drivers/virtio/virtio_pci_modern.c

   1 /*
   2  * Virtio PCI driver - modern (virtio 1.0) device support
   3  *
   4  * This module allows virtio devices to be used over a virtual PCI device.
   5  * This can be used with QEMU based VMMs like KVM or Xen.
   6  *
   7  * Copyright IBM Corp. 2007
   8  * Copyright Red Hat, Inc. 2014
   9  *
  10  * Authors:
  11  *  Anthony Liguori  <aliguori@us.ibm.com>
  12  *  Rusty Russell <rusty@rustcorp.com.au>
  13  *  Michael S. Tsirkin <mst@redhat.com>
  14  *
  15  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  16  * See the COPYING file in the top-level directory.
  17  *
  18  */
  19
  20 #define VIRTIO_PCI_NO_LEGACY
  21 #include "virtio_pci_common.h"
  22
  23 static void __iomem *map_capability(struct pci_dev *dev, int off,
  24                                     size_t minlen,
  25                                     u32 align,
  26                                     u32 start, u32 size,
  27                                     size_t *len)
  28 {
  29         u8 bar;
  30         u32 offset, length;
  31         void __iomem *p;
  32
  33         pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
  34                                                  bar),
  35                              &bar);
  36         pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
  37                              &offset);
  38         pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
  39                               &length);
  40
  41         if (length <= start) {
  42                 dev_err(&dev->dev,
  43                         "virtio_pci: bad capability len %u (>%u expected)\n",
  44                         length, start);
  45                 return NULL;
  46         }
  47
  48         if (length - start < minlen) {
  49                 dev_err(&dev->dev,
  50                         "virtio_pci: bad capability len %u (>=%zu expected)\n",
  51                         length, minlen);
  52                 return NULL;
  53         }
  54
  55         length -= start;
  56
  57         if (start + offset < offset) {
  58                 dev_err(&dev->dev,
  59                         "virtio_pci: map wrap-around %u+%u\n",
  60                         start, offset);
  61                 return NULL;
  62         }
  63
  64         offset += start;
  65
  66         if (offset & (align - 1)) {
  67                 dev_err(&dev->dev,
  68                         "virtio_pci: offset %u not aligned to %u\n",
  69                         offset, align);
  70                 return NULL;
  71         }
  72
  73         if (length > size)
  74                 length = size;
  75
  76         if (len)
  77                 *len = length;
  78
  79         if (minlen + offset < minlen ||
  80             minlen + offset > pci_resource_len(dev, bar)) {
  81                 dev_err(&dev->dev,
  82                         "virtio_pci: map virtio %zu@%u "
  83                         "out of range on bar %i length %lu\n",
  84                         minlen, offset,
  85                         bar, (unsigned long)pci_resource_len(dev, bar));
  86                 return NULL;
  87         }
  88
  89         p = pci_iomap_range(dev, bar, offset, length);
  90         if (!p)
  91                 dev_err(&dev->dev,
  92                         "virtio_pci: unable to map virtio %u@%u on bar %i\n",
  93                         length, offset, bar);
  94         return p;
  95 }
  96
  97 static void iowrite64_twopart(u64 val, __le32 __iomem *lo, __le32 __iomem *hi)
  98 {
  99         iowrite32((u32)val, lo);
 100         iowrite32(val >> 32, hi);
 101 }
 102
 103 /* virtio config->get_features() implementation */
 104 static u64 vp_get_features(struct virtio_device *vdev)
 105 {
 106         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 107         u64 features;
 108
 109         iowrite32(0, &vp_dev->common->device_feature_select);
 110         features = ioread32(&vp_dev->common->device_feature);
 111         iowrite32(1, &vp_dev->common->device_feature_select);
 112         features |= ((u64)ioread32(&vp_dev->common->device_feature) << 32);
 113
 114         return features;
 115 }
 116
 117 /* virtio config->finalize_features() implementation */
 118 static int vp_finalize_features(struct virtio_device *vdev)
 119 {
 120         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 121
 122         /* Give virtio_ring a chance to accept features. */
 123         vring_transport_features(vdev);
