drivers/virtio/virtio_pci_common.c

   1 /*
   2  * Virtio PCI driver - common functionality for all device versions
   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 "virtio_pci_common.h"
  21
  22 static bool force_legacy = false;
  23
  24 #if IS_ENABLED(CONFIG_VIRTIO_PCI_LEGACY)
  25 module_param(force_legacy, bool, 0444);
  26 MODULE_PARM_DESC(force_legacy,
  27                  "Force legacy mode for transitional virtio 1 devices");
  28 #endif
  29
  30 /* wait for pending irq handlers */
  31 void vp_synchronize_vectors(struct virtio_device *vdev)
  32 {
  33         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  34         int i;
  35
  36         if (vp_dev->intx_enabled)
  37                 synchronize_irq(vp_dev->pci_dev->irq);
  38
  39         for (i = 0; i < vp_dev->msix_vectors; ++i)
  40                 synchronize_irq(pci_irq_vector(vp_dev->pci_dev, i));
  41 }
  42
  43 /* the notify function used when creating a virt queue */
  44 bool vp_notify(struct virtqueue *vq)
  45 {
  46         /* we write the queue's selector into the notification register to
  47          * signal the other end */
  48         iowrite16(vq->index, (void __iomem *)vq->priv);
  49         return true;
  50 }
  51
  52 /* Handle a configuration change: Tell driver if it wants to know. */
  53 static irqreturn_t vp_config_changed(int irq, void *opaque)
  54 {
  55         struct virtio_pci_device *vp_dev = opaque;
  56
  57         virtio_config_changed(&vp_dev->vdev);
  58         return IRQ_HANDLED;
  59 }
  60
  61 /* Notify all virtqueues on an interrupt. */
  62 static irqreturn_t vp_vring_interrupt(int irq, void *opaque)
  63 {
  64         struct virtio_pci_device *vp_dev = opaque;
  65         struct virtio_pci_vq_info *info;
  66         irqreturn_t ret = IRQ_NONE;
  67         unsigned long flags;
  68
  69         spin_lock_irqsave(&vp_dev->lock, flags);
  70         list_for_each_entry(info, &vp_dev->virtqueues, node) {
  71                 if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
  72                         ret = IRQ_HANDLED;
  73         }
  74         spin_unlock_irqrestore(&vp_dev->lock, flags);
  75
  76         return ret;
  77 }
  78
  79 /* A small wrapper to also acknowledge the interrupt when it's handled.
  80  * I really need an EIO hook for the vring so I can ack the interrupt once we
  81  * know that we'll be handling the IRQ but before we invoke the callback since
  82  * the callback may notify the host which results in the host attempting to
  83  * raise an interrupt that we would then mask once we acknowledged the
  84  * interrupt. */
  85 static irqreturn_t vp_interrupt(int irq, void *opaque)
  86 {
  87         struct virtio_pci_device *vp_dev = opaque;
  88         u8 isr;
  89
  90         /* reading the ISR has the effect of also clearing it so it's very
  91          * important to save off the value. */
  92         isr = ioread8(vp_dev->isr);
  93
  94         /* It's definitely not us if the ISR was not high */
  95         if (!isr)
  96                 return IRQ_NONE;
  97
  98         /* Configuration change?  Tell driver if it wants to know. */
  99         if (isr & VIRTIO_PCI_ISR_CONFIG)
 100                 vp_config_changed(irq, opaque);
 101
 102         return vp_vring_interrupt(irq, opaque);
 103 }
 104
 105 static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
 106                                    bool per_vq_vectors, struct irq_affinity *desc)
 107 {
 108         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 109         const char *name = dev_name(&vp_dev->vdev.dev);
 110         unsigned flags = PCI_IRQ_MSIX;
 111         unsigned i, v;
 112         int err = -ENOMEM;
 113
 114         vp_dev->msix_vectors = nvectors;
 115
 116         vp_dev->msix_names = kmalloc(nvectors * sizeof *vp_dev->msix_names,
 117                                      GFP_KERNEL);
 118         if (!vp_dev->msix_names)
 119                 goto error;
 120         vp_dev->msix_affinity_masks
 121                 = kzalloc(nvectors * sizeof *vp_dev->msix_affinity_masks,
 122                           GFP_KERNEL);
 123         if (!vp_dev->msix_affinity_masks)
 124                 goto error;
 125         for (i = 0; i < nvectors; ++i)
 126                 if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i],
 127                                         GFP_KERNEL))
 128                         goto error;
