * The PF consumes one bus number.  NumVFs, First VF Offset, and VF Stride
  55  * determine how many additional bus numbers will be consumed by VFs.
  56  *
  57  * Iterate over all valid NumVFs, validate offset and stride, and calculate
  58  * the maximum number of bus numbers that could ever be required.
  59  */
  60 static int compute_max_vf_buses(struct pci_dev *dev)
  61 {
  62         struct pci_sriov *iov = dev->sriov;
  63         int nr_virtfn, busnr, rc = 0;
  64
  65         for (nr_virtfn = iov->total_VFs; nr_virtfn; nr_virtfn--) {
  66                 pci_iov_set_numvfs(dev, nr_virtfn);
  67                 if (!iov->offset || (nr_virtfn > 1 && !iov->stride)) {
  68                         rc = -EIO;
  69                         goto out;
  70                 }
  71
  72                 busnr = pci_iov_virtfn_bus(dev, nr_virtfn - 1);
  73                 if (busnr > iov->max_VF_buses)
  74                         iov->max_VF_buses = busnr;
  75         }
  76
  77 out:
  78         pci_iov_set_numvfs(dev, 0);
  79         return rc;
  80 }
  81
  82 static struct pci_bus *virtfn_add_bus(struct pci_bus *bus, int busnr)
  83 {
  84         struct pci_bus *child;
  85
  86         if (bus->number == busnr)
  87                 return bus;
  88
  89         child = pci_find_bus(pci_domain_nr(bus), busnr);
  90         if (child)
  91                 return child;
  92
  93         child = pci_add_new_bus(bus, NULL, busnr);
  94         if (!child)
  95                 return NULL;
  96
  97         pci_bus_insert_busn_res(child, busnr, busnr);
  98
  99         return child;
 100 }
 101
 102 static void virtfn_remove_bus(struct pci_bus *physbus, struct pci_bus *virtbus)
 103 {
 104         if (physbus != virtbus && list_empty(&virtbus->devices))
 105                 pci_remove_bus(virtbus);
 106 }
 107
 108 resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno)
 109 {
 110         if (!dev->is_physfn)
 111                 return 0;
 112
 113         return dev->sriov->barsz[resno - PCI_IOV_RESOURCES];
 114 }
 115
 116 int pci_iov_add_virtfn(struct pci_dev *dev, int id, int reset)
 117 {
 118         int i;
 119         int rc = -ENOMEM;
 120         u64 size;
 121         char buf[VIRTFN_ID_LEN];
 122         struct pci_dev *virtfn;
 123         struct resource *res;
 124         struct pci_sriov *iov = dev->sriov;
 125         struct pci_bus *bus;
 126
 127         bus = virtfn_add_bus(dev->bus, pci_iov_virtfn_bus(dev, id));
 128         if (!bus)
 129                 goto failed;
 130
 131         virtfn = pci_alloc_dev(bus);
 132         if (!virtfn)
 133                 goto failed0;
 134
 135         virtfn->devfn = pci_iov_virtfn_devfn(dev, id);
 136         virtfn->vendor = dev->vendor;
 137         pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_DID, &virtfn->device);
 138         rc = pci_setup_device(virtfn);
 139         if (rc)
 140                 goto failed0;
 141
 142         virtfn->dev.parent = dev->dev.parent;
 143         virtfn->physfn = pci_dev_get(dev);
 144         virtfn->is_virtfn = 1;
 145         virtfn->multifunction = 0;
 146
 147         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 148                 res = &dev->resource[i + PCI_IOV_RESOURCES];
 149                 if (!res->parent)
 150                         continue;
 151                 virtfn->resource[i].name = pci_name(virtfn);
 152                 virtfn->resource[i].flags = res->flags;
 153                 size = pci_iov_resource_size(dev, i + PCI_IOV_RESOURCES);
 154                 virtfn->resource[i].start = res->start + size * id;
 155                 virtfn->resource[i].end = virtfn->resource[i].start + size - 1;
 156                 rc = request_resource(res, &virtfn->resource[i]);
 157                 BUG_ON(rc);
 158         }
 159
 160         if (reset)
 161                 __pci_reset_function(virtfn);
 162
 163         pci_device_add(virtfn, virtfn->bus);
 164
 165         pci_bus_add_device(virtfn);
 166         sprintf(buf, "virtfn%u", id);
 167         rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
 168         if (rc)
 169                 goto failed1;
 170         rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
 171         if (rc)
 172                 goto failed2;
 173