 124
 125         if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
 126                 dev_err(&vdev->dev, "virtio: device uses modern interface "
 127                         "but does not have VIRTIO_F_VERSION_1\n");
 128                 return -EINVAL;
 129         }
 130
 131         iowrite32(0, &vp_dev->common->guest_feature_select);
 132         iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);
 133         iowrite32(1, &vp_dev->common->guest_feature_select);
 134         iowrite32(vdev->features >> 32, &vp_dev->common->guest_feature);
 135
 136         return 0;
 137 }
 138
 139 /* virtio config->get() implementation */
 140 static void vp_get(struct virtio_device *vdev, unsigned offset,
 141                    void *buf, unsigned len)
 142 {
 143         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 144         u8 b;
 145         __le16 w;
 146         __le32 l;
 147
 148         BUG_ON(offset + len > vp_dev->device_len);
 149
 150         switch (len) {
 151         case 1:
 152                 b = ioread8(vp_dev->device + offset);
 153                 memcpy(buf, &b, sizeof b);
 154                 break;
 155         case 2:
 156                 w = cpu_to_le16(ioread16(vp_dev->device + offset));
 157                 memcpy(buf, &w, sizeof w);
 158                 break;
 159         case 4:
 160                 l = cpu_to_le32(ioread32(vp_dev->device + offset));
 161                 memcpy(buf, &l, sizeof l);
 162                 break;
 163         case 8:
 164                 l = cpu_to_le32(ioread32(vp_dev->device + offset));
 165                 memcpy(buf, &l, sizeof l);
 166                 l = cpu_to_le32(ioread32(vp_dev->device + offset + sizeof l));
 167                 memcpy(buf + sizeof l, &l, sizeof l);
 168                 break;
 169         default:
 170                 BUG();
 171         }
 172 }
 173
 174 /* the config->set() implementation.  it's symmetric to the config->get()
 175  * implementation */
 176 static void vp_set(struct virtio_device *vdev, unsigned offset,
 177                    const void *buf, unsigned len)
 178 {
 179         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 180         u8 b;
 181         __le16 w;
 182         __le32 l;
 183
 184         BUG_ON(offset + len > vp_dev->device_len);
 185
 186         switch (len) {
 187         case 1:
 188                 memcpy(&b, buf, sizeof b);
 189                 iowrite8(b, vp_dev->device + offset);
 190                 break;
 191         case 2:
 192                 memcpy(&w, buf, sizeof w);
 193                 iowrite16(le16_to_cpu(w), vp_dev->device + offset);
 194                 break;
 195         case 4:
 196                 memcpy(&l, buf, sizeof l);
 197                 iowrite32(le32_to_cpu(l), vp_dev->device + offset);
 198                 break;
 199         case 8:
 200                 memcpy(&l, buf, sizeof l);
 201                 iowrite32(le32_to_cpu(l), vp_dev->device + offset);
 202                 memcpy(&l, buf + sizeof l, sizeof l);
 203                 iowrite32(le32_to_cpu(l), vp_dev->device + offset + sizeof l);
 204                 break;
 205         default:
 206                 BUG();
 207         }
 208 }
 209
 210 static u32 vp_generation(struct virtio_device *vdev)
 211 {
 212         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 213         return ioread8(&vp_dev->common->config_generation);
 214 }
 215
 216 /* config->{get,set}_status() implementations */
 217 static u8 vp_get_status(struct virtio_device *vdev)
 218 {
 219         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 220         return ioread8(&vp_dev->common->device_status);
 221 }
 222
 223 static void vp_set_status(struct virtio_device *vdev, u8 status)
 224 {
 225         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 226         /* We should never be setting status to 0. */
 227         BUG_ON(status == 0);
 228         iowrite8(status, &vp_dev->common->device_status);
 229 }
 230
 231 static void vp_reset(struct virtio_device *vdev)
 232 {
 233         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 234         /* 0 status means a reset. */
 235         iowrite8(0, &vp_dev->common->device_status);
 236         /* Flush out the status write, and flush in device writes,
 237          * including MSI-X interrupts, if any. */
 238         ioread8(&vp_dev->common->device_status);
 239         /* Flush pending VQ/configuration callbacks. */
 240         vp_synchronize_vectors(vdev);
