drivers/vfio/pci/vfio_pci.c

   1 /*
   2  * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
   3  *     Author: Alex Williamson <alex.williamson@redhat.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Derived from original vfio:
  10  * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
  11  * Author: Tom Lyon, pugs@cisco.com
  12  */
  13
  14 #include <linux/device.h>
  15 #include <linux/eventfd.h>
  16 #include <linux/file.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/iommu.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <linux/notifier.h>
  22 #include <linux/pci.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/slab.h>
  25 #include <linux/types.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/vfio.h>
  28
  29 #include "vfio_pci_private.h"
  30
  31 #define DRIVER_VERSION  "0.2"
  32 #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
  33 #define DRIVER_DESC     "VFIO PCI - User Level meta-driver"
  34
  35 static bool nointxmask;
  36 module_param_named(nointxmask, nointxmask, bool, S_IRUGO | S_IWUSR);
  37 MODULE_PARM_DESC(nointxmask,
  38                   "Disable support for PCI 2.3 style INTx masking.  If this resolves problems for specific devices, report lspci -vvvxxx to linux-pci@vger.kernel.org so the device can be fixed automatically via the broken_intx_masking flag.");
  39
  40 static DEFINE_MUTEX(driver_lock);
  41
  42 static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev);
  43
  44 static int vfio_pci_enable(struct vfio_pci_device *vdev)
  45 {
  46         struct pci_dev *pdev = vdev->pdev;
  47         int ret;
  48         u16 cmd;
  49         u8 msix_pos;
  50
  51         /* Don't allow our initial saved state to include busmaster */
  52         pci_clear_master(pdev);
  53
  54         ret = pci_enable_device(pdev);
  55         if (ret)
  56                 return ret;
  57
  58         vdev->reset_works = (pci_reset_function(pdev) == 0);
  59         pci_save_state(pdev);
  60         vdev->pci_saved_state = pci_store_saved_state(pdev);
  61         if (!vdev->pci_saved_state)
  62                 pr_debug("%s: Couldn't store %s saved state\n",
  63                          __func__, dev_name(&pdev->dev));
  64
  65         ret = vfio_config_init(vdev);
  66         if (ret) {
  67                 kfree(vdev->pci_saved_state);
  68                 vdev->pci_saved_state = NULL;
  69                 pci_disable_device(pdev);
  70                 return ret;
  71         }
  72
  73         if (likely(!nointxmask))
  74                 vdev->pci_2_3 = pci_intx_mask_supported(pdev);
  75
  76         pci_read_config_word(pdev, PCI_COMMAND, &cmd);
  77         if (vdev->pci_2_3 && (cmd & PCI_COMMAND_INTX_DISABLE)) {
  78                 cmd &= ~PCI_COMMAND_INTX_DISABLE;
  79                 pci_write_config_word(pdev, PCI_COMMAND, cmd);
  80         }
  81
  82         msix_pos = pdev->msix_cap;
  83         if (msix_pos) {
  84                 u16 flags;
  85                 u32 table;
  86
  87                 pci_read_config_word(pdev, msix_pos + PCI_MSIX_FLAGS, &flags);
  88                 pci_read_config_dword(pdev, msix_pos + PCI_MSIX_TABLE, &table);
  89
  90                 vdev->msix_bar = table & PCI_MSIX_TABLE_BIR;
  91                 vdev->msix_offset = table & PCI_MSIX_TABLE_OFFSET;
  92                 vdev->msix_size = ((flags & PCI_MSIX_FLAGS_QSIZE) + 1) * 16;
  93         } else
  94                 vdev->msix_bar = 0xFF;
  95
  96 #ifdef CONFIG_VFIO_PCI_VGA
  97         if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
  98                 vdev->has_vga = true;
  99 #endif
 100
 101         return 0;
 102 }
 103
 104 static void vfio_pci_disable(struct vfio_pci_device *vdev)
 105 {
 106         struct pci_dev *pdev = vdev->pdev;
 107         int bar;
 108
 109         /* Stop the device from further DMA */
 110         pci_clear_master(pdev);
 111
 112         vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE |
 113                                 VFIO_IRQ_SET_ACTION_TRIGGER,
 114                                 vdev->irq_type, 0, 0, NULL);
 115
 116         vdev->virq_disabled = false;
 117
 118         vfio_config_free(vdev);
 119
 120         for (bar = PCI_STD_RESOURCES; bar <= PCI_STD_RESOURCE_END; bar++) {
 121                 if (!vdev->barmap[bar])
 122                         continue;
 123                 pci_iounmap(pdev, vdev->barmap[bar]);
 124                 pci_release_selected_regions(pdev, 1 << bar);
 125                 vdev->barmap[bar] = NULL;
 126         }
 127
 128         vdev->needs_reset = true;
 129
 130         /*
 131          * If we have saved state, restore it.  If we can reset the device,
 132          * even better.  Resetting with current state seems better than
 133          * nothing, but saving and restoring current state without reset
 134          * is just busy work.
