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 #include <linux/delay.h>
  21 #define VIRTIO_PCI_NO_LEGACY
  22 #include "virtio_pci_common.h"
  23
  24 /*
  25  * Type-safe wrappers for io accesses.
  26  * Use these to enforce at compile time the following spec requirement:
  27  *
  28  * The driver MUST access each field using the “natural” access
  29  * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses
  30  * for 16-bit fields and 8-bit accesses for 8-bit fields.
  31  */
  32 static inline u8 vp_ioread8(u8 __iomem *addr)
  33 {
  34         return ioread8(addr);
  35 }
  36 static inline u16 vp_ioread16 (__le16 __iomem *addr)
  37 {
  38         return ioread16(addr);
  39 }
  40
  41 static inline u32 vp_ioread32(__le32 __iomem *addr)
  42 {
  43         return ioread32(addr);
  44 }
  45
  46 static inline void vp_iowrite8(u8 value, u8 __iomem *addr)
  47 {
  48         iowrite8(value, addr);
  49 }
  50
  51 static inline void vp_iowrite16(u16 value, __le16 __iomem *addr)
  52 {
  53         iowrite16(value, addr);
  54 }
  55
  56 static inline void vp_iowrite32(u32 value, __le32 __iomem *addr)
  57 {
  58         iowrite32(value, addr);
  59 }
  60
  61 static void vp_iowrite64_twopart(u64 val,
  62                                  __le32 __iomem *lo, __le32 __iomem *hi)
  63 {
  64         vp_iowrite32((u32)val, lo);
  65         vp_iowrite32(val >> 32, hi);
  66 }
  67
  68 static void __iomem *map_capability(struct pci_dev *dev, int off,
  69                                     size_t minlen,
  70                                     u32 align,
  71                                     u32 start, u32 size,
  72                                     size_t *len)
  73 {
  74         u8 bar;
  75         u32 offset, length;
  76         void __iomem *p;
  77
  78         pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
  79                                                  bar),
  80                              &bar);
  81         pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
  82                              &offset);
  83         pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
  84                               &length);
  85
  86         if (length <= start) {
  87                 dev_err(&dev->dev,
  88                         "virtio_pci: bad capability len %u (>%u expected)\n",
  89                         length, start);
  90                 return NULL;
  91         }
  92
  93         if (length - start < minlen) {
  94                 dev_err(&dev->dev,
  95                         "virtio_pci: bad capability len %u (>=%zu expected)\n",
  96                         length, minlen);
  97                 return NULL;
  98         }
  99
 100         length -= start;
 101
 102         if (start + offset < offset) {
 103                 dev_err(&dev->dev,
 104                         "virtio_pci: map wrap-around %u+%u\n",
 105                         start, offset);
 106                 return NULL;
 107         }
 108
 109         offset += start;
 110
 111         if (offset & (align - 1)) {
 112                 dev_err(&dev->dev,
 113                         "virtio_pci: offset %u not aligned to %u\n",
 114                         offset, align);
 115                 return NULL;
 116         }
 117
 118         if (length > size)
 119                 length = size;
 120
 121         if (len)
 122                 *len = length;
 123
 124         if (minlen + offset < minlen ||
 125             minlen + offset > pci_resource_len(dev, bar)) {
 126                 dev_err(&dev->dev,
 127                         "virtio_pci: map virtio %zu@%u "
 128                         "out of range on bar %i length %lu\n",
 129                         minlen, offset,
 130                         bar, (unsigned long)pci_resource_len(dev, bar));
 131                 return NULL;
 132         }
 133
 134         p = pci_iomap_range(dev, bar, offset, length);
 135         if (!p)
 136                 dev_err(&dev->dev,
 137                         "virtio_pci: unable to map virtio %u@%u on bar %i\n",
 138                         length, offset, bar);
 139         return p;
 140 }
 141
 142 /* virtio config->get_features() implementation */
 143 static u64 vp_get_features(struct virtio_device *vdev)
 144 {
 145         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 146         u64 features;
 147
 148         vp_iowrite32(0, &vp_dev->common->device_feature_select);
 149         features = vp_ioread32(&vp_dev->common->device_feature);
 150         vp_iowrite32(1, &vp_dev->common->device_feature_select);
 151         features |= ((u64)vp_ioread32(&vp_dev->common->device_feature) << 32);
 152
 153         return features;
 154 }
 155
 156 static void vp_transport_features(struct virtio_device *vdev, u64 features)
 157 {
 158         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 159         struct pci_dev *pci_dev = vp_dev->pci_dev;
 160
 161         if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) &&