 241 }
 242
 243 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
 244 {
 245         /* Setup the vector used for configuration events */
 246         iowrite16(vector, &vp_dev->common->msix_config);
 247         /* Verify we had enough resources to assign the vector */
 248         /* Will also flush the write out to device */
 249         return ioread16(&vp_dev->common->msix_config);
 250 }
 251
 252 static size_t vring_pci_size(u16 num)
 253 {
 254         /* We only need a cacheline separation. */
 255         return PAGE_ALIGN(vring_size(num, SMP_CACHE_BYTES));
 256 }
 257
 258 static void *alloc_virtqueue_pages(int *num)
 259 {
 260         void *pages;
 261
 262         /* TODO: allocate each queue chunk individually */
 263         for (; *num && vring_pci_size(*num) > PAGE_SIZE; *num /= 2) {
 264                 pages = alloc_pages_exact(vring_pci_size(*num),
 265                                           GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);
 266                 if (pages)
 267                         return pages;
 268         }
 269
 270         if (!*num)
 271                 return NULL;
 272
 273         /* Try to get a single page. You are my only hope! */
 274         return alloc_pages_exact(vring_pci_size(*num), GFP_KERNEL|__GFP_ZERO);
 275 }
 276
 277 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 278                                   struct virtio_pci_vq_info *info,
 279                                   unsigned index,
 280                                   void (*callback)(struct virtqueue *vq),
 281                                   const char *name,
 282                                   u16 msix_vec)
 283 {
 284         struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
 285         struct virtqueue *vq;
 286         u16 num, off;
 287         int err;
 288
 289         if (index >= ioread16(&cfg->num_queues))
 290                 return ERR_PTR(-ENOENT);
 291
 292         /* Select the queue we're interested in */
 293         iowrite16(index, &cfg->queue_select);
 294
 295         /* Check if queue is either not available or already active. */
 296         num = ioread16(&cfg->queue_size);
 297         if (!num || ioread16(&cfg->queue_enable))
 298                 return ERR_PTR(-ENOENT);
 299
 300         if (num & (num - 1)) {
 301                 dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);
 302                 return ERR_PTR(-EINVAL);
 303         }
 304
 305         /* get offset of notification word for this vq */
 306         off = ioread16(&cfg->queue_notify_off);
 307
 308         info->num = num;
 309         info->msix_vector = msix_vec;
 310
 311         info->queue = alloc_virtqueue_pages(&info->num);
 312         if (info->queue == NULL)
 313                 return ERR_PTR(-ENOMEM);
 314
 315         /* create the vring */
 316         vq = vring_new_virtqueue(index, info->num,
 317                                  SMP_CACHE_BYTES, &vp_dev->vdev,
 318                                  true, info->queue, vp_notify, callback, name);
 319         if (!vq) {
 320                 err = -ENOMEM;
 321                 goto err_new_queue;
 322         }
 323
 324         /* activate the queue */
 325         iowrite16(num, &cfg->queue_size);
 326         iowrite64_twopart(virt_to_phys(info->queue),
 327                           &cfg->queue_desc_lo, &cfg->queue_desc_hi);
 328         iowrite64_twopart(virt_to_phys(virtqueue_get_avail(vq)),
 329                           &cfg->queue_avail_lo, &cfg->queue_avail_hi);
 330         iowrite64_twopart(virt_to_phys(virtqueue_get_used(vq)),
 331                           &cfg->queue_used_lo, &cfg->queue_used_hi);
 332
 333         if (vp_dev->notify_base) {
 334                 /* offset should not wrap */
 335                 if ((u64)off * vp_dev->notify_offset_multiplier + 2
 336                     > vp_dev->notify_len) {
 337                         dev_warn(&vp_dev->pci_dev->dev,
 338                                  "bad notification offset %u (x %u) "
 339                                  "for queue %u > %zd",
 340                                  off, vp_dev->notify_offset_multiplier,
 341                                  index, vp_dev->notify_len);
 342                         err = -EINVAL;
 343                         goto err_map_notify;
 344                 }
 345                 vq->priv = (void __force *)vp_dev->notify_base +
 346                         off * vp_dev->notify_offset_multiplier;