 129
 130         if (desc) {
 131                 flags |= PCI_IRQ_AFFINITY;
 132                 desc->pre_vectors++; /* virtio config vector */
 133         }
 134
 135         err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors,
 136                                              nvectors, flags, desc);
 137         if (err < 0)
 138                 goto error;
 139         vp_dev->msix_enabled = 1;
 140
 141         /* Set the vector used for configuration */
 142         v = vp_dev->msix_used_vectors;
 143         snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
 144                  "%s-config", name);
 145         err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
 146                           vp_config_changed, 0, vp_dev->msix_names[v],
 147                           vp_dev);
 148         if (err)
 149                 goto error;
 150         ++vp_dev->msix_used_vectors;
 151
 152         v = vp_dev->config_vector(vp_dev, v);
 153         /* Verify we had enough resources to assign the vector */
 154         if (v == VIRTIO_MSI_NO_VECTOR) {
 155                 err = -EBUSY;
 156                 goto error;
 157         }
 158
 159         if (!per_vq_vectors) {
 160                 /* Shared vector for all VQs */
 161                 v = vp_dev->msix_used_vectors;
 162                 snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
 163                          "%s-virtqueues", name);
 164                 err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
 165                                   vp_vring_interrupt, 0, vp_dev->msix_names[v],
 166                                   vp_dev);
 167                 if (err)
 168                         goto error;
 169                 ++vp_dev->msix_used_vectors;
 170         }
 171         return 0;
 172 error:
 173         return err;
 174 }
 175
 176 static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
 177                                      void (*callback)(struct virtqueue *vq),
 178                                      const char *name,
 179                                      bool ctx,
 180                                      u16 msix_vec)
 181 {
 182         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 183         struct virtio_pci_vq_info *info = kmalloc(sizeof *info, GFP_KERNEL);
 184         struct virtqueue *vq;
 185         unsigned long flags;
 186
 187         /* fill out our structure that represents an active queue */
 188         if (!info)
 189                 return ERR_PTR(-ENOMEM);
 190
 191         vq = vp_dev->setup_vq(vp_dev, info, index, callback, name, ctx,
 192                               msix_vec);
 193         if (IS_ERR(vq))
 194                 goto out_info;
 195
 196         info->vq = vq;
 197         if (callback) {
 198                 spin_lock_irqsave(&vp_dev->lock, flags);
 199                 list_add(&info->node, &vp_dev->virtqueues);
 200                 spin_unlock_irqrestore(&vp_dev->lock, flags);
 201         } else {
 202                 INIT_LIST_HEAD(&info->node);
 203         }
 204
 205         vp_dev->vqs[index] = info;
 206         return vq;
 207
 208 out_info:
 209         kfree(info);
 210         return vq;
 211 }
 212
 213 static void vp_del_vq(struct virtqueue *vq)
 214 {
 215         struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 216         struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
 217         unsigned long flags;
 218
 219         spin_lock_irqsave(&vp_dev->lock, flags);
 220         list_del(&info->node);
 221         spin_unlock_irqrestore(&vp_dev->lock, flags);
 222
 223         vp_dev->del_vq(info);
 224         kfree(info);
 225 }
 226
 227 /* the config->del_vqs() implementation */
 228 void vp_del_vqs(struct virtio_device *vdev)
 229 {
 230         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 231         struct virtqueue *vq, *n;
 232         int i;
 233
 234         list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
 235                 if (vp_dev->per_vq_vectors) {
 236                         int v = vp_dev->vqs[vq->index]->msix_vector;
 237
 238                         if (v != VIRTIO_MSI_NO_VECTOR) {
 239                                 int irq = pci_irq_vector(vp_dev->pci_dev, v);
 240
 241                                 irq_set_affinity_hint(irq, NULL);
 242                                 free_irq(irq, vq);
 243                         }
 244                 }