 135          */
 136         if (pci_load_and_free_saved_state(pdev, &vdev->pci_saved_state)) {
 137                 pr_info("%s: Couldn't reload %s saved state\n",
 138                         __func__, dev_name(&pdev->dev));
 139
 140                 if (!vdev->reset_works)
 141                         goto out;
 142
 143                 pci_save_state(pdev);
 144         }
 145
 146         /*
 147          * Disable INTx and MSI, presumably to avoid spurious interrupts
 148          * during reset.  Stolen from pci_reset_function()
 149          */
 150         pci_write_config_word(pdev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
 151
 152         /*
 153          * Try to reset the device.  The success of this is dependent on
 154          * being able to lock the device, which is not always possible.
 155          */
 156         if (vdev->reset_works) {
 157                 int ret = pci_try_reset_function(pdev);
 158                 if (ret)
 159                         pr_warn("%s: Failed to reset device %s (%d)\n",
 160                                 __func__, dev_name(&pdev->dev), ret);
 161                 else
 162                         vdev->needs_reset = false;
 163         }
 164
 165         pci_restore_state(pdev);
 166 out:
 167         pci_disable_device(pdev);
 168
 169         vfio_pci_try_bus_reset(vdev);
 170 }
 171
 172 static void vfio_pci_release(void *device_data)
 173 {
 174         struct vfio_pci_device *vdev = device_data;
 175
 176         mutex_lock(&driver_lock);
 177
 178         if (!(--vdev->refcnt)) {
 179                 vfio_spapr_pci_eeh_release(vdev->pdev);
 180                 vfio_pci_disable(vdev);
 181         }
 182
 183         mutex_unlock(&driver_lock);
 184
 185         module_put(THIS_MODULE);
 186 }
 187
 188 static int vfio_pci_open(void *device_data)
 189 {
 190         struct vfio_pci_device *vdev = device_data;
 191         int ret = 0;
 192
 193         if (!try_module_get(THIS_MODULE))
 194                 return -ENODEV;
 195
 196         mutex_lock(&driver_lock);
 197
 198         if (!vdev->refcnt) {
 199                 ret = vfio_pci_enable(vdev);
 200                 if (ret)
 201                         goto error;
 202
 203                 vfio_spapr_pci_eeh_open(vdev->pdev);
 204         }
 205         vdev->refcnt++;
 206 error:
 207         mutex_unlock(&driver_lock);
 208         if (ret)
 209                 module_put(THIS_MODULE);
 210         return ret;
 211 }
 212
 213 static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)
 214 {
 215         if (irq_type == VFIO_PCI_INTX_IRQ_INDEX) {
 216                 u8 pin;
 217                 pci_read_config_byte(vdev->pdev, PCI_INTERRUPT_PIN, &pin);
 218                 if (pin)
 219                         return 1;
 220
 221         } else if (irq_type == VFIO_PCI_MSI_IRQ_INDEX) {
 222                 u8 pos;
 223                 u16 flags;
 224
 225                 pos = vdev->pdev->msi_cap;
 226                 if (pos) {
 227                         pci_read_config_word(vdev->pdev,
 228                                              pos + PCI_MSI_FLAGS, &flags);
 229                         return 1 << ((flags & PCI_MSI_FLAGS_QMASK) >> 1);
 230                 }
 231         } else if (irq_type == VFIO_PCI_MSIX_IRQ_INDEX) {
 232                 u8 pos;
 233                 u16 flags;
 234
 235                 pos = vdev->pdev->msix_cap;
 236                 if (pos) {
 237                         pci_read_config_word(vdev->pdev,
 238                                              pos + PCI_MSIX_FLAGS, &flags);
 239
 240                         return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
 241                 }
 242         } else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX)
 243                 if (pci_is_pcie(vdev->pdev))
 244                         return 1;
 245
 246         return 0;
 247 }
 248
 249 static int vfio_pci_count_devs(struct pci_dev *pdev, void *data)
 250 {
 251         (*(int *)data)++;
 252         return 0;
 253 }
 254
 255 struct vfio_pci_fill_info {
 256         int max;
 257         int cur;
 258         struct vfio_pci_dependent_device *devices;
 259 };
 260
 261 static int vfio_pci_fill_devs(struct pci_dev *pdev, void *data)
 262 {
 263         struct vfio_pci_fill_info *fill = data;
 264         struct iommu_group *iommu_group;
 265
 266         if (fill->cur == fill->max)
 267                 return -EAGAIN; /* Something changed, try again */
 268
 269         iommu_group = iommu_group_get(&pdev->dev);
 270         if (!iommu_group)
 271                 return -EPERM; /* Cannot reset non-isolated devices */
 272
 273         fill->devices[fill->cur].group_id = iommu_group_id(iommu_group);
 274         fill->devices[fill->cur].segment = pci_domain_nr(pdev->bus);
 275         fill->devices[fill->cur].bus = pdev->bus->number;
 276         fill->devices[fill->cur].devfn = pdev->devfn;
 277         fill->cur++;
 278         iommu_group_put(iommu_group);
 279         return 0;
 280 }
 281
 282 struct vfio_pci_group_entry {