 174         kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
 175
 176         return 0;
 177
 178 failed2:
 179         sysfs_remove_link(&dev->dev.kobj, buf);
 180 failed1:
 181         pci_dev_put(dev);
 182         pci_stop_and_remove_bus_device(virtfn);
 183 failed0:
 184         virtfn_remove_bus(dev->bus, bus);
 185 failed:
 186
 187         return rc;
 188 }
 189
 190 void pci_iov_remove_virtfn(struct pci_dev *dev, int id, int reset)
 191 {
 192         char buf[VIRTFN_ID_LEN];
 193         struct pci_dev *virtfn;
 194
 195         virtfn = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus),
 196                                              pci_iov_virtfn_bus(dev, id),
 197                                              pci_iov_virtfn_devfn(dev, id));
 198         if (!virtfn)
 199                 return;
 200
 201         if (reset) {
 202                 device_release_driver(&virtfn->dev);
 203                 __pci_reset_function(virtfn);
 204         }
 205
 206         sprintf(buf, "virtfn%u", id);
 207         sysfs_remove_link(&dev->dev.kobj, buf);
 208         /*
 209          * pci_stop_dev() could have been called for this virtfn already,
 210          * so the directory for the virtfn may have been removed before.
 211          * Double check to avoid spurious sysfs warnings.
 212          */
 213         if (virtfn->dev.kobj.sd)
 214                 sysfs_remove_link(&virtfn->dev.kobj, "physfn");
 215
 216         pci_stop_and_remove_bus_device(virtfn);
 217         virtfn_remove_bus(dev->bus, virtfn->bus);
 218
 219         /* balance pci_get_domain_bus_and_slot() */
 220         pci_dev_put(virtfn);
 221         pci_dev_put(dev);
 222 }
 223
 224 int __weak pcibios_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
 225 {
 226         return 0;
 227 }
 228
 229 int __weak pcibios_sriov_disable(struct pci_dev *pdev)
 230 {
 231         return 0;
 232 }
 233
 234 static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 235 {
 236         int rc;
 237         int i;
 238         int nres;
 239         u16 initial;
 240         struct resource *res;
 241         struct pci_dev *pdev;
 242         struct pci_sriov *iov = dev->sriov;
 243         int bars = 0;
 244         int bus;
 245
 246         if (!nr_virtfn)
 247                 return 0;
 248
 249         if (iov->num_VFs)
 250                 return -EINVAL;
 251
 252         pci_read_config_word(dev, iov->pos + PCI_SRIOV_INITIAL_VF, &initial);
 253         if (initial > iov->total_VFs ||
 254             (!(iov->cap & PCI_SRIOV_CAP_VFM) && (initial != iov->total_VFs)))
 255                 return -EIO;
 256
 257         if (nr_virtfn < 0 || nr_virtfn > iov->total_VFs ||
 258             (!(iov->cap & PCI_SRIOV_CAP_VFM) && (nr_virtfn > initial)))
 259                 return -EINVAL;
 260
 261         nres = 0;
 262         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 263                 bars |= (1 << (i + PCI_IOV_RESOURCES));
 264                 res = &dev->resource[i + PCI_IOV_RESOURCES];
 265                 if (res->parent)
 266                         nres++;
 267         }
 268         if (nres != iov->nres) {
 269                 dev_err(&dev->dev, "not enough MMIO resources for SR-IOV\n");
 270                 return -ENOMEM;
 271         }
 272
 273         bus = pci_iov_virtfn_bus(dev, nr_virtfn - 1);
 274         if (bus > dev->bus->busn_res.end) {
 275                 dev_err(&dev->dev, "can't enable %d VFs (bus %02x out of range of %pR)\n",
 276                         nr_virtfn, bus, &dev->bus->busn_res);
 277                 return -ENOMEM;
 278         }
 279
 280         if (pci_enable_resources(dev, bars)) {
 281                 dev_err(&dev->dev, "SR-IOV: IOV BARS not allocated\n");
 282                 return -ENOMEM;
 283         }
 284
 285         if (iov->link != dev->devfn) {
 286                 pdev = pci_get_slot(dev->bus, iov->link);
 287                 if (!pdev)
 288                         return -ENODEV;
 289
 290                 if (!pdev->is_physfn) {
 291                         pci_dev_put(pdev);
 292                         return -ENOSYS;
 293                 }
 294
 295                 rc = sysfs_create_link(&dev->dev.kobj,
 296                                         &pdev->dev.kobj, "dep_link");
 297                 pci_dev_put(pdev);