 245                 vp_del_vq(vq);
 246         }
 247         vp_dev->per_vq_vectors = false;
 248
 249         if (vp_dev->intx_enabled) {
 250                 free_irq(vp_dev->pci_dev->irq, vp_dev);
 251                 vp_dev->intx_enabled = 0;
 252         }
 253
 254         for (i = 0; i < vp_dev->msix_used_vectors; ++i)
 255                 free_irq(pci_irq_vector(vp_dev->pci_dev, i), vp_dev);
 256
 257         for (i = 0; i < vp_dev->msix_vectors; i++)
 258                 if (vp_dev->msix_affinity_masks[i])
 259                         free_cpumask_var(vp_dev->msix_affinity_masks[i]);
 260
 261         if (vp_dev->msix_enabled) {
 262                 /* Disable the vector used for configuration */
 263                 vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR);
 264
 265                 pci_free_irq_vectors(vp_dev->pci_dev);
 266                 vp_dev->msix_enabled = 0;
 267         }
 268
 269         vp_dev->msix_vectors = 0;
 270         vp_dev->msix_used_vectors = 0;
 271         kfree(vp_dev->msix_names);
 272         vp_dev->msix_names = NULL;
 273         kfree(vp_dev->msix_affinity_masks);
 274         vp_dev->msix_affinity_masks = NULL;
 275         kfree(vp_dev->vqs);
 276         vp_dev->vqs = NULL;
 277 }
 278
 279 static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
 280                 struct virtqueue *vqs[], vq_callback_t *callbacks[],
 281                 const char * const names[], bool per_vq_vectors,
 282                 const bool *ctx,
 283                 struct irq_affinity *desc)
 284 {
 285         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 286         u16 msix_vec;
 287         int i, err, nvectors, allocated_vectors;
 288
 289         vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
 290         if (!vp_dev->vqs)
 291                 return -ENOMEM;
 292
 293         if (per_vq_vectors) {
 294                 /* Best option: one for change interrupt, one per vq. */
 295                 nvectors = 1;
 296                 for (i = 0; i < nvqs; ++i)
 297                         if (callbacks[i])
 298                                 ++nvectors;
 299         } else {
 300                 /* Second best: one for change, shared for all vqs. */
 301                 nvectors = 2;
 302         }
 303
 304         err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors,
 305                                       per_vq_vectors ? desc : NULL);
 306         if (err)
 307                 goto error_find;
 308
 309         vp_dev->per_vq_vectors = per_vq_vectors;
 310         allocated_vectors = vp_dev->msix_used_vectors;
 311         for (i = 0; i < nvqs; ++i) {
 312                 if (!names[i]) {
 313                         vqs[i] = NULL;
 314                         continue;
 315                 }
 316
 317                 if (!callbacks[i])
 318                         msix_vec = VIRTIO_MSI_NO_VECTOR;
 319                 else if (vp_dev->per_vq_vectors)
 320                         msix_vec = allocated_vectors++;
 321                 else
 322                         msix_vec = VP_MSIX_VQ_VECTOR;
 323                 vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i],
 324                                      ctx ? ctx[i] : false,
 325                                      msix_vec);
 326                 if (IS_ERR(vqs[i])) {
 327                         err = PTR_ERR(vqs[i]);
 328                         goto error_find;
 329                 }
 330
 331                 if (!vp_dev->per_vq_vectors || msix_vec == VIRTIO_MSI_NO_VECTOR)
 332                         continue;
 333
 334                 /* allocate per-vq irq if available and necessary */
 335                 snprintf(vp_dev->msix_names[msix_vec],
 336                          sizeof *vp_dev->msix_names,
 337                          "%s-%s",
 338                          dev_name(&vp_dev->vdev.dev), names[i]);
 339                 err = request_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec),
 340                                   vring_interrupt, 0,
 341                                   vp_dev->msix_names[msix_vec],
 342                                   vqs[i]);
 343                 if (err)
 344                         goto error_find;
 345         }
 346         return 0;
 347
 348 error_find:
 349         vp_del_vqs(vdev);
 350         return err;
 351 }
 352
 353 static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
