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