 298                 if (rc)
 299                         return rc;
 300         }
 301
 302         iov->initial_VFs = initial;
 303         if (nr_virtfn < initial)
 304                 initial = nr_virtfn;
 305
 306         rc = pcibios_sriov_enable(dev, initial);
 307         if (rc) {
 308                 dev_err(&dev->dev, "failure %d from pcibios_sriov_enable()\n", rc);
 309                 goto err_pcibios;
 310         }
 311
 312         pci_iov_set_numvfs(dev, nr_virtfn);
 313         iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
 314         pci_cfg_access_lock(dev);
 315         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 316         msleep(100);
 317         pci_cfg_access_unlock(dev);
 318
 319         for (i = 0; i < initial; i++) {
 320                 rc = pci_iov_add_virtfn(dev, i, 0);
 321                 if (rc)
 322                         goto failed;
 323         }
 324
 325         kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
 326         iov->num_VFs = nr_virtfn;
 327
 328         return 0;
 329
 330 failed:
 331         while (i--)
 332                 pci_iov_remove_virtfn(dev, i, 0);
 333
 334         pcibios_sriov_disable(dev);
 335 err_pcibios:
 336         iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 337         pci_cfg_access_lock(dev);
 338         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 339         ssleep(1);
 340         pci_cfg_access_unlock(dev);
 341
 342         if (iov->link != dev->devfn)
 343                 sysfs_remove_link(&dev->dev.kobj, "dep_link");
 344
 345         pci_iov_set_numvfs(dev, 0);
 346         return rc;
 347 }
 348
 349 static void sriov_disable(struct pci_dev *dev)
 350 {
 351         int i;
 352         struct pci_sriov *iov = dev->sriov;
 353
 354         if (!iov->num_VFs)
 355                 return;
 356
 357         for (i = 0; i < iov->num_VFs; i++)
 358                 pci_iov_remove_virtfn(dev, i, 0);
 359
 360         pcibios_sriov_disable(dev);
 361
 362         iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 363         pci_cfg_access_lock(dev);
 364         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 365         ssleep(1);
 366         pci_cfg_access_unlock(dev);
 367
 368         if (iov->link != dev->devfn)
 369                 sysfs_remove_link(&dev->dev.kobj, "dep_link");
 370
 371         iov->num_VFs = 0;
 372         pci_iov_set_numvfs(dev, 0);
 373 }
 374
 375 static int sriov_init(struct pci_dev *dev, int pos)
 376 {
 377         int i, bar64;
 378         int rc;
 379         int nres;
 380         u32 pgsz;
 381         u16 ctrl, total;
 382         struct pci_sriov *iov;
 383         struct resource *res;
 384         struct pci_dev *pdev;
 385
 386         pci_read_config_word(dev, pos + PCI_SRIOV_CTRL, &ctrl);
 387         if (ctrl & PCI_SRIOV_CTRL_VFE) {
 388                 pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, 0);
 389                 ssleep(1);
 390         }
 391
 392         ctrl = 0;
 393         list_for_each_entry(pdev, &dev->bus->devices, bus_list)
 394                 if (pdev->is_physfn)
 395                         goto found;
 396
 397         pdev = NULL;
 398         if (pci_ari_enabled(dev->bus))
 399                 ctrl |= PCI_SRIOV_CTRL_ARI;
 400
 401 found:
 402         pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
 403
 404         pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total);
 405         if (!total)
 406                 return 0;
 407
 408         pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
 409         i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
 410         pgsz &= ~((1 << i) - 1);
 411         if (!pgsz)
 412                 return -EIO;
 413
 414         pgsz &= ~(pgsz - 1);
 415         pci_write_config_dword(dev, pos + PCI_SRIOV_SYS_PGSIZE, pgsz);
 416
 417         iov = kzalloc(sizeof(*iov), GFP_KERNEL);
 418         if (!iov)
 419                 return -ENOMEM;
 420
 421         nres = 0;
 422         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 423                 res = &dev->resource[i + PCI_IOV_RESOURCES];
 424                 /*
 425                  * If it is already FIXED, don't change it, something
 426                  * (perhaps EA or header fixups) wants it this way.