 283         struct vfio_group *group;
 284         int id;
 285 };
 286
 287 struct vfio_pci_group_info {
 288         int count;
 289         struct vfio_pci_group_entry *groups;
 290 };
 291
 292 static int vfio_pci_validate_devs(struct pci_dev *pdev, void *data)
 293 {
 294         struct vfio_pci_group_info *info = data;
 295         struct iommu_group *group;
 296         int id, i;
 297
 298         group = iommu_group_get(&pdev->dev);
 299         if (!group)
 300                 return -EPERM;
 301
 302         id = iommu_group_id(group);
 303
 304         for (i = 0; i < info->count; i++)
 305                 if (info->groups[i].id == id)
 306                         break;
 307
 308         iommu_group_put(group);
 309
 310         return (i == info->count) ? -EINVAL : 0;
 311 }
 312
 313 static bool vfio_pci_dev_below_slot(struct pci_dev *pdev, struct pci_slot *slot)
 314 {
 315         for (; pdev; pdev = pdev->bus->self)
 316                 if (pdev->bus == slot->bus)
 317                         return (pdev->slot == slot);
 318         return false;
 319 }
 320
 321 struct vfio_pci_walk_info {
 322         int (*fn)(struct pci_dev *, void *data);
 323         void *data;
 324         struct pci_dev *pdev;
 325         bool slot;
 326         int ret;
 327 };
 328
 329 static int vfio_pci_walk_wrapper(struct pci_dev *pdev, void *data)
 330 {
 331         struct vfio_pci_walk_info *walk = data;
 332
 333         if (!walk->slot || vfio_pci_dev_below_slot(pdev, walk->pdev->slot))
 334                 walk->ret = walk->fn(pdev, walk->data);
 335
 336         return walk->ret;
 337 }
 338
 339 static int vfio_pci_for_each_slot_or_bus(struct pci_dev *pdev,
 340                                          int (*fn)(struct pci_dev *,
 341                                                    void *data), void *data,
 342                                          bool slot)
 343 {
 344         struct vfio_pci_walk_info walk = {
 345                 .fn = fn, .data = data, .pdev = pdev, .slot = slot, .ret = 0,
 346         };
 347
 348         pci_walk_bus(pdev->bus, vfio_pci_walk_wrapper, &walk);
 349
 350         return walk.ret;
 351 }
 352
 353 static long vfio_pci_ioctl(void *device_data,
 354                            unsigned int cmd, unsigned long arg)
 355 {
 356         struct vfio_pci_device *vdev = device_data;
 357         unsigned long minsz;
 358
 359         if (cmd == VFIO_DEVICE_GET_INFO) {
 360                 struct vfio_device_info info;
 361
 362                 minsz = offsetofend(struct vfio_device_info, num_irqs);
 363
 364                 if (copy_from_user(&info, (void __user *)arg, minsz))
 365                         return -EFAULT;
 366
 367                 if (info.argsz < minsz)
 368                         return -EINVAL;
 369
 370                 info.flags = VFIO_DEVICE_FLAGS_PCI;
 371
 372                 if (vdev->reset_works)
 373                         info.flags |= VFIO_DEVICE_FLAGS_RESET;
 374
 375                 info.num_regions = VFIO_PCI_NUM_REGIONS;
 376                 info.num_irqs = VFIO_PCI_NUM_IRQS;
 377
 378                 return copy_to_user((void __user *)arg, &info, minsz);
 379
 380         } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
 381                 struct pci_dev *pdev = vdev->pdev;
 382                 struct vfio_region_info info;
 383
 384                 minsz = offsetofend(struct vfio_region_info, offset);
 385
 386                 if (copy_from_user(&info, (void __user *)arg, minsz))
 387                         return -EFAULT;
 388
 389                 if (info.argsz < minsz)
 390                         return -EINVAL;
 391
 392                 switch (info.index) {
 393                 case VFIO_PCI_CONFIG_REGION_INDEX:
 394                         info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
 395                         info.size = pdev->cfg_size;
 396                         info.flags = VFIO_REGION_INFO_FLAG_READ |
 397                                      VFIO_REGION_INFO_FLAG_WRITE;
 398                         break;
 399                 case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
 400                         info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
 401                         info.size = pci_resource_len(pdev, info.index);
 402                         if (!info.size) {
 403                                 info.flags = 0;
 404                                 break;
 405                         }
 406
 407                         info.flags = VFIO_REGION_INFO_FLAG_READ |
 408                                      VFIO_REGION_INFO_FLAG_WRITE;
 409                         if (pci_resource_flags(pdev, info.index) &
 410                             IORESOURCE_MEM && info.size >= PAGE_SIZE)
 411                                 info.flags |= VFIO_REGION_INFO_FLAG_MMAP;
 412                         break;
 413                 case VFIO_PCI_ROM_REGION_INDEX:
 414                 {
 415                         void __iomem *io;
 416                         size_t size;
 417