 162                         pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV))
 163                 __virtio_set_bit(vdev, VIRTIO_F_SR_IOV);
 164 }
 165
 166 /* virtio config->finalize_features() implementation */
 167 static int vp_finalize_features(struct virtio_device *vdev)
 168 {
 169         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 170         u64 features = vdev->features;
 171
 172         /* Give virtio_ring a chance to accept features. */
 173         vring_transport_features(vdev);
 174
 175         /* Give virtio_pci a chance to accept features. */
 176         vp_transport_features(vdev, features);
 177
 178         if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
 179                 dev_err(&vdev->dev, "virtio: device uses modern interface "
 180                         "but does not have VIRTIO_F_VERSION_1\n");
 181                 return -EINVAL;
 182         }
 183
 184         vp_iowrite32(0, &vp_dev->common->guest_feature_select);
 185         vp_iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);
 186         vp_iowrite32(1, &vp_dev->common->guest_feature_select);
 187         vp_iowrite32(vdev->features >> 32, &vp_dev->common->guest_feature);
 188
 189         return 0;
 190 }
 191
 192 /* virtio config->get() implementation */
 193 static void vp_get(struct virtio_device *vdev, unsigned offset,
 194                    void *buf, unsigned len)
 195 {
 196         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 197         u8 b;
 198         __le16 w;
 199         __le32 l;
 200
 201         BUG_ON(offset + len > vp_dev->device_len);
 202
 203         switch (len) {
 204         case 1:
 205                 b = ioread8(vp_dev->device + offset);
 206                 memcpy(buf, &b, sizeof b);
 207                 break;
 208         case 2:
 209                 w = cpu_to_le16(ioread16(vp_dev->device + offset));
 210                 memcpy(buf, &w, sizeof w);
 211                 break;
 212         case 4:
 213                 l = cpu_to_le32(ioread32(vp_dev->device + offset));
 214                 memcpy(buf, &l, sizeof l);
 215                 break;
 216         case 8:
 217                 l = cpu_to_le32(ioread32(vp_dev->device + offset));
 218                 memcpy(buf, &l, sizeof l);
 219                 l = cpu_to_le32(ioread32(vp_dev->device + offset + sizeof l));
 220                 memcpy(buf + sizeof l, &l, sizeof l);
 221                 break;
 222         default:
 223                 BUG();
 224         }
 225 }
 226
 227 /* the config->set() implementation.  it's symmetric to the config->get()
 228  * implementation */
 229 static void vp_set(struct virtio_device *vdev, unsigned offset,
 230                    const void *buf, unsigned len)
 231 {
 232         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 233         u8 b;
 234         __le16 w;
 235         __le32 l;
 236
 237         BUG_ON(offset + len > vp_dev->device_len);
 238
 239         switch (len) {
 240         case 1:
 241                 memcpy(&b, buf, sizeof b);
 242                 iowrite8(b, vp_dev->device + offset);
 243                 break;
 244         case 2:
 245                 memcpy(&w, buf, sizeof w);
 246                 iowrite16(le16_to_cpu(w), vp_dev->device + offset);
 247                 break;
 248         case 4:
 249                 memcpy(&l, buf, sizeof l);
 250                 iowrite32(le32_to_cpu(l), vp_dev->device + offset);
 251                 break;
 252         case 8:
 253                 memcpy(&l, buf, sizeof l);
 254                 iowrite32(le32_to_cpu(l), vp_dev->device + offset);
 255                 memcpy(&l, buf + sizeof l, sizeof l);
 256                 iowrite32(le32_to_cpu(l), vp_dev->device + offset + sizeof l);
 257                 break;
 258         default:
 259                 BUG();
 260         }
 261 }
 262
 263 static u32 vp_generation(struct virtio_device *vdev)
 264 {
 265         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 266         return vp_ioread8(&vp_dev->common->config_generation);
 267 }
 268
 269 /* config->{get,set}_status() implementations */
 270 static u8 vp_get_status(struct virtio_device *vdev)
 271 {
 272         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 273         return vp_ioread8(&vp_dev->common->device_status);
 274 }
 275
 276 static void vp_set_status(struct virtio_device *vdev, u8 status)
 277 {
 278         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 279         /* We should never be setting status to 0. */
 280         BUG_ON(status == 0);
 281         vp_iowrite8(status, &vp_dev->common->device_status);
 282 }
 283
 284 static void vp_reset(struct virtio_device *vdev)
 285 {
 286         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 287         /* 0 status means a reset. */
 288         vp_iowrite8(0, &vp_dev->common->device_status);
 289         /* After writing 0 to device_status, the driver MUST wait for a read of
 290          * device_status to return 0 before reinitializing the device.