 347         } else {
 348                 vq->priv = (void __force *)map_capability(vp_dev->pci_dev,
 349                                           vp_dev->notify_map_cap, 2, 2,
 350                                           off * vp_dev->notify_offset_multiplier, 2,
 351                                           NULL);
 352         }
 353
 354         if (!vq->priv) {
 355                 err = -ENOMEM;
 356                 goto err_map_notify;
 357         }
 358
 359         if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
 360                 iowrite16(msix_vec, &cfg->queue_msix_vector);
 361                 msix_vec = ioread16(&cfg->queue_msix_vector);
 362                 if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
 363                         err = -EBUSY;
 364                         goto err_assign_vector;
 365                 }
 366         }
 367
 368         return vq;
 369
 370 err_assign_vector:
 371         if (!vp_dev->notify_base)
 372                 pci_iounmap(vp_dev->pci_dev, (void __iomem __force *)vq->priv);
 373 err_map_notify:
 374         vring_del_virtqueue(vq);
 375 err_new_queue:
 376         free_pages_exact(info->queue, vring_pci_size(info->num));
 377         return ERR_PTR(err);
 378 }
 379
 380 static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 381                               struct virtqueue *vqs[],
 382                               vq_callback_t *callbacks[],
 383                               const char *names[])
 384 {
 385         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 386         struct virtqueue *vq;
 387         int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names);
 388
 389         if (rc)
 390                 return rc;
 391
 392         /* Select and activate all queues. Has to be done last: once we do
 393          * this, there's no way to go back except reset.
 394          */
 395         list_for_each_entry(vq, &vdev->vqs, list) {
 396                 iowrite16(vq->index, &vp_dev->common->queue_select);
 397                 iowrite16(1, &vp_dev->common->queue_enable);
 398         }
 399
 400         return 0;
 401 }
 402
 403 static void del_vq(struct virtio_pci_vq_info *info)
 404 {
 405         struct virtqueue *vq = info->vq;
 406         struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 407
 408         iowrite16(vq->index, &vp_dev->common->queue_select);
 409
 410         if (vp_dev->msix_enabled) {
 411                 iowrite16(VIRTIO_MSI_NO_VECTOR,
 412                           &vp_dev->common->queue_msix_vector);
 413                 /* Flush the write out to device */
 414                 ioread16(&vp_dev->common->queue_msix_vector);
 415         }
 416
 417         if (!vp_dev->notify_base)
 418                 pci_iounmap(vp_dev->pci_dev, (void __force __iomem *)vq->priv);
 419
 420         vring_del_virtqueue(vq);
 421
 422         free_pages_exact(info->queue, vring_pci_size(info->num));
 423 }
 424
 425 static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
 426         .get            = NULL,
 427         .set            = NULL,
 428         .generation     = vp_generation,
 429         .get_status     = vp_get_status,
 430         .set_status     = vp_set_status,
 431         .reset          = vp_reset,
 432         .find_vqs       = vp_modern_find_vqs,
 433         .del_vqs        = vp_del_vqs,
 434         .get_features   = vp_get_features,
 435         .finalize_features = vp_finalize_features,
 436         .bus_name       = vp_bus_name,
 437         .set_vq_affinity = vp_set_vq_affinity,
 438 };
 439
 440 static const struct virtio_config_ops virtio_pci_config_ops = {
 441         .get            = vp_get,
 442         .set            = vp_set,
 443         .generation     = vp_generation,
 444         .get_status     = vp_get_status,
 445         .set_status     = vp_set_status,
 446         .reset          = vp_reset,
 447         .find_vqs       = vp_modern_find_vqs,
 448         .del_vqs        = vp_del_vqs,
 449         .get_features   = vp_get_features,
 450         .finalize_features = vp_finalize_features,
 451         .bus_name       = vp_bus_name,
 452         .set_vq_affinity = vp_set_vq_affinity,
 453 };
 454
 455 /**
 456  * virtio_pci_find_capability - walk capabilities to find device info.
 457  * @dev: the pci device
 458  * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
 459  * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
 460  *
 461  * Returns offset of the capability, or 0.
