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/interrupt.h>
  17 #include <linux/iommu.h>
  18 #include <linux/module.h>
  19 #include <linux/mutex.h>
  20 #include <linux/notifier.h>
  21 #include <linux/pci.h>
  22 #include <linux/pm_runtime.h>
  23 #include <linux/slab.h>
  24 #include <linux/types.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/vfio.h>
  27
  28 #include "vfio_pci_private.h"
  29
  30 #define DRIVER_VERSION  "0.2"
  31 #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
  32 #define DRIVER_DESC     "VFIO PCI - User Level meta-driver"
  33
  34 static bool nointxmask;
  35 module_param_named(nointxmask, nointxmask, bool, S_IRUGO | S_IWUSR);
  36 MODULE_PARM_DESC(nointxmask,
  37                   "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.");
  38
  39 static int vfio_pci_enable(struct vfio_pci_device *vdev)
  40 {
  41         struct pci_dev *pdev = vdev->pdev;
  42         int ret;
  43         u16 cmd;
  44         u8 msix_pos;
  45
  46         ret = pci_enable_device(pdev);
  47         if (ret)
  48                 return ret;
  49
  50         vdev->reset_works = (pci_reset_function(pdev) == 0);
  51         pci_save_state(pdev);
  52         vdev->pci_saved_state = pci_store_saved_state(pdev);
  53         if (!vdev->pci_saved_state)
  54                 pr_debug("%s: Couldn't store %s saved state\n",
  55                          __func__, dev_name(&pdev->dev));
  56
  57         ret = vfio_config_init(vdev);
  58         if (ret) {
  59                 pci_load_and_free_saved_state(pdev, &vdev->pci_saved_state);
  60                 pci_disable_device(pdev);
  61                 return ret;
  62         }
  63
  64         if (likely(!nointxmask))
  65                 vdev->pci_2_3 = pci_intx_mask_supported(pdev);
  66
  67         pci_read_config_word(pdev, PCI_COMMAND, &cmd);
  68         if (vdev->pci_2_3 && (cmd & PCI_COMMAND_INTX_DISABLE)) {
  69                 cmd &= ~PCI_COMMAND_INTX_DISABLE;
  70                 pci_write_config_word(pdev, PCI_COMMAND, cmd);
  71         }
  72
  73         msix_pos = pci_find_capability(pdev, PCI_CAP_ID_MSIX);
  74         if (msix_pos) {
  75                 u16 flags;
  76                 u32 table;
  77
  78                 pci_read_config_word(pdev, msix_pos + PCI_MSIX_FLAGS, &flags);
  79                 pci_read_config_dword(pdev, msix_pos + PCI_MSIX_TABLE, &table);
  80
  81                 vdev->msix_bar = table & PCI_MSIX_FLAGS_BIRMASK;
  82                 vdev->msix_offset = table & ~PCI_MSIX_FLAGS_BIRMASK;
  83                 vdev->msix_size = ((flags & PCI_MSIX_FLAGS_QSIZE) + 1) * 16;
  84         } else
  85                 vdev->msix_bar = 0xFF;
  86
  87 #ifdef CONFIG_VFIO_PCI_VGA
  88         if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
  89                 vdev->has_vga = true;
  90 #endif
  91
  92         return 0;
  93 }
  94
  95 static void vfio_pci_disable(struct vfio_pci_device *vdev)
  96 {
  97         struct pci_dev *pdev = vdev->pdev;
  98         int bar;
  99
 100         pci_disable_device(pdev);
 101
 102         vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE |
 103                                 VFIO_IRQ_SET_ACTION_TRIGGER,
 104                                 vdev->irq_type, 0, 0, NULL);
 105
 106         vdev->virq_disabled = false;
 107
 108         vfio_config_free(vdev);
 109
 110         for (bar = PCI_STD_RESOURCES; bar <= PCI_STD_RESOURCE_END; bar++) {
 111                 if (!vdev->barmap[bar])
 112                         continue;
 113                 pci_iounmap(pdev, vdev->barmap[bar]);
 114                 pci_release_selected_regions(pdev, 1 << bar);
 115                 vdev->barmap[bar] = NULL;
 116         }
 117
 118         /*
 119          * If we have saved state, restore it.  If we can reset the device,
 120          * even better.  Resetting with current state seems better than
 121          * nothing, but saving and restoring current state without reset
 122          * is just busy work.