 418                         info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
 419                         info.flags = 0;
 420
 421                         /* Report the BAR size, not the ROM size */
 422                         info.size = pci_resource_len(pdev, info.index);
 423                         if (!info.size)
 424                                 break;
 425
 426                         /* Is it really there? */
 427                         io = pci_map_rom(pdev, &size);
 428                         if (!io || !size) {
 429                                 info.size = 0;
 430                                 break;
 431                         }
 432                         pci_unmap_rom(pdev, io);
 433
 434                         info.flags = VFIO_REGION_INFO_FLAG_READ;
 435                         break;
 436                 }
 437                 case VFIO_PCI_VGA_REGION_INDEX:
 438                         if (!vdev->has_vga)
 439                                 return -EINVAL;
 440
 441                         info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
 442                         info.size = 0xc0000;
 443                         info.flags = VFIO_REGION_INFO_FLAG_READ |
 444                                      VFIO_REGION_INFO_FLAG_WRITE;
 445
 446                         break;
 447                 default:
 448                         return -EINVAL;
 449                 }
 450
 451                 return copy_to_user((void __user *)arg, &info, minsz);
 452
 453         } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
 454                 struct vfio_irq_info info;
 455
 456                 minsz = offsetofend(struct vfio_irq_info, count);
 457
 458                 if (copy_from_user(&info, (void __user *)arg, minsz))
 459                         return -EFAULT;
 460
 461                 if (info.argsz < minsz || info.index >= VFIO_PCI_NUM_IRQS)
 462                         return -EINVAL;
 463
 464                 switch (info.index) {
 465                 case VFIO_PCI_INTX_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
 466                         break;
 467                 case VFIO_PCI_ERR_IRQ_INDEX:
 468                         if (pci_is_pcie(vdev->pdev))
 469                                 break;
 470                 /* pass thru to return error */
 471                 default:
 472                         return -EINVAL;
 473                 }
 474
 475                 info.flags = VFIO_IRQ_INFO_EVENTFD;
 476
 477                 info.count = vfio_pci_get_irq_count(vdev, info.index);
 478
 479                 if (info.index == VFIO_PCI_INTX_IRQ_INDEX)
 480                         info.flags |= (VFIO_IRQ_INFO_MASKABLE |
 481                                        VFIO_IRQ_INFO_AUTOMASKED);
 482                 else
 483                         info.flags |= VFIO_IRQ_INFO_NORESIZE;
 484
 485                 return copy_to_user((void __user *)arg, &info, minsz);
 486
 487         } else if (cmd == VFIO_DEVICE_SET_IRQS) {
 488                 struct vfio_irq_set hdr;
 489                 u8 *data = NULL;
 490                 int ret = 0;
 491
 492                 minsz = offsetofend(struct vfio_irq_set, count);
 493
 494                 if (copy_from_user(&hdr, (void __user *)arg, minsz))
 495                         return -EFAULT;
 496
 497                 if (hdr.argsz < minsz || hdr.index >= VFIO_PCI_NUM_IRQS ||
 498                     hdr.flags & ~(VFIO_IRQ_SET_DATA_TYPE_MASK |
 499                                   VFIO_IRQ_SET_ACTION_TYPE_MASK))
 500                         return -EINVAL;
 501
 502                 if (!(hdr.flags & VFIO_IRQ_SET_DATA_NONE)) {
 503                         size_t size;
 504                         int max = vfio_pci_get_irq_count(vdev, hdr.index);
 505
 506                         if (hdr.flags & VFIO_IRQ_SET_DATA_BOOL)
 507                                 size = sizeof(uint8_t);
 508                         else if (hdr.flags & VFIO_IRQ_SET_DATA_EVENTFD)
 509                                 size = sizeof(int32_t);
 510                         else
 511                                 return -EINVAL;
 512
 513                         if (hdr.argsz - minsz < hdr.count * size ||
 514                             hdr.start >= max || hdr.start + hdr.count > max)
 515                                 return -EINVAL;
 516
 517                         data = memdup_user((void __user *)(arg + minsz),
 518                                            hdr.count * size);
 519                         if (IS_ERR(data))
 520                                 return PTR_ERR(data);
 521                 }
 522
 523                 mutex_lock(&vdev->igate);
 524
 525                 ret = vfio_pci_set_irqs_ioctl(vdev, hdr.flags, hdr.index,
 526                                               hdr.start, hdr.count, data);
 527
 528                 mutex_unlock(&vdev->igate);
 529                 kfree(data);
 530
 531                 return ret;
 532
 533         } else if (cmd == VFIO_DEVICE_RESET) {
 534                 return vdev->reset_works ?