 427                  */
 428                 if (res->flags & IORESOURCE_PCI_FIXED)
 429                         bar64 = (res->flags & IORESOURCE_MEM_64) ? 1 : 0;
 430                 else
 431                         bar64 = __pci_read_base(dev, pci_bar_unknown, res,
 432                                                 pos + PCI_SRIOV_BAR + i * 4);
 433                 if (!res->flags)
 434                         continue;
 435                 if (resource_size(res) & (PAGE_SIZE - 1)) {
 436                         rc = -EIO;
 437                         goto failed;
 438                 }
 439                 iov->barsz[i] = resource_size(res);
 440                 res->end = res->start + resource_size(res) * total - 1;
 441                 dev_info(&dev->dev, "VF(n) BAR%d space: %pR (contains BAR%d for %d VFs)\n",
 442                          i, res, i, total);
 443                 i += bar64;
 444                 nres++;
 445         }
 446
 447         iov->pos = pos;
 448         iov->nres = nres;
 449         iov->ctrl = ctrl;
 450         iov->total_VFs = total;
 451         iov->pgsz = pgsz;
 452         iov->self = dev;
 453         pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
 454         pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
 455         if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
 456                 iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);
 457
 458         if (pdev)
 459                 iov->dev = pci_dev_get(pdev);
 460         else
 461                 iov->dev = dev;
 462
 463         mutex_init(&iov->lock);
 464
 465         dev->sriov = iov;
 466         dev->is_physfn = 1;
 467         rc = compute_max_vf_buses(dev);
 468         if (rc)
 469                 goto fail_max_buses;
 470
 471         return 0;
 472
 473 fail_max_buses:
 474         dev->sriov = NULL;
 475         dev->is_physfn = 0;
 476 failed:
 477         for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 478                 res = &dev->resource[i + PCI_IOV_RESOURCES];
 479                 res->flags = 0;
 480         }
 481
 482         kfree(iov);
 483         return rc;
 484 }
 485
 486 static void sriov_release(struct pci_dev *dev)
 487 {
 488         BUG_ON(dev->sriov->num_VFs);
 489
 490         if (dev != dev->sriov->dev)
 491                 pci_dev_put(dev->sriov->dev);
 492
 493         mutex_destroy(&dev->sriov->lock);
 494
 495         kfree(dev->sriov);
 496         dev->sriov = NULL;
 497 }
 498
 499 static void sriov_restore_state(struct pci_dev *dev)
 500 {
 501         int i;
 502         u16 ctrl;
 503         struct pci_sriov *iov = dev->sriov;
 504
 505         pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &ctrl);
 506         if (ctrl & PCI_SRIOV_CTRL_VFE)
 507                 return;
 508
 509         for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++)
 510                 pci_update_resource(dev, i);
 511
 512         pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
 513         pci_iov_set_numvfs(dev, iov->num_VFs);
 514         pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
 515         if (iov->ctrl & PCI_SRIOV_CTRL_VFE)
 516                 msleep(100);
 517 }
 518
 519 /**
 520  * pci_iov_init - initialize the IOV capability
 521  * @dev: the PCI device
 522  *
 523  * Returns 0 on success, or negative on failure.
 524  */
 525 int pci_iov_init(struct pci_dev *dev)
 526 {
 527         int pos;
 528
 529         if (!pci_is_pcie(dev))
 530                 return -ENODEV;
 531
 532         pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
 533         if (pos)
 534                 return sriov_init(dev, pos);
 535
 536         return -ENODEV;
 537 }
 538
 539 /**
 540  * pci_iov_release - release resources used by the IOV capability
 541  * @dev: the PCI device
 542  */
 543 void pci_iov_release(struct pci_dev *dev)
 544 {
 545         if (dev->is_physfn)
 546                 sriov_release(dev);
 547 }
 548
 549 /**
 550  * pci_iov_update_resource - update a VF BAR
 551  * @dev: the PCI device
 552  * @resno: the resource number
 553  *
 554  * Update a VF BAR in the SR-IOV capability of a PF.