 354                 struct virtqueue *vqs[], vq_callback_t *callbacks[],
 355                 const char * const names[], const bool *ctx)
 356 {
 357         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 358         int i, err;
 359
 360         vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
 361         if (!vp_dev->vqs)
 362                 return -ENOMEM;
 363
 364         err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
 365                         dev_name(&vdev->dev), vp_dev);
 366         if (err)
 367                 goto out_del_vqs;
 368
 369         vp_dev->intx_enabled = 1;
 370         vp_dev->per_vq_vectors = false;
 371         for (i = 0; i < nvqs; ++i) {
 372                 if (!names[i]) {
 373                         vqs[i] = NULL;
 374                         continue;
 375                 }
 376                 vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i],
 377                                      ctx ? ctx[i] : false,
 378                                      VIRTIO_MSI_NO_VECTOR);
 379                 if (IS_ERR(vqs[i])) {
 380                         err = PTR_ERR(vqs[i]);
 381                         goto out_del_vqs;
 382                 }
 383         }
 384
 385         return 0;
 386 out_del_vqs:
 387         vp_del_vqs(vdev);
 388         return err;
 389 }
 390
 391 /* the config->find_vqs() implementation */
 392 int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 393                 struct virtqueue *vqs[], vq_callback_t *callbacks[],
 394                 const char * const names[], const bool *ctx,
 395                 struct irq_affinity *desc)
 396 {
 397         int err;
 398
 399         /* Try MSI-X with one vector per queue. */
 400         err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, true, ctx, desc);
 401         if (!err)
 402                 return 0;
 403         /* Fallback: MSI-X with one vector for config, one shared for queues. */
 404         err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, false, ctx, desc);
 405         if (!err)
 406                 return 0;
 407         /* Finally fall back to regular interrupts. */
 408         return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names, ctx);
 409 }
 410
 411 const char *vp_bus_name(struct virtio_device *vdev)
 412 {
 413         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 414
 415         return pci_name(vp_dev->pci_dev);
 416 }
 417
 418 /* Setup the affinity for a virtqueue:
 419  * - force the affinity for per vq vector
 420  * - OR over all affinities for shared MSI
 421  * - ignore the affinity request if we're using INTX
 422  */
 423 int vp_set_vq_affinity(struct virtqueue *vq, int cpu)
 424 {
 425         struct virtio_device *vdev = vq->vdev;
 426         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 427         struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
 428         struct cpumask *mask;
 429         unsigned int irq;
 430
 431         if (!vq->callback)
 432                 return -EINVAL;
 433
 434         if (vp_dev->msix_enabled) {
 435                 mask = vp_dev->msix_affinity_masks[info->msix_vector];
 436                 irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector);
 437                 if (cpu == -1)
 438                         irq_set_affinity_hint(irq, NULL);
 439                 else {
 440                         cpumask_clear(mask);
 441                         cpumask_set_cpu(cpu, mask);
 442                         irq_set_affinity_hint(irq, mask);
 443                 }
 444         }
 445         return 0;
 446 }
 447
 448 const struct cpumask *vp_get_vq_affinity(struct virtio_device *vdev, int index)
 449 {
 450         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 451
 452         if (!vp_dev->per_vq_vectors ||
 453             vp_dev->vqs[index]->msix_vector == VIRTIO_MSI_NO_VECTOR)
 454                 return NULL;
 455
 456         return pci_irq_get_affinity(vp_dev->pci_dev,
 457                                     vp_dev->vqs[index]->msix_vector);
 458 }
 459
 460 #ifdef CONFIG_PM_SLEEP
 461 static int virtio_pci_freeze(struct device *dev)
 462 {
 463         struct pci_dev *pci_dev = to_pci_dev(dev);
 464         struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
 465         int ret;
 466
 467         ret = virtio_device_freeze(&vp_dev->vdev);
 468
 469         if (!ret)
 470                 pci_disable_device(pci_dev);