 291          * This will flush out the status write, and flush in device writes,
 292          * including MSI-X interrupts, if any.
 293          */
 294         while (vp_ioread8(&vp_dev->common->device_status))
 295                 msleep(1);
 296         /* Flush pending VQ/configuration callbacks. */
 297         vp_synchronize_vectors(vdev);
 298 }
 299
 300 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
 301 {
 302         /* Setup the vector used for configuration events */
 303         vp_iowrite16(vector, &vp_dev->common->msix_config);
 304         /* Verify we had enough resources to assign the vector */
 305         /* Will also flush the write out to device */
 306         return vp_ioread16(&vp_dev->common->msix_config);
 307 }
 308
 309 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 310                                   struct virtio_pci_vq_info *info,
 311                                   unsigned index,
 312                                   void (*callback)(struct virtqueue *vq),
 313                                   const char *name,
 314                                   bool ctx,
 315                                   u16 msix_vec)
 316 {
 317         struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
 318         struct virtqueue *vq;
 319         u16 num, off;
 320         int err;
 321
 322         if (index >= vp_ioread16(&cfg->num_queues))
 323                 return ERR_PTR(-ENOENT);
 324
 325         /* Select the queue we're interested in */
 326         vp_iowrite16(index, &cfg->queue_select);
 327
 328         /* Check if queue is either not available or already active. */
 329         num = vp_ioread16(&cfg->queue_size);
 330         if (!num || vp_ioread16(&cfg->queue_enable))
 331                 return ERR_PTR(-ENOENT);
 332
 333         if (num & (num - 1)) {
 334                 dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);
 335                 return ERR_PTR(-EINVAL);
 336         }
 337
 338         /* get offset of notification word for this vq */
 339         off = vp_ioread16(&cfg->queue_notify_off);
 340
 341         info->msix_vector = msix_vec;
 342
 343         /* create the vring */
 344         vq = vring_create_virtqueue(index, num,
 345                                     SMP_CACHE_BYTES, &vp_dev->vdev,
 346                                     true, true, ctx,
 347                                     vp_notify, callback, name);
 348         if (!vq)
 349                 return ERR_PTR(-ENOMEM);
 350
 351         /* activate the queue */
 352         vp_iowrite16(virtqueue_get_vring_size(vq), &cfg->queue_size);
 353         vp_iowrite64_twopart(virtqueue_get_desc_addr(vq),
 354                              &cfg->queue_desc_lo, &cfg->queue_desc_hi);
 355         vp_iowrite64_twopart(virtqueue_get_avail_addr(vq),
 356                              &cfg->queue_avail_lo, &cfg->queue_avail_hi);
 357         vp_iowrite64_twopart(virtqueue_get_used_addr(vq),
 358                              &cfg->queue_used_lo, &cfg->queue_used_hi);
 359
 360         if (vp_dev->notify_base) {
 361                 /* offset should not wrap */
 362                 if ((u64)off * vp_dev->notify_offset_multiplier + 2
 363                     > vp_dev->notify_len) {
 364                         dev_warn(&vp_dev->pci_dev->dev,
 365                                  "bad notification offset %u (x %u) "
 366                                  "for queue %u > %zd",
 367                                  off, vp_dev->notify_offset_multiplier,
 368                                  index, vp_dev->notify_len);
 369                         err = -EINVAL;
 370                         goto err_map_notify;
 371                 }
 372                 vq->priv = (void __force *)vp_dev->notify_base +
 373                         off * vp_dev->notify_offset_multiplier;
 374         } else {
 375                 vq->priv = (void __force *)map_capability(vp_dev->pci_dev,
 376                                           vp_dev->notify_map_cap, 2, 2,
 377                                           off * vp_dev->notify_offset_multiplier, 2,
 378                                           NULL);
 379         }
 380
 381         if (!vq->priv) {
 382                 err = -ENOMEM;
 383                 goto err_map_notify;
 384         }
 385
 386         if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
 387                 vp_iowrite16(msix_vec, &cfg->queue_msix_vector);
 388                 msix_vec = vp_ioread16(&cfg->queue_msix_vector);
 389                 if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
 390                         err = -EBUSY;
 391                         goto err_assign_vector;
 392                 }
 393         }
 394
 395         return vq;
 396
 397 err_assign_vector:
 398         if (!vp_dev->notify_base)
 399                 pci_iounmap(vp_dev->pci_dev, (void __iomem __force *)vq->priv);
 400 err_map_notify:
 401         vring_del_virtqueue(vq);
 402         return ERR_PTR(err);
 403 }
 404
 405 static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 406                               struct virtqueue *vqs[],
 407                               vq_callback_t *callbacks[],
 408                               const char * const names[], const bool *ctx,
 409                               struct irq_affinity *desc)
 410 {
 411         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 412         struct virtqueue *vq;
 413         int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names, ctx, desc);
 414
 415         if (rc)
 416                 return rc;
 417
 418         /* Select and activate all queues. Has to be done last: once we do
 419          * this, there's no way to go back except reset.
