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