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, *reg_dev = NULL; 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 reg_dev = vp_dev; 555 if (rc) 556 goto err_register; 557 558 return 0; 559 560 err_register: 561 if (vp_dev->ioaddr) 562 virtio_pci_legacy_remove(vp_dev); 563 else 564 virtio_pci_modern_remove(vp_dev); 565 err_probe: 566 pci_disable_device(pci_dev); 567 err_enable_device: 568 if (reg_dev) 569 put_device(&vp_dev->vdev.dev); 570 else 571 kfree(vp_dev); 572 return rc; 573 } 574 575 static void virtio_pci_remove(struct pci_dev *pci_dev) 576 { 577 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 578 struct device *dev = get_device(&vp_dev->vdev.dev); 579 580 unregister_virtio_device(&vp_dev->vdev); 581 582 if (vp_dev->ioaddr) 583 virtio_pci_legacy_remove(vp_dev); 584 else 585 virtio_pci_modern_remove(vp_dev); 586 587 pci_disable_device(pci_dev); 588 put_device(dev); 589 } 590 591 static struct pci_driver virtio_pci_driver = { 592 .name = "virtio-pci", 593 .id_table = virtio_pci_id_table, 594 .probe = virtio_pci_probe, 595 .remove = virtio_pci_remove, 596 #ifdef CONFIG_PM_SLEEP 597 .driver.pm = &virtio_pci_pm_ops, 598 #endif 599 }; 600 601 module_pci_driver(virtio_pci_driver); 602 603 MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>"); 604 MODULE_DESCRIPTION("virtio-pci"); 605 MODULE_LICENSE("GPL"); 606 MODULE_VERSION("1"); 607