 555  */
 556 void pci_iov_update_resource(struct pci_dev *dev, int resno)
 557 {
 558         struct pci_sriov *iov = dev->is_physfn ? dev->sriov : NULL;
 559         struct resource *res = dev->resource + resno;
 560         int vf_bar = resno - PCI_IOV_RESOURCES;
 561         struct pci_bus_region region;
 562         u16 cmd;
 563         u32 new;
 564         int reg;
 565
 566         /*
 567          * The generic pci_restore_bars() path calls this for all devices,
 568          * including VFs and non-SR-IOV devices.  If this is not a PF, we
 569          * have nothing to do.
 570          */
 571         if (!iov)
 572                 return;
 573
 574         pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &cmd);
 575         if ((cmd & PCI_SRIOV_CTRL_VFE) && (cmd & PCI_SRIOV_CTRL_MSE)) {
 576                 dev_WARN(&dev->dev, "can't update enabled VF BAR%d %pR\n",
 577                          vf_bar, res);
 578                 return;
 579         }
 580
 581         /*
 582          * Ignore unimplemented BARs, unused resource slots for 64-bit
 583          * BARs, and non-movable resources, e.g., those described via
 584          * Enhanced Allocation.
 585          */
 586         if (!res->flags)
 587                 return;
 588
 589         if (res->flags & IORESOURCE_UNSET)
 590                 return;
 591
 592         if (res->flags & IORESOURCE_PCI_FIXED)
 593                 return;
 594
 595         pcibios_resource_to_bus(dev->bus, &region, res);
 596         new = region.start;
 597         new |= res->flags & ~PCI_BASE_ADDRESS_MEM_MASK;
 598
 599         reg = iov->pos + PCI_SRIOV_BAR + 4 * vf_bar;
 600         pci_write_config_dword(dev, reg, new);
 601         if (res->flags & IORESOURCE_MEM_64) {
 602                 new = region.start >> 16 >> 16;
 603                 pci_write_config_dword(dev, reg + 4, new);
 604         }
 605 }
 606
 607 resource_size_t __weak pcibios_iov_resource_alignment(struct pci_dev *dev,
 608                                                       int resno)
 609 {
 610         return pci_iov_resource_size(dev, resno);
 611 }
 612
 613 /**
 614  * pci_sriov_resource_alignment - get resource alignment for VF BAR
 615  * @dev: the PCI device
 616  * @resno: the resource number
 617  *
 618  * Returns the alignment of the VF BAR found in the SR-IOV capability.
 619  * This is not the same as the resource size which is defined as
 620  * the VF BAR size multiplied by the number of VFs.  The alignment
 621  * is just the VF BAR size.
 622  */
 623 resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
 624 {
 625         return pcibios_iov_resource_alignment(dev, resno);
 626 }
 627
 628 /**
 629  * pci_restore_iov_state - restore the state of the IOV capability
 630  * @dev: the PCI device
 631  */
 632 void pci_restore_iov_state(struct pci_dev *dev)
 633 {
 634         if (dev->is_physfn)
 635                 sriov_restore_state(dev);
 636 }
 637
 638 /**
 639  * pci_iov_bus_range - find bus range used by Virtual Function
 640  * @bus: the PCI bus
 641  *
 642  * Returns max number of buses (exclude current one) used by Virtual
 643  * Functions.
 644  */
 645 int pci_iov_bus_range(struct pci_bus *bus)
 646 {
 647         int max = 0;
 648         struct pci_dev *dev;
 649
 650         list_for_each_entry(dev, &bus->devices, bus_list) {
 651                 if (!dev->is_physfn)
 652                         continue;
 653                 if (dev->sriov->max_VF_buses > max)
 654                         max = dev->sriov->max_VF_buses;
 655         }
 656
 657         return max ? max - bus->number : 0;
 658 }
 659
 660 /**
 661  * pci_enable_sriov - enable the SR-IOV capability
 662  * @dev: the PCI device
 663  * @nr_virtfn: number of virtual functions to enable
 664  *
 665  * Returns 0 on success, or negative on failure.