 535                         pci_try_reset_function(vdev->pdev) : -EINVAL;
 536
 537         } else if (cmd == VFIO_DEVICE_GET_PCI_HOT_RESET_INFO) {
 538                 struct vfio_pci_hot_reset_info hdr;
 539                 struct vfio_pci_fill_info fill = { 0 };
 540                 struct vfio_pci_dependent_device *devices = NULL;
 541                 bool slot = false;
 542                 int ret = 0;
 543
 544                 minsz = offsetofend(struct vfio_pci_hot_reset_info, count);
 545
 546                 if (copy_from_user(&hdr, (void __user *)arg, minsz))
 547                         return -EFAULT;
 548
 549                 if (hdr.argsz < minsz)
 550                         return -EINVAL;
 551
 552                 hdr.flags = 0;
 553
 554                 /* Can we do a slot or bus reset or neither? */
 555                 if (!pci_probe_reset_slot(vdev->pdev->slot))
 556                         slot = true;
 557                 else if (pci_probe_reset_bus(vdev->pdev->bus))
 558                         return -ENODEV;
 559
 560                 /* How many devices are affected? */
 561                 ret = vfio_pci_for_each_slot_or_bus(vdev->pdev,
 562                                                     vfio_pci_count_devs,
 563                                                     &fill.max, slot);
 564                 if (ret)
 565                         return ret;
 566
 567                 WARN_ON(!fill.max); /* Should always be at least one */
 568
 569                 /*
 570                  * If there's enough space, fill it now, otherwise return
 571                  * -ENOSPC and the number of devices affected.
 572                  */
 573                 if (hdr.argsz < sizeof(hdr) + (fill.max * sizeof(*devices))) {
 574                         ret = -ENOSPC;
 575                         hdr.count = fill.max;
 576                         goto reset_info_exit;
 577                 }
 578
 579                 devices = kcalloc(fill.max, sizeof(*devices), GFP_KERNEL);
 580                 if (!devices)
 581                         return -ENOMEM;
 582
 583                 fill.devices = devices;
 584
 585                 ret = vfio_pci_for_each_slot_or_bus(vdev->pdev,
 586                                                     vfio_pci_fill_devs,
 587                                                     &fill, slot);
 588
 589                 /*
 590                  * If a device was removed between counting and filling,
 591                  * we may come up short of fill.max.  If a device was
 592                  * added, we'll have a return of -EAGAIN above.
 593                  */
 594                 if (!ret)
 595                         hdr.count = fill.cur;
 596
 597 reset_info_exit:
 598                 if (copy_to_user((void __user *)arg, &hdr, minsz))
 599                         ret = -EFAULT;
 600
 601                 if (!ret) {
 602                         if (copy_to_user((void __user *)(arg + minsz), devices,
 603                                          hdr.count * sizeof(*devices)))
 604                                 ret = -EFAULT;
 605                 }
 606
 607                 kfree(devices);
 608                 return ret;
 609
 610         } else if (cmd == VFIO_DEVICE_PCI_HOT_RESET) {
 611                 struct vfio_pci_hot_reset hdr;
 612                 int32_t *group_fds;
 613                 struct vfio_pci_group_entry *groups;
 614                 struct vfio_pci_group_info info;
 615                 bool slot = false;
 616                 int i, count = 0, ret = 0;
 617
 618                 minsz = offsetofend(struct vfio_pci_hot_reset, count);
 619
 620                 if (copy_from_user(&hdr, (void __user *)arg, minsz))
 621                         return -EFAULT;
 622
 623                 if (hdr.argsz < minsz || hdr.flags)
 624                         return -EINVAL;
 625
 626                 /* Can we do a slot or bus reset or neither? */
 627                 if (!pci_probe_reset_slot(vdev->pdev->slot))
 628                         slot = true;
 629                 else if (pci_probe_reset_bus(vdev->pdev->bus))
 630                         return -ENODEV;
 631
 632                 /*
 633                  * We can't let userspace give us an arbitrarily large
 634                  * buffer to copy, so verify how many we think there
 635                  * could be.  Note groups can have multiple devices so
 636                  * one group per device is the max.
 637                  */
 638                 ret = vfio_pci_for_each_slot_or_bus(vdev->pdev,
 639                                                     vfio_pci_count_devs,
 640                                                     &count, slot);
 641                 if (ret)
 642                         return ret;
 643
 644                 /* Somewhere between 1 and count is OK */
 645                 if (!hdr.count || hdr.count > count)
 646                         return -EINVAL;
 647
 648                 group_fds = kcalloc(hdr.count, sizeof(*group_fds), GFP_KERNEL);
 649                 groups = kcalloc(hdr.count, sizeof(*groups), GFP_KERNEL);
 650                 if (!group_fds || !groups) {
 651                         kfree(group_fds);
 652                         kfree(groups);
 653                         return -ENOMEM;
 654                 }
 655
 656                 if (copy_from_user(group_fds, (void __user *)(arg + minsz),
 657                                    hdr.count * sizeof(*group_fds))) {
 658                         kfree(group_fds);
 659                         kfree(groups);
 660                         return -EFAULT;
 661                 }
 662
 663                 /*
 664                  * For each group_fd, get the group through the vfio external
 665                  * user interface and store the group and iommu ID.  This
 666                  * ensures the group is held across the reset.