 123          */
 124         if (pci_load_and_free_saved_state(pdev, &vdev->pci_saved_state)) {
 125                 pr_info("%s: Couldn't reload %s saved state\n",
 126                         __func__, dev_name(&pdev->dev));
 127
 128                 if (!vdev->reset_works)
 129                         return;
 130
 131                 pci_save_state(pdev);
 132         }
 133
 134         /*
 135          * Disable INTx and MSI, presumably to avoid spurious interrupts
 136          * during reset.  Stolen from pci_reset_function()
 137          */
 138         pci_write_config_word(pdev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
 139
 140         if (vdev->reset_works)
 141                 __pci_reset_function(pdev);
 142
 143         pci_restore_state(pdev);
 144 }
 145
 146 static void vfio_pci_release(void *device_data)
 147 {
 148         struct vfio_pci_device *vdev = device_data;
 149
 150         if (atomic_dec_and_test(&vdev->refcnt))
 151                 vfio_pci_disable(vdev);
 152
 153         module_put(THIS_MODULE);
 154 }
 155
 156 static int vfio_pci_open(void *device_data)
 157 {
 158         struct vfio_pci_device *vdev = device_data;
 159
 160         if (!try_module_get(THIS_MODULE))
 161                 return -ENODEV;
 162
 163         if (atomic_inc_return(&vdev->refcnt) == 1) {
 164                 int ret = vfio_pci_enable(vdev);
 165                 if (ret) {
 166                         module_put(THIS_MODULE);
 167                         return ret;
 168                 }
 169         }
 170
 171         return 0;
 172 }
 173
 174 static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)
 175 {
 176         if (irq_type == VFIO_PCI_INTX_IRQ_INDEX) {
 177                 u8 pin;
 178                 pci_read_config_byte(vdev->pdev, PCI_INTERRUPT_PIN, &pin);
 179                 if (pin)
 180                         return 1;
 181
 182         } else if (irq_type == VFIO_PCI_MSI_IRQ_INDEX) {
 183                 u8 pos;
 184                 u16 flags;
 185
 186                 pos = pci_find_capability(vdev->pdev, PCI_CAP_ID_MSI);
 187                 if (pos) {
 188                         pci_read_config_word(vdev->pdev,
 189                                              pos + PCI_MSI_FLAGS, &flags);
 190
 191                         return 1 << (flags & PCI_MSI_FLAGS_QMASK);
 192                 }
 193         } else if (irq_type == VFIO_PCI_MSIX_IRQ_INDEX) {
 194                 u8 pos;
 195                 u16 flags;
 196
 197                 pos = pci_find_capability(vdev->pdev, PCI_CAP_ID_MSIX);
 198                 if (pos) {
 199                         pci_read_config_word(vdev->pdev,
 200                                              pos + PCI_MSIX_FLAGS, &flags);
 201
 202                         return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
 203                 }
 204         }
 205
 206         return 0;
 207 }
 208
 209 static long vfio_pci_ioctl(void *device_data,
 210                            unsigned int cmd, unsigned long arg)
 211 {
 212         struct vfio_pci_device *vdev = device_data;
 213         unsigned long minsz;
 214
 215         if (cmd == VFIO_DEVICE_GET_INFO) {
 216                 struct vfio_device_info info;
 217
 218                 minsz = offsetofend(struct vfio_device_info, num_irqs);
 219
 220                 if (copy_from_user(&info, (void __user *)arg, minsz))
 221                         return -EFAULT;
 222
 223                 if (info.argsz < minsz)
 224                         return -EINVAL;
 225
 226                 info.flags = VFIO_DEVICE_FLAGS_PCI;
 227
 228                 if (vdev->reset_works)
 229                         info.flags |= VFIO_DEVICE_FLAGS_RESET;
 230
 231                 info.num_regions = VFIO_PCI_NUM_REGIONS;
 232                 info.num_irqs = VFIO_PCI_NUM_IRQS;
 233
 234                 return copy_to_user((void __user *)arg, &info, minsz);
 235
 236         } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
 237                 struct pci_dev *pdev = vdev->pdev;
 238                 struct vfio_region_info info;
 239
 240                 minsz = offsetofend(struct vfio_region_info, offset);
 241
 242                 if (copy_from_user(&info, (void __user *)arg, minsz))
 243                         return -EFAULT;
 244
 245                 if (info.argsz < minsz)
 246                         return -EINVAL;
 247
 248                 switch (info.index) {
 249                 case VFIO_PCI_CONFIG_REGION_INDEX:
 250                         info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
 251                         info.size = pdev->cfg_size;
 252                         info.flags = VFIO_REGION_INFO_FLAG_READ |
 253                                      VFIO_REGION_INFO_FLAG_WRITE;
 254                         break;
 255                 case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
 256                         info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
 257                         info.size = pci_resource_len(pdev, info.index);
 258                         if (!info.size) {
 259                                 info.flags = 0;
 260                                 break;