 462  */
 463 static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
 464                                              u32 ioresource_types)
 465 {
 466         int pos;
 467
 468         for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
 469              pos > 0;
 470              pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
 471                 u8 type, bar;
 472                 pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
 473                                                          cfg_type),
 474                                      &type);
 475                 pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
 476                                                          bar),
 477                                      &bar);
 478
 479                 /* Ignore structures with reserved BAR values */
 480                 if (bar > 0x5)
 481                         continue;
 482
 483                 if (type == cfg_type) {
 484                         if (pci_resource_len(dev, bar) &&
 485                             pci_resource_flags(dev, bar) & ioresource_types)
 486                                 return pos;
 487                 }
 488         }
 489         return 0;
 490 }
 491
 492 /* This is part of the ABI.  Don't screw with it. */
 493 static inline void check_offsets(void)
 494 {
 495         /* Note: disk space was harmed in compilation of this function. */
 496         BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
 497                      offsetof(struct virtio_pci_cap, cap_vndr));
 498         BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
 499                      offsetof(struct virtio_pci_cap, cap_next));
 500         BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
 501                      offsetof(struct virtio_pci_cap, cap_len));
 502         BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
 503                      offsetof(struct virtio_pci_cap, cfg_type));
 504         BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
 505                      offsetof(struct virtio_pci_cap, bar));
 506         BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
 507                      offsetof(struct virtio_pci_cap, offset));
 508         BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
 509                      offsetof(struct virtio_pci_cap, length));
 510         BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
 511                      offsetof(struct virtio_pci_notify_cap,
 512                               notify_off_multiplier));
 513         BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
 514                      offsetof(struct virtio_pci_common_cfg,
 515                               device_feature_select));
 516         BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
 517                      offsetof(struct virtio_pci_common_cfg, device_feature));
 518         BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
 519                      offsetof(struct virtio_pci_common_cfg,
 520                               guest_feature_select));
 521         BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
 522                      offsetof(struct virtio_pci_common_cfg, guest_feature));
 523         BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
 524                      offsetof(struct virtio_pci_common_cfg, msix_config));
 525         BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
 526                      offsetof(struct virtio_pci_common_cfg, num_queues));
 527         BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
 528                      offsetof(struct virtio_pci_common_cfg, device_status));
 529         BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
 530                      offsetof(struct virtio_pci_common_cfg, config_generation));
 531         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
 532                      offsetof(struct virtio_pci_common_cfg, queue_select));
 533         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
 534                      offsetof(struct virtio_pci_common_cfg, queue_size));
 535         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
 536                      offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
 537         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
 538                      offsetof(struct virtio_pci_common_cfg, queue_enable));
 539         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
 540                      offsetof(struct virtio_pci_common_cfg, queue_notify_off));
 541         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
 542                      offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
 543         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
 544                      offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
 545         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
 546                      offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
 547         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
 548                      offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
 549         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
 550                      offsetof(struct virtio_pci_common_cfg, queue_used_lo));
 551         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
 552                      offsetof(struct virtio_pci_common_cfg, queue_used_hi));
 553 }
 554
 555 /* the PCI probing function */
 556 int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
 557 {
 558         struct pci_dev *pci_dev = vp_dev->pci_dev;
 559         int err, common, isr, notify, device;
 560         u32 notify_length;
 561         u32 notify_offset;
 562
 563         check_offsets();
 564
 565         /* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
 566         if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
 567                 return -ENODEV;
 568
 569         if (pci_dev->device < 0x1040) {
 570                 /* Transitional devices: use the PCI subsystem device id as
 571                  * virtio device id, same as legacy driver always did.
 572                  */
 573                 vp_dev->vdev.id.device = pci_dev->subsystem_device;
 574         } else {
 575                 /* Modern devices: simply use PCI device id, but start from 0x1040. */
 576                 vp_dev->vdev.id.device = pci_dev->device - 0x1040;
 577         }
 578         vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
 579
 580         if (virtio_device_is_legacy_only(vp_dev->vdev.id))
 581                 return -ENODEV;
 582
 583         /* check for a common config: if not, use legacy mode (bar 0). */
 584         common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
 585                                             IORESOURCE_IO | IORESOURCE_MEM);
 586         if (!common) {
 587                 dev_info(&pci_dev->dev,
 588                          "virtio_pci: leaving for legacy driver\n");
 589                 return -ENODEV;
 590         }
 591
 592         /* If common is there, these should be too... */
 593         isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
 594                                          IORESOURCE_IO | IORESOURCE_MEM);
 595         notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
 596                                             IORESOURCE_IO | IORESOURCE_MEM);
 597         if (!isr || !notify) {
 598                 dev_err(&pci_dev->dev,
 599                         "virtio_pci: missing capabilities %i/%i/%i\n",
 600                         common, isr, notify);
 601                 return -EINVAL;
 602         }
 603
 604         /* Device capability is only mandatory for devices that have
 605          * device-specific configuration.