 667                  */
 668                 for (i = 0; i < hdr.count; i++) {
 669                         struct vfio_group *group;
 670                         struct fd f = fdget(group_fds[i]);
 671                         if (!f.file) {
 672                                 ret = -EBADF;
 673                                 break;
 674                         }
 675
 676                         group = vfio_group_get_external_user(f.file);
 677                         fdput(f);
 678                         if (IS_ERR(group)) {
 679                                 ret = PTR_ERR(group);
 680                                 break;
 681                         }
 682
 683                         groups[i].group = group;
 684                         groups[i].id = vfio_external_user_iommu_id(group);
 685                 }
 686
 687                 kfree(group_fds);
 688
 689                 /* release reference to groups on error */
 690                 if (ret)
 691                         goto hot_reset_release;
 692
 693                 info.count = hdr.count;
 694                 info.groups = groups;
 695
 696                 /*
 697                  * Test whether all the affected devices are contained
 698                  * by the set of groups provided by the user.
 699                  */
 700                 ret = vfio_pci_for_each_slot_or_bus(vdev->pdev,
 701                                                     vfio_pci_validate_devs,
 702                                                     &info, slot);
 703                 if (!ret)
 704                         /* User has access, do the reset */
 705                         ret = slot ? pci_try_reset_slot(vdev->pdev->slot) :
 706                                      pci_try_reset_bus(vdev->pdev->bus);
 707
 708 hot_reset_release:
 709                 for (i--; i >= 0; i--)
 710                         vfio_group_put_external_user(groups[i].group);
 711
 712                 kfree(groups);
 713                 return ret;
 714         }
 715
 716         return -ENOTTY;
 717 }
 718
 719 static ssize_t vfio_pci_rw(void *device_data, char __user *buf,
 720                            size_t count, loff_t *ppos, bool iswrite)
 721 {
 722         unsigned int index = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
 723         struct vfio_pci_device *vdev = device_data;
 724
 725         if (index >= VFIO_PCI_NUM_REGIONS)
 726                 return -EINVAL;
 727
 728         switch (index) {
 729         case VFIO_PCI_CONFIG_REGION_INDEX:
 730                 return vfio_pci_config_rw(vdev, buf, count, ppos, iswrite);
 731
 732         case VFIO_PCI_ROM_REGION_INDEX:
 733                 if (iswrite)
 734                         return -EINVAL;
 735                 return vfio_pci_bar_rw(vdev, buf, count, ppos, false);
 736
 737         case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
 738                 return vfio_pci_bar_rw(vdev, buf, count, ppos, iswrite);
 739
 740         case VFIO_PCI_VGA_REGION_INDEX:
 741                 return vfio_pci_vga_rw(vdev, buf, count, ppos, iswrite);
 742         }
 743
 744         return -EINVAL;
 745 }
 746
 747 static ssize_t vfio_pci_read(void *device_data, char __user *buf,
 748                              size_t count, loff_t *ppos)
 749 {
 750         if (!count)
 751                 return 0;
 752
 753         return vfio_pci_rw(device_data, buf, count, ppos, false);
 754 }
 755
 756 static ssize_t vfio_pci_write(void *device_data, const char __user *buf,
 757                               size_t count, loff_t *ppos)
 758 {
 759         if (!count)
 760                 return 0;
 761
 762         return vfio_pci_rw(device_data, (char __user *)buf, count, ppos, true);
 763 }
 764
 765 static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma)
 766 {
 767         struct vfio_pci_device *vdev = device_data;
 768         struct pci_dev *pdev = vdev->pdev;
 769         unsigned int index;
 770         u64 phys_len, req_len, pgoff, req_start;
 771         int ret;
 772
 773         index = vma->vm_pgoff >> (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT);
 774
 775         if (vma->vm_end < vma->vm_start)
 776                 return -EINVAL;
 777         if ((vma->vm_flags & VM_SHARED) == 0)
 778                 return -EINVAL;
 779         if (index >= VFIO_PCI_ROM_REGION_INDEX)
 780                 return -EINVAL;
 781         if (!(pci_resource_flags(pdev, index) & IORESOURCE_MEM))
 782                 return -EINVAL;
 783
 784         phys_len = pci_resource_len(pdev, index);
 785         req_len = vma->vm_end - vma->vm_start;
 786         pgoff = vma->vm_pgoff &
 787                 ((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
 788         req_start = pgoff << PAGE_SHIFT;
 789
 790         if (phys_len < PAGE_SIZE || req_start + req_len > phys_len)
 791                 return -EINVAL;
 792
 793         if (index == vdev->msix_bar) {
 794                 /*
 795                  * Disallow mmaps overlapping the MSI-X table; users don't
 796                  * get to touch this directly.  We could find somewhere
 797                  * else to map the overlap, but page granularity is only
 798                  * a recommendation, not a requirement, so the user needs
 799                  * to know which bits are real.  Requiring them to mmap
 800                  * around the table makes that clear.
