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