 261                         }
 262
 263                         info.flags = VFIO_REGION_INFO_FLAG_READ |
 264                                      VFIO_REGION_INFO_FLAG_WRITE;
 265                         if (pci_resource_flags(pdev, info.index) &
 266                             IORESOURCE_MEM && info.size >= PAGE_SIZE)
 267                                 info.flags |= VFIO_REGION_INFO_FLAG_MMAP;
 268                         break;
 269                 case VFIO_PCI_ROM_REGION_INDEX:
 270                 {
 271                         void __iomem *io;
 272                         size_t size;
 273
 274                         info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
 275                         info.flags = 0;
 276
 277                         /* Report the BAR size, not the ROM size */
 278                         info.size = pci_resource_len(pdev, info.index);
 279                         if (!info.size)
 280                                 break;
 281
 282                         /* Is it really there? */
 283                         io = pci_map_rom(pdev, &size);
 284                         if (!io || !size) {
 285                                 info.size = 0;
 286                                 break;
 287                         }
 288                         pci_unmap_rom(pdev, io);
 289
 290                         info.flags = VFIO_REGION_INFO_FLAG_READ;
 291                         break;
 292                 }
 293                 case VFIO_PCI_VGA_REGION_INDEX:
 294                         if (!vdev->has_vga)
 295                                 return -EINVAL;
 296
 297                         info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
 298                         info.size = 0xc0000;
 299                         info.flags = VFIO_REGION_INFO_FLAG_READ |
 300                                      VFIO_REGION_INFO_FLAG_WRITE;
 301
 302                         break;
 303                 default:
 304                         return -EINVAL;
 305                 }
 306
 307                 return copy_to_user((void __user *)arg, &info, minsz);
 308
 309         } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
 310                 struct vfio_irq_info info;
 311
 312                 minsz = offsetofend(struct vfio_irq_info, count);
 313
 314                 if (copy_from_user(&info, (void __user *)arg, minsz))
 315                         return -EFAULT;
 316
 317                 if (info.argsz < minsz || info.index >= VFIO_PCI_NUM_IRQS)
 318                         return -EINVAL;
 319
 320                 info.flags = VFIO_IRQ_INFO_EVENTFD;
 321
 322                 info.count = vfio_pci_get_irq_count(vdev, info.index);
 323
 324                 if (info.index == VFIO_PCI_INTX_IRQ_INDEX)
 325                         info.flags |= (VFIO_IRQ_INFO_MASKABLE |
 326                                        VFIO_IRQ_INFO_AUTOMASKED);
 327                 else
 328                         info.flags |= VFIO_IRQ_INFO_NORESIZE;
 329
 330                 return copy_to_user((void __user *)arg, &info, minsz);
 331
 332         } else if (cmd == VFIO_DEVICE_SET_IRQS) {
 333                 struct vfio_irq_set hdr;
 334                 u8 *data = NULL;
 335                 int ret = 0;
 336
 337                 minsz = offsetofend(struct vfio_irq_set, count);
 338
 339                 if (copy_from_user(&hdr, (void __user *)arg, minsz))
 340                         return -EFAULT;
 341
 342                 if (hdr.argsz < minsz || hdr.index >= VFIO_PCI_NUM_IRQS ||
 343                     hdr.flags & ~(VFIO_IRQ_SET_DATA_TYPE_MASK |
 344                                   VFIO_IRQ_SET_ACTION_TYPE_MASK))
 345                         return -EINVAL;
 346
 347                 if (!(hdr.flags & VFIO_IRQ_SET_DATA_NONE)) {
 348                         size_t size;
 349                         int max = vfio_pci_get_irq_count(vdev, hdr.index);
 350
 351                         if (hdr.flags & VFIO_IRQ_SET_DATA_BOOL)
 352                                 size = sizeof(uint8_t);
 353                         else if (hdr.flags & VFIO_IRQ_SET_DATA_EVENTFD)
 354                                 size = sizeof(int32_t);
 355                         else
 356                                 return -EINVAL;
 357
 358                         if (hdr.argsz - minsz < hdr.count * size ||
 359                             hdr.start >= max || hdr.start + hdr.count > max)
 360                                 return -EINVAL;
 361
 362                         data = memdup_user((void __user *)(arg + minsz),
 363                                            hdr.count * size);
 364                         if (IS_ERR(data))
 365                                 return PTR_ERR(data);
 366                 }
 367
 368                 mutex_lock(&vdev->igate);
 369
 370                 ret = vfio_pci_set_irqs_ioctl(vdev, hdr.flags, hdr.index,
 371                                               hdr.start, hdr.count, data);
 372
 373                 mutex_unlock(&vdev->igate);
 374                 kfree(data);
 375
 376                 return ret;
 377
 378         } else if (cmd == VFIO_DEVICE_RESET)
 379                 return vdev->reset_works ?
