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