 666  */
 667 int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
 668 {
 669         might_sleep();
 670
 671         if (!dev->is_physfn)
 672                 return -ENOSYS;
 673
 674         return sriov_enable(dev, nr_virtfn);
 675 }
 676 EXPORT_SYMBOL_GPL(pci_enable_sriov);
 677
 678 /**
 679  * pci_disable_sriov - disable the SR-IOV capability
 680  * @dev: the PCI device
 681  */
 682 void pci_disable_sriov(struct pci_dev *dev)
 683 {
 684         might_sleep();
 685
 686         if (!dev->is_physfn)
 687                 return;
 688
 689         sriov_disable(dev);
 690 }
 691 EXPORT_SYMBOL_GPL(pci_disable_sriov);
 692
 693 /**
 694  * pci_num_vf - return number of VFs associated with a PF device_release_driver
 695  * @dev: the PCI device
 696  *
 697  * Returns number of VFs, or 0 if SR-IOV is not enabled.
 698  */
 699 int pci_num_vf(struct pci_dev *dev)
 700 {
 701         if (!dev->is_physfn)
 702                 return 0;
 703
 704         return dev->sriov->num_VFs;
 705 }
 706 EXPORT_SYMBOL_GPL(pci_num_vf);
 707
 708 /**
 709  * pci_vfs_assigned - returns number of VFs are assigned to a guest
 710  * @dev: the PCI device
 711  *
 712  * Returns number of VFs belonging to this device that are assigned to a guest.
 713  * If device is not a physical function returns 0.
 714  */
 715 int pci_vfs_assigned(struct pci_dev *dev)
 716 {
 717         struct pci_dev *vfdev;
 718         unsigned int vfs_assigned = 0;
 719         unsigned short dev_id;
 720
 721         /* only search if we are a PF */
 722         if (!dev->is_physfn)
 723                 return 0;
 724
 725         /*
 726          * determine the device ID for the VFs, the vendor ID will be the
 727          * same as the PF so there is no need to check for that one
 728          */
 729         pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_VF_DID, &dev_id);
 730
 731         /* loop through all the VFs to see if we own any that are assigned */
 732         vfdev = pci_get_device(dev->vendor, dev_id, NULL);
 733         while (vfdev) {
 734                 /*
 735                  * It is considered assigned if it is a virtual function with
 736                  * our dev as the physical function and the assigned bit is set
 737                  */
 738                 if (vfdev->is_virtfn && (vfdev->physfn == dev) &&
 739                         pci_is_dev_assigned(vfdev))
 740                         vfs_assigned++;
 741
 742                 vfdev = pci_get_device(dev->vendor, dev_id, vfdev);
 743         }
 744
 745         return vfs_assigned;
 746 }
 747 EXPORT_SYMBOL_GPL(pci_vfs_assigned);
 748
 749 /**
 750  * pci_sriov_set_totalvfs -- reduce the TotalVFs available
 751  * @dev: the PCI PF device
 752  * @numvfs: number that should be used for TotalVFs supported
 753  *
 754  * Should be called from PF driver's probe routine with
 755  * device's mutex held.
 756  *
 757  * Returns 0 if PF is an SRIOV-capable device and
 758  * value of numvfs valid. If not a PF return -ENOSYS;
 759  * if numvfs is invalid return -EINVAL;
 760  * if VFs already enabled, return -EBUSY.
 761  */
 762 int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
 763 {
 764         if (!dev->is_physfn)
 765                 return -ENOSYS;
 766         if (numvfs > dev->sriov->total_VFs)
 767                 return -EINVAL;
 768
 769         /* Shouldn't change if VFs already enabled */
 770         if (dev->sriov->ctrl & PCI_SRIOV_CTRL_VFE)
 771                 return -EBUSY;
 772         else
 773                 dev->sriov->driver_max_VFs = numvfs;
 774
 775         return 0;
 776 }
 777 EXPORT_SYMBOL_GPL(pci_sriov_set_totalvfs);
 778
 779 /**
 780  * pci_sriov_get_totalvfs -- get total VFs supported on this device
 781  * @dev: the PCI PF device
 782  *
 783  * For a PCIe device with SRIOV support, return the PCIe
 784  * SRIOV capability value of TotalVFs or the value of driver_max_VFs
 785  * if the driver reduced it.  Otherwise 0.
 786  */
 787 int pci_sriov_get_totalvfs(struct pci_dev *dev)
 788 {
 789         if (!dev->is_physfn)
 790                 return 0;
 791
 792         if (dev->sriov->driver_max_VFs)
 793                 return dev->sriov->driver_max_VFs;
 794
 795         return dev->sriov->total_VFs;
 796 }
 797 EXPORT_SYMBOL_GPL(pci_sriov_get_totalvfs);