 380                         pci_reset_function(vdev->pdev) : -EINVAL;
 381
 382         return -ENOTTY;
 383 }
 384
 385 static ssize_t vfio_pci_rw(void *device_data, char __user *buf,
 386                            size_t count, loff_t *ppos, bool iswrite)
 387 {
 388         unsigned int index = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
 389         struct vfio_pci_device *vdev = device_data;
 390
 391         if (index >= VFIO_PCI_NUM_REGIONS)
 392                 return -EINVAL;
 393
 394         switch (index) {
 395         case VFIO_PCI_CONFIG_REGION_INDEX:
 396                 return vfio_pci_config_rw(vdev, buf, count, ppos, iswrite);
 397
 398         case VFIO_PCI_ROM_REGION_INDEX:
 399                 if (iswrite)
 400                         return -EINVAL;
 401                 return vfio_pci_bar_rw(vdev, buf, count, ppos, false);
 402
 403         case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
 404                 return vfio_pci_bar_rw(vdev, buf, count, ppos, iswrite);
 405
 406         case VFIO_PCI_VGA_REGION_INDEX:
 407                 return vfio_pci_vga_rw(vdev, buf, count, ppos, iswrite);
 408         }
 409
 410         return -EINVAL;
 411 }
 412
 413 static ssize_t vfio_pci_read(void *device_data, char __user *buf,
 414                              size_t count, loff_t *ppos)
 415 {
 416         if (!count)
 417                 return 0;
 418
 419         return vfio_pci_rw(device_data, buf, count, ppos, false);
 420 }
 421
 422 static ssize_t vfio_pci_write(void *device_data, const char __user *buf,
 423                               size_t count, loff_t *ppos)
 424 {
 425         if (!count)
 426                 return 0;
 427
 428         return vfio_pci_rw(device_data, (char __user *)buf, count, ppos, true);
 429 }
 430
 431 static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma)
 432 {
 433         struct vfio_pci_device *vdev = device_data;
 434         struct pci_dev *pdev = vdev->pdev;
 435         unsigned int index;
 436         u64 phys_len, req_len, pgoff, req_start;
 437         int ret;
 438
 439         index = vma->vm_pgoff >> (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT);
 440
 441         if (vma->vm_end < vma->vm_start)
 442                 return -EINVAL;
 443         if ((vma->vm_flags & VM_SHARED) == 0)
 444                 return -EINVAL;
 445         if (index >= VFIO_PCI_ROM_REGION_INDEX)
 446                 return -EINVAL;
 447         if (!(pci_resource_flags(pdev, index) & IORESOURCE_MEM))
 448                 return -EINVAL;
 449
 450         phys_len = pci_resource_len(pdev, index);
 451         req_len = vma->vm_end - vma->vm_start;
 452         pgoff = vma->vm_pgoff &
 453                 ((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
 454         req_start = pgoff << PAGE_SHIFT;
 455
 456         if (phys_len < PAGE_SIZE || req_start + req_len > phys_len)
 457                 return -EINVAL;
 458
 459         if (index == vdev->msix_bar) {
 460                 /*
 461                  * Disallow mmaps overlapping the MSI-X table; users don't
 462                  * get to touch this directly.  We could find somewhere
 463                  * else to map the overlap, but page granularity is only
 464                  * a recommendation, not a requirement, so the user needs
 465                  * to know which bits are real.  Requiring them to mmap
 466                  * around the table makes that clear.