 606          */
 607         device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
 608                                             IORESOURCE_IO | IORESOURCE_MEM);
 609
 610         err = -EINVAL;
 611         vp_dev->common = map_capability(pci_dev, common,
 612                                         sizeof(struct virtio_pci_common_cfg), 4,
 613                                         0, sizeof(struct virtio_pci_common_cfg),
 614                                         NULL);
 615         if (!vp_dev->common)
 616                 goto err_map_common;
 617         vp_dev->isr = map_capability(pci_dev, isr, sizeof(u8), 1,
 618                                      0, 1,
 619                                      NULL);
 620         if (!vp_dev->isr)
 621                 goto err_map_isr;
 622
 623         /* Read notify_off_multiplier from config space. */
 624         pci_read_config_dword(pci_dev,
 625                               notify + offsetof(struct virtio_pci_notify_cap,
 626                                                 notify_off_multiplier),
 627                               &vp_dev->notify_offset_multiplier);
 628         /* Read notify length and offset from config space. */
 629         pci_read_config_dword(pci_dev,
 630                               notify + offsetof(struct virtio_pci_notify_cap,
 631                                                 cap.length),
 632                               &notify_length);
 633
 634         pci_read_config_dword(pci_dev,
 635                               notify + offsetof(struct virtio_pci_notify_cap,
 636                                                 cap.length),
 637                               &notify_offset);
 638
 639         /* We don't know how many VQs we'll map, ahead of the time.
 640          * If notify length is small, map it all now.
 641          * Otherwise, map each VQ individually later.
 642          */
 643         if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
 644                 vp_dev->notify_base = map_capability(pci_dev, notify, 2, 2,
 645                                                      0, notify_length,
 646                                                      &vp_dev->notify_len);
 647                 if (!vp_dev->notify_base)
 648                         goto err_map_notify;
 649         } else {
 650                 vp_dev->notify_map_cap = notify;
 651         }
 652
 653         /* Again, we don't know how much we should map, but PAGE_SIZE
 654          * is more than enough for all existing devices.
 655          */
 656         if (device) {
 657                 vp_dev->device = map_capability(pci_dev, device, 0, 4,
 658                                                 0, PAGE_SIZE,
 659                                                 &vp_dev->device_len);
 660                 if (!vp_dev->device)
 661                         goto err_map_device;
 662
 663                 vp_dev->vdev.config = &virtio_pci_config_ops;
 664         } else {
 665                 vp_dev->vdev.config = &virtio_pci_config_nodev_ops;
 666         }
 667
 668         vp_dev->config_vector = vp_config_vector;
 669         vp_dev->setup_vq = setup_vq;
 670         vp_dev->del_vq = del_vq;
 671
 672         return 0;
 673
 674 err_map_device:
 675         if (vp_dev->notify_base)
 676                 pci_iounmap(pci_dev, vp_dev->notify_base);
 677 err_map_notify:
 678         pci_iounmap(pci_dev, vp_dev->isr);
 679 err_map_isr:
 680         pci_iounmap(pci_dev, vp_dev->common);
 681 err_map_common:
 682         return err;
 683 }
 684
 685 void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
 686 {
 687         struct pci_dev *pci_dev = vp_dev->pci_dev;
 688
 689         if (vp_dev->device)
 690                 pci_iounmap(pci_dev, vp_dev->device);
 691         if (vp_dev->notify_base)
 692                 pci_iounmap(pci_dev, vp_dev->notify_base);
 693         pci_iounmap(pci_dev, vp_dev->isr);
 694         pci_iounmap(pci_dev, vp_dev->common);
 695 }