 801                  */
 802
 803                 /* If neither entirely above nor below, then it overlaps */
 804                 if (!(req_start >= vdev->msix_offset + vdev->msix_size ||
 805                       req_start + req_len <= vdev->msix_offset))
 806                         return -EINVAL;
 807         }
 808
 809         /*
 810          * Even though we don't make use of the barmap for the mmap,
 811          * we need to request the region and the barmap tracks that.
 812          */
 813         if (!vdev->barmap[index]) {
 814                 ret = pci_request_selected_regions(pdev,
 815                                                    1 << index, "vfio-pci");
 816                 if (ret)
 817                         return ret;
 818
 819                 vdev->barmap[index] = pci_iomap(pdev, index, 0);
 820         }
 821
 822         vma->vm_private_data = vdev;
 823         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 824         vma->vm_pgoff = (pci_resource_start(pdev, index) >> PAGE_SHIFT) + pgoff;
 825
 826         return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
 827                                req_len, vma->vm_page_prot);
 828 }
 829
 830 static const struct vfio_device_ops vfio_pci_ops = {
 831         .name           = "vfio-pci",
 832         .open           = vfio_pci_open,
 833         .release        = vfio_pci_release,
 834         .ioctl          = vfio_pci_ioctl,
 835         .read           = vfio_pci_read,
 836         .write          = vfio_pci_write,
 837         .mmap           = vfio_pci_mmap,
 838 };
 839
 840 static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 841 {
 842         u8 type;
 843         struct vfio_pci_device *vdev;
 844         struct iommu_group *group;
 845         int ret;
 846
 847         pci_read_config_byte(pdev, PCI_HEADER_TYPE, &type);
 848         if ((type & PCI_HEADER_TYPE) != PCI_HEADER_TYPE_NORMAL)
 849                 return -EINVAL;
 850
 851         group = iommu_group_get(&pdev->dev);
 852         if (!group)
 853                 return -EINVAL;
 854
 855         vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 856         if (!vdev) {
 857                 iommu_group_put(group);
 858                 return -ENOMEM;
 859         }
 860
 861         vdev->pdev = pdev;
 862         vdev->irq_type = VFIO_PCI_NUM_IRQS;
 863         mutex_init(&vdev->igate);
 864         spin_lock_init(&vdev->irqlock);
 865
 866         ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
 867         if (ret) {
 868                 iommu_group_put(group);
 869                 kfree(vdev);
 870         }
 871
 872         return ret;
 873 }
 874
 875 static void vfio_pci_remove(struct pci_dev *pdev)
 876 {
 877         struct vfio_pci_device *vdev;
 878
 879         mutex_lock(&driver_lock);
 880
 881         vdev = vfio_del_group_dev(&pdev->dev);
 882         if (vdev) {
 883                 iommu_group_put(pdev->dev.iommu_group);
 884                 kfree(vdev);
 885         }
 886
 887         mutex_unlock(&driver_lock);
 888 }
 889
 890 static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
 891                                                   pci_channel_state_t state)
 892 {
 893         struct vfio_pci_device *vdev;
 894         struct vfio_device *device;
 895
 896         device = vfio_device_get_from_dev(&pdev->dev);
 897         if (device == NULL)
 898                 return PCI_ERS_RESULT_DISCONNECT;
 899
 900         vdev = vfio_device_data(device);
 901         if (vdev == NULL) {
 902                 vfio_device_put(device);
 903                 return PCI_ERS_RESULT_DISCONNECT;
 904         }
 905
 906         mutex_lock(&vdev->igate);
 907
 908         if (vdev->err_trigger)
 909                 eventfd_signal(vdev->err_trigger, 1);
 910
 911         mutex_unlock(&vdev->igate);
 912
 913         vfio_device_put(device);
 914
 915         return PCI_ERS_RESULT_CAN_RECOVER;
 916 }
 917
 918 static struct pci_error_handlers vfio_err_handlers = {
 919         .error_detected = vfio_pci_aer_err_detected,
 920 };
 921
 922 static struct pci_driver vfio_pci_driver = {
 923         .name           = "vfio-pci",
 924         .id_table       = NULL, /* only dynamic ids */
 925         .probe          = vfio_pci_probe,
 926         .remove         = vfio_pci_remove,
 927         .err_handler    = &vfio_err_handlers,
 928 };
 929
 930 /*
 931  * Test whether a reset is necessary and possible.  We mark devices as
 932  * needs_reset when they are released, but don't have a function-local reset
 933  * available.  If any of these exist in the affected devices, we want to do
 934  * a bus/slot reset.  We also need all of the affected devices to be unused,
 935  * so we abort if any device has a non-zero refcnt.  driver_lock prevents a
 936  * device from being opened during the scan or unbound from vfio-pci.