 467                  */
 468
 469                 /* If neither entirely above nor below, then it overlaps */
 470                 if (!(req_start >= vdev->msix_offset + vdev->msix_size ||
 471                       req_start + req_len <= vdev->msix_offset))
 472                         return -EINVAL;
 473         }
 474
 475         /*
 476          * Even though we don't make use of the barmap for the mmap,
 477          * we need to request the region and the barmap tracks that.
 478          */
 479         if (!vdev->barmap[index]) {
 480                 ret = pci_request_selected_regions(pdev,
 481                                                    1 << index, "vfio-pci");
 482                 if (ret)
 483                         return ret;
 484
 485                 vdev->barmap[index] = pci_iomap(pdev, index, 0);
 486         }
 487
 488         vma->vm_private_data = vdev;
 489         vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
 490         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 491         vma->vm_pgoff = (pci_resource_start(pdev, index) >> PAGE_SHIFT) + pgoff;
 492
 493         return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
 494                                req_len, vma->vm_page_prot);
 495 }
 496
 497 static const struct vfio_device_ops vfio_pci_ops = {
 498         .name           = "vfio-pci",
 499         .open           = vfio_pci_open,
 500         .release        = vfio_pci_release,
 501         .ioctl          = vfio_pci_ioctl,
 502         .read           = vfio_pci_read,
 503         .write          = vfio_pci_write,
 504         .mmap           = vfio_pci_mmap,
 505 };
 506
 507 static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 508 {
 509         u8 type;
 510         struct vfio_pci_device *vdev;
 511         struct iommu_group *group;
 512         int ret;
 513
 514         pci_read_config_byte(pdev, PCI_HEADER_TYPE, &type);
 515         if ((type & PCI_HEADER_TYPE) != PCI_HEADER_TYPE_NORMAL)
 516                 return -EINVAL;
 517
 518         group = iommu_group_get(&pdev->dev);
 519         if (!group)
 520                 return -EINVAL;
 521
 522         vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 523         if (!vdev) {
 524                 iommu_group_put(group);
 525                 return -ENOMEM;
 526         }
 527
 528         vdev->pdev = pdev;
 529         vdev->irq_type = VFIO_PCI_NUM_IRQS;
 530         mutex_init(&vdev->igate);
 531         spin_lock_init(&vdev->irqlock);
 532         atomic_set(&vdev->refcnt, 0);
 533
 534         ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
 535         if (ret) {
 536                 iommu_group_put(group);
 537                 kfree(vdev);
 538         }
 539
 540         return ret;
 541 }
 542
 543 static void vfio_pci_remove(struct pci_dev *pdev)
 544 {
 545         struct vfio_pci_device *vdev;
 546
 547         vdev = vfio_del_group_dev(&pdev->dev);
 548         if (!vdev)
 549                 return;
 550
 551         iommu_group_put(pdev->dev.iommu_group);
 552         kfree(vdev);
 553 }
 554
 555 static struct pci_driver vfio_pci_driver = {
 556         .name           = "vfio-pci",
 557         .id_table       = NULL, /* only dynamic ids */
 558         .probe          = vfio_pci_probe,
 559         .remove         = vfio_pci_remove,
 560 };
 561
 562 static void __exit vfio_pci_cleanup(void)
 563 {
 564         pci_unregister_driver(&vfio_pci_driver);
 565         vfio_pci_virqfd_exit();
 566         vfio_pci_uninit_perm_bits();
 567 }
 568
 569 static int __init vfio_pci_init(void)
 570 {
 571         int ret;
 572
 573         /* Allocate shared config space permision data used by all devices */
 574         ret = vfio_pci_init_perm_bits();
 575         if (ret)
 576                 return ret;
 577
 578         /* Start the virqfd cleanup handler */
 579         ret = vfio_pci_virqfd_init();
 580         if (ret)
 581                 goto out_virqfd;
 582
 583         /* Register and scan for devices */
 584         ret = pci_register_driver(&vfio_pci_driver);
 585         if (ret)
 586                 goto out_driver;
 587
 588         return 0;
 589
 590 out_driver:
 591         vfio_pci_virqfd_exit();
 592 out_virqfd:
 593         vfio_pci_uninit_perm_bits();
 594         return ret;
 595 }
 596
 597 module_init(vfio_pci_init);
 598 module_exit(vfio_pci_cleanup);
 599
 600 MODULE_VERSION(DRIVER_VERSION);
 601 MODULE_LICENSE("GPL v2");
 602 MODULE_AUTHOR(DRIVER_AUTHOR);
 603 MODULE_DESCRIPTION(DRIVER_DESC);