 420          */
 421         list_for_each_entry(vq, &vdev->vqs, list) {
 422                 vp_iowrite16(vq->index, &vp_dev->common->queue_select);
 423                 vp_iowrite16(1, &vp_dev->common->queue_enable);
 424         }
 425
 426         return 0;
 427 }
 428
 429 static void del_vq(struct virtio_pci_vq_info *info)
 430 {
 431         struct virtqueue *vq = info->vq;
 432         struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 433
 434         vp_iowrite16(vq->index, &vp_dev->common->queue_select);
 435
 436         if (vp_dev->msix_enabled) {
 437                 vp_iowrite16(VIRTIO_MSI_NO_VECTOR,
 438                              &vp_dev->common->queue_msix_vector);
 439                 /* Flush the write out to device */
 440                 vp_ioread16(&vp_dev->common->queue_msix_vector);
 441         }
 442
 443         if (!vp_dev->notify_base)
 444                 pci_iounmap(vp_dev->pci_dev, (void __force __iomem *)vq->priv);
 445
 446         vring_del_virtqueue(vq);
 447 }
 448
 449 static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
 450         .get            = NULL,
 451         .set            = NULL,
 452         .generation     = vp_generation,
 453         .get_status     = vp_get_status,
 454         .set_status     = vp_set_status,
 455         .reset          = vp_reset,
 456         .find_vqs       = vp_modern_find_vqs,
 457         .del_vqs        = vp_del_vqs,
 458         .get_features   = vp_get_features,
 459         .finalize_features = vp_finalize_features,
 460         .bus_name       = vp_bus_name,
 461         .set_vq_affinity = vp_set_vq_affinity,
 462         .get_vq_affinity = vp_get_vq_affinity,
 463 };
 464
 465 static const struct virtio_config_ops virtio_pci_config_ops = {
 466         .get            = vp_get,
 467         .set            = vp_set,
 468         .generation     = vp_generation,
 469         .get_status     = vp_get_status,
 470         .set_status     = vp_set_status,
 471         .reset          = vp_reset,
 472         .find_vqs       = vp_modern_find_vqs,
 473         .del_vqs        = vp_del_vqs,
 474         .get_features   = vp_get_features,
 475         .finalize_features = vp_finalize_features,
 476         .bus_name       = vp_bus_name,
 477         .set_vq_affinity = vp_set_vq_affinity,
 478         .get_vq_affinity = vp_get_vq_affinity,
 479 };
 480
 481 /**
 482  * virtio_pci_find_capability - walk capabilities to find device info.
 483  * @dev: the pci device
 484  * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
 485  * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
 486  *
 487  * Returns offset of the capability, or 0.