 937  */
 938 static int vfio_pci_test_bus_reset(struct pci_dev *pdev, void *data)
 939 {
 940         bool *needs_reset = data;
 941         struct pci_driver *pci_drv = ACCESS_ONCE(pdev->driver);
 942         int ret = -EBUSY;
 943
 944         if (pci_drv == &vfio_pci_driver) {
 945                 struct vfio_device *device;
 946                 struct vfio_pci_device *vdev;
 947
 948                 device = vfio_device_get_from_dev(&pdev->dev);
 949                 if (!device)
 950                         return ret;
 951
 952                 vdev = vfio_device_data(device);
 953                 if (vdev) {
 954                         if (vdev->needs_reset)
 955                                 *needs_reset = true;
 956
 957                         if (!vdev->refcnt)
 958                                 ret = 0;
 959                 }
 960
 961                 vfio_device_put(device);
 962         }
 963
 964         /*
 965          * TODO: vfio-core considers groups to be viable even if some devices
 966          * are attached to known drivers, like pci-stub or pcieport.  We can't
 967          * freeze devices from being unbound to those drivers like we can
 968          * here though, so it would be racy to test for them.  We also can't
 969          * use device_lock() to prevent changes as that would interfere with
 970          * PCI-core taking device_lock during bus reset.  For now, we require
 971          * devices to be bound to vfio-pci to get a bus/slot reset on release.
 972          */
 973
 974         return ret;
 975 }
 976
 977 /* Clear needs_reset on all affected devices after successful bus/slot reset */
 978 static int vfio_pci_clear_needs_reset(struct pci_dev *pdev, void *data)
 979 {
 980         struct pci_driver *pci_drv = ACCESS_ONCE(pdev->driver);
 981
 982         if (pci_drv == &vfio_pci_driver) {
 983                 struct vfio_device *device;
 984                 struct vfio_pci_device *vdev;
 985
 986                 device = vfio_device_get_from_dev(&pdev->dev);
 987                 if (!device)
 988                         return 0;
 989
 990                 vdev = vfio_device_data(device);
 991                 if (vdev)
 992                         vdev->needs_reset = false;
 993
 994                 vfio_device_put(device);
 995         }
 996
 997         return 0;
 998 }
 999
1000 /*
1001  * Attempt to do a bus/slot reset if there are devices affected by a reset for
1002  * this device that are needs_reset and all of the affected devices are unused
1003  * (!refcnt).  Callers of this function are required to hold driver_lock such
1004  * that devices can not be unbound from vfio-pci or opened by a user while we
1005  * test for and perform a bus/slot reset.
1006  */
1007 static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
1008 {
1009         bool needs_reset = false, slot = false;
1010         int ret;
1011
1012         if (!pci_probe_reset_slot(vdev->pdev->slot))
1013                 slot = true;
1014         else if (pci_probe_reset_bus(vdev->pdev->bus))
1015                 return;
1016
1017         if (vfio_pci_for_each_slot_or_bus(vdev->pdev,
1018                                           vfio_pci_test_bus_reset,
1019                                           &needs_reset, slot) || !needs_reset)
1020                 return;
1021
1022         if (slot)
1023                 ret = pci_try_reset_slot(vdev->pdev->slot);
1024         else
1025                 ret = pci_try_reset_bus(vdev->pdev->bus);
1026
1027         if (ret)
1028                 return;
1029
1030         vfio_pci_for_each_slot_or_bus(vdev->pdev,
1031                                       vfio_pci_clear_needs_reset, NULL, slot);
1032 }
1033
1034 static void __exit vfio_pci_cleanup(void)
1035 {
1036         pci_unregister_driver(&vfio_pci_driver);
1037         vfio_pci_virqfd_exit();
1038         vfio_pci_uninit_perm_bits();
1039 }
1040
1041 static int __init vfio_pci_init(void)
1042 {
1043         int ret;
1044
1045         /* Allocate shared config space permision data used by all devices */
1046         ret = vfio_pci_init_perm_bits();
1047         if (ret)
1048                 return ret;
1049
1050         /* Start the virqfd cleanup handler */
1051         ret = vfio_pci_virqfd_init();
1052         if (ret)
1053                 goto out_virqfd;
1054
1055         /* Register and scan for devices */
1056         ret = pci_register_driver(&vfio_pci_driver);
1057         if (ret)
1058                 goto out_driver;
1059
1060         return 0;
1061
1062 out_driver:
1063         vfio_pci_virqfd_exit();
1064 out_virqfd:
1065         vfio_pci_uninit_perm_bits();
1066         return ret;
1067 }
1068
1069 module_init(vfio_pci_init);
1070 module_exit(vfio_pci_cleanup);
1071
1072 MODULE_VERSION(DRIVER_VERSION);
1073 MODULE_LICENSE("GPL v2");
1074 MODULE_AUTHOR(DRIVER_AUTHOR);
1075 MODULE_DESCRIPTION(DRIVER_DESC);