 471         return ret;
 472 }
 473
 474 static int virtio_pci_restore(struct device *dev)
 475 {
 476         struct pci_dev *pci_dev = to_pci_dev(dev);
 477         struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
 478         int ret;
 479
 480         ret = pci_enable_device(pci_dev);
 481         if (ret)
 482                 return ret;
 483
 484         pci_set_master(pci_dev);
 485         return virtio_device_restore(&vp_dev->vdev);
 486 }
 487
 488 static const struct dev_pm_ops virtio_pci_pm_ops = {
 489         SET_SYSTEM_SLEEP_PM_OPS(virtio_pci_freeze, virtio_pci_restore)
 490 };
 491 #endif
 492
 493
 494 /* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */
 495 static const struct pci_device_id virtio_pci_id_table[] = {
 496         { PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID) },
 497         { 0 }
 498 };
 499
 500 MODULE_DEVICE_TABLE(pci, virtio_pci_id_table);
 501
 502 static void virtio_pci_release_dev(struct device *_d)
 503 {
 504         struct virtio_device *vdev = dev_to_virtio(_d);
 505         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 506
 507         /* As struct device is a kobject, it's not safe to
 508          * free the memory (including the reference counter itself)
 509          * until it's release callback. */
 510         kfree(vp_dev);
 511 }
 512
 513 static int virtio_pci_probe(struct pci_dev *pci_dev,
 514                             const struct pci_device_id *id)
 515 {
 516         struct virtio_pci_device *vp_dev;
 517         int rc;
 518
 519         /* allocate our structure and fill it out */
 520         vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
 521         if (!vp_dev)
 522                 return -ENOMEM;
 523
 524         pci_set_drvdata(pci_dev, vp_dev);
 525         vp_dev->vdev.dev.parent = &pci_dev->dev;
 526         vp_dev->vdev.dev.release = virtio_pci_release_dev;
 527         vp_dev->pci_dev = pci_dev;
 528         INIT_LIST_HEAD(&vp_dev->virtqueues);
 529         spin_lock_init(&vp_dev->lock);
 530
 531         /* enable the device */
 532         rc = pci_enable_device(pci_dev);
 533         if (rc)
 534                 goto err_enable_device;
 535
 536         if (force_legacy) {
 537                 rc = virtio_pci_legacy_probe(vp_dev);
 538                 /* Also try modern mode if we can't map BAR0 (no IO space). */
 539                 if (rc == -ENODEV || rc == -ENOMEM)
 540                         rc = virtio_pci_modern_probe(vp_dev);
 541                 if (rc)
 542                         goto err_probe;
 543         } else {
 544                 rc = virtio_pci_modern_probe(vp_dev);
 545                 if (rc == -ENODEV)
 546                         rc = virtio_pci_legacy_probe(vp_dev);
 547                 if (rc)
 548                         goto err_probe;
 549         }
 550
 551         pci_set_master(pci_dev);
 552
 553         rc = register_virtio_device(&vp_dev->vdev);
 554         if (rc)
 555                 goto err_register;
 556
 557         return 0;
 558
 559 err_register:
 560         if (vp_dev->ioaddr)
 561              virtio_pci_legacy_remove(vp_dev);
 562         else
 563              virtio_pci_modern_remove(vp_dev);
 564 err_probe:
 565         pci_disable_device(pci_dev);
 566 err_enable_device:
 567         kfree(vp_dev);
 568         return rc;
 569 }
 570
 571 static void virtio_pci_remove(struct pci_dev *pci_dev)
 572 {
 573         struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
 574         struct device *dev = get_device(&vp_dev->vdev.dev);
 575
 576         unregister_virtio_device(&vp_dev->vdev);
 577
 578         if (vp_dev->ioaddr)
 579                 virtio_pci_legacy_remove(vp_dev);
 580         else
 581                 virtio_pci_modern_remove(vp_dev);
 582
 583         pci_disable_device(pci_dev);
 584         put_device(dev);
 585 }
 586
 587 static struct pci_driver virtio_pci_driver = {
 588         .name           = "virtio-pci",
 589         .id_table       = virtio_pci_id_table,
 590         .probe          = virtio_pci_probe,
 591         .remove         = virtio_pci_remove,
 592 #ifdef CONFIG_PM_SLEEP
 593         .driver.pm      = &virtio_pci_pm_ops,
 594 #endif
 595 };
 596
 597 module_pci_driver(virtio_pci_driver);
 598
 599 MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
 600 MODULE_DESCRIPTION("virtio-pci");
 601 MODULE_LICENSE("GPL");
 602 MODULE_VERSION("1");