 488  */
 489 static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
 490                                              u32 ioresource_types, int *bars)
 491 {
 492         int pos;
 493
 494         for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
 495              pos > 0;
 496              pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
 497                 u8 type, bar;
 498                 pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
 499                                                          cfg_type),
 500                                      &type);
 501                 pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
 502                                                          bar),
 503                                      &bar);
 504
 505                 /* Ignore structures with reserved BAR values */
 506                 if (bar > 0x5)
 507                         continue;
 508
 509                 if (type == cfg_type) {
 510                         if (pci_resource_len(dev, bar) &&
 511                             pci_resource_flags(dev, bar) & ioresource_types) {
 512                                 *bars |= (1 << bar);
 513                                 return pos;
 514                         }
 515                 }
 516         }
 517         return 0;
 518 }
 519
 520 /* This is part of the ABI.  Don't screw with it. */
 521 static inline void check_offsets(void)
 522 {
 523         /* Note: disk space was harmed in compilation of this function. */
 524         BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
 525                      offsetof(struct virtio_pci_cap, cap_vndr));
 526         BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
 527                      offsetof(struct virtio_pci_cap, cap_next));
 528         BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
 529                      offsetof(struct virtio_pci_cap, cap_len));
 530         BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
 531                      offsetof(struct virtio_pci_cap, cfg_type));
 532         BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
 533                      offsetof(struct virtio_pci_cap, bar));
 534         BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
 535                      offsetof(struct virtio_pci_cap, offset));
 536         BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
 537                      offsetof(struct virtio_pci_cap, length));
 538         BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
 539                      offsetof(struct virtio_pci_notify_cap,
 540                               notify_off_multiplier));
 541         BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
 542                      offsetof(struct virtio_pci_common_cfg,
 543                               device_feature_select));
 544         BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
 545                      offsetof(struct virtio_pci_common_cfg, device_feature));
 546         BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
 547                      offsetof(struct virtio_pci_common_cfg,
 548                               guest_feature_select));
 549         BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
 550                      offsetof(struct virtio_pci_common_cfg, guest_feature));
 551         BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
 552                      offsetof(struct virtio_pci_common_cfg, msix_config));
 553         BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
 554                      offsetof(struct virtio_pci_common_cfg, num_queues));
 555         BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
 556                      offsetof(struct virtio_pci_common_cfg, device_status));
 557         BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
 558                      offsetof(struct virtio_pci_common_cfg, config_generation));
 559         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
 560                      offsetof(struct virtio_pci_common_cfg, queue_select));
 561         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
 562                      offsetof(struct virtio_pci_common_cfg, queue_size));
 563         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
 564                      offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
 565         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
 566                      offsetof(struct virtio_pci_common_cfg, queue_enable));
 567         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
 568                      offsetof(struct virtio_pci_common_cfg, queue_notify_off));
 569         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
 570                      offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
 571         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
 572                      offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
 573         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
 574                      offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
 575         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
 576                      offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
 577         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
 578                      offsetof(struct virtio_pci_common_cfg, queue_used_lo));
 579         BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
 580                      offsetof(struct virtio_pci_common_cfg, queue_used_hi));
 581 }
 582
 583 /* the PCI probing function */
 584 int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
 585 {
 586         struct pci_dev *pci_dev = vp_dev->pci_dev;
 587         int err, common, isr, notify, device;
 588         u32 notify_length;
 589         u32 notify_offset;
 590
 591         check_offsets();
 592
 593         /* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
 594         if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
 595                 return -ENODEV;
 596
 597         if (pci_dev->device < 0x1040) {
 598                 /* Transitional devices: use the PCI subsystem device id as
 599                  * virtio device id, same as legacy driver always did.
 600                  */
 601                 vp_dev->vdev.id.device = pci_dev->subsystem_device;
 602         } else {
 603                 /* Modern devices: simply use PCI device id, but start from 0x1040. */
 604                 vp_dev->vdev.id.device = pci_dev->device - 0x1040;
 605         }
 606         vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
 607
 608         /* check for a common config: if not, use legacy mode (bar 0). */
 609         common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
 610                                             IORESOURCE_IO | IORESOURCE_MEM,
 611                                             &vp_dev->modern_bars);
 612         if (!common) {
 613                 dev_info(&pci_dev->dev,
 614                          "virtio_pci: leaving for legacy driver\n");
 615                 return -ENODEV;
 616         }
 617
 618         /* If common is there, these should be too... */
 619         isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
 620                                          IORESOURCE_IO | IORESOURCE_MEM,
 621                                          &vp_dev->modern_bars);
 622         notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
 623                                             IORESOURCE_IO | IORESOURCE_MEM,
 624                                             &vp_dev->modern_bars);
 625         if (!isr || !notify) {
 626                 dev_err(&pci_dev->dev,
 627                         "virtio_pci: missing capabilities %i/%i/%i\n",
 628                         common, isr, notify);
 629                 return -EINVAL;
 630         }
 631
 632         err = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
 633         if (err)
 634                 err = dma_set_mask_and_coherent(&pci_dev->dev,
 635                                                 DMA_BIT_MASK(32));
 636         if (err)
 637                 dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
 638
 639         /* Device capability is only mandatory for devices that have
 640          * device-specific configuration.
 641          */
 642         device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
 643                                             IORESOURCE_IO | IORESOURCE_MEM,
 644                                             &vp_dev->modern_bars);
 645
 646         err = pci_request_selected_regions(pci_dev, vp_dev->modern_bars,
 647                                            "virtio-pci-modern");
 648         if (err)
 649                 return err;
 650
 651         err = -EINVAL;
 652         vp_dev->common = map_capability(pci_dev, common,
 653                                         sizeof(struct virtio_pci_common_cfg), 4,
 654                                         0, sizeof(struct virtio_pci_common_cfg),
 655                                         NULL);
 656         if (!vp_dev->common)
 657                 goto err_map_common;
 658         vp_dev->isr = map_capability(pci_dev, isr, sizeof(u8), 1,
 659                                      0, 1,
 660                                      NULL);
 661         if (!vp_dev->isr)
 662                 goto err_map_isr;
 663
 664         /* Read notify_off_multiplier from config space. */
 665         pci_read_config_dword(pci_dev,
 666                               notify + offsetof(struct virtio_pci_notify_cap,
 667                                                 notify_off_multiplier),
 668                               &vp_dev->notify_offset_multiplier);
 669         /* Read notify length and offset from config space. */
 670         pci_read_config_dword(pci_dev,
 671                               notify + offsetof(struct virtio_pci_notify_cap,
 672                                                 cap.length),
 673                               &notify_length);
 674
 675         pci_read_config_dword(pci_dev,
 676                               notify + offsetof(struct virtio_pci_notify_cap,
 677                                                 cap.offset),
 678                               &notify_offset);
 679
 680         /* We don't know how many VQs we'll map, ahead of the time.
 681          * If notify length is small, map it all now.
 682          * Otherwise, map each VQ individually later.
 683          */
 684         if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
 685                 vp_dev->notify_base = map_capability(pci_dev, notify, 2, 2,
 686                                                      0, notify_length,
 687                                                      &vp_dev->notify_len);
 688                 if (!vp_dev->notify_base)
 689                         goto err_map_notify;
 690         } else {
 691                 vp_dev->notify_map_cap = notify;
 692         }
 693
 694         /* Again, we don't know how much we should map, but PAGE_SIZE
 695          * is more than enough for all existing devices.
 696          */
 697         if (device) {
 698                 vp_dev->device = map_capability(pci_dev, device, 0, 4,
 699                                                 0, PAGE_SIZE,
 700                                                 &vp_dev->device_len);
 701                 if (!vp_dev->device)
 702                         goto err_map_device;
 703
 704                 vp_dev->vdev.config = &virtio_pci_config_ops;
 705         } else {
 706                 vp_dev->vdev.config = &virtio_pci_config_nodev_ops;
 707         }
 708
 709         vp_dev->config_vector = vp_config_vector;
 710         vp_dev->setup_vq = setup_vq;
 711         vp_dev->del_vq = del_vq;
 712
 713         return 0;
 714
 715 err_map_device:
 716         if (vp_dev->notify_base)
 717                 pci_iounmap(pci_dev, vp_dev->notify_base);
 718 err_map_notify:
 719         pci_iounmap(pci_dev, vp_dev->isr);
 720 err_map_isr:
 721         pci_iounmap(pci_dev, vp_dev->common);
 722 err_map_common:
 723         return err;
 724 }
 725
 726 void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
 727 {
 728         struct pci_dev *pci_dev = vp_dev->pci_dev;
 729
 730         if (vp_dev->device)
 731                 pci_iounmap(pci_dev, vp_dev->device);
 732         if (vp_dev->notify_base)
 733                 pci_iounmap(pci_dev, vp_dev->notify_base);
 734         pci_iounmap(pci_dev, vp_dev->isr);
 735         pci_iounmap(pci_dev, vp_dev->common);
 736         pci_release_selected_regions(pci_dev, vp_dev->modern_bars);
 737 }