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(vp_dev->msix_entries[i].vector); 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 void vp_free_vectors(struct virtio_device *vdev) 106 { 107 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 108 int i; 109 110 if (vp_dev->intx_enabled) { 111 free_irq(vp_dev->pci_dev->irq, vp_dev); 112 vp_dev->intx_enabled = 0; 113 } 114 115 for (i = 0; i < vp_dev->msix_used_vectors; ++i) 116 free_irq(vp_dev->msix_entries[i].vector, vp_dev); 117 118 for (i = 0; i < vp_dev->msix_vectors; i++) 119 if (vp_dev->msix_affinity_masks[i]) 120 free_cpumask_var(vp_dev->msix_affinity_masks[i]); 121 122 if (vp_dev->msix_enabled) { 123 /* Disable the vector used for configuration */ 124 vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR); 125 126 pci_disable_msix(vp_dev->pci_dev); 127 vp_dev->msix_enabled = 0; 128 } 129 130 vp_dev->msix_vectors = 0; 131 vp_dev->msix_used_vectors = 0; 132 kfree(vp_dev->msix_names); 133 vp_dev->msix_names = NULL; 134 kfree(vp_dev->msix_entries); 135 vp_dev->msix_entries = NULL; 136 kfree(vp_dev->msix_affinity_masks); 137 vp_dev->msix_affinity_masks = NULL; 138 } 139 140 static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors, 141 bool per_vq_vectors) 142 { 143 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 144 const char *name = dev_name(&vp_dev->vdev.dev); 145 unsigned i, v; 146 int err = -ENOMEM; 147 148 vp_dev->msix_vectors = nvectors; 149 150 vp_dev->msix_entries = kmalloc(nvectors * sizeof *vp_dev->msix_entries, 151 GFP_KERNEL); 152 if (!vp_dev->msix_entries) 153 goto error; 154 vp_dev->msix_names = kmalloc(nvectors * sizeof *vp_dev->msix_names, 155 GFP_KERNEL); 156 if (!vp_dev->msix_names) 157 goto error; 158 vp_dev->msix_affinity_masks 159 = kzalloc(nvectors * sizeof *vp_dev->msix_affinity_masks, 160 GFP_KERNEL); 161 if (!vp_dev->msix_affinity_masks) 162 goto error; 163 for (i = 0; i < nvectors; ++i) 164 if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i], 165 GFP_KERNEL)) 166 goto error; 167 168 for (i = 0; i < nvectors; ++i) 169 vp_dev->msix_entries[i].entry = i; 170 171 err = pci_enable_msix_exact(vp_dev->pci_dev, 172 vp_dev->msix_entries, nvectors); 173 if (err) 174 goto error; 175 vp_dev->msix_enabled = 1; 176 177 /* Set the vector used for configuration */ 178 v = vp_dev->msix_used_vectors; 179 snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, 180 "%s-config", name); 181 err = request_irq(vp_dev->msix_entries[v].vector, 182 vp_config_changed, 0, vp_dev->msix_names[v], 183 vp_dev); 184 if (err) 185 goto error; 186 ++vp_dev->msix_used_vectors; 187 188 v = vp_dev->config_vector(vp_dev, v); 189 /* Verify we had enough resources to assign the vector */ 190 if (v == VIRTIO_MSI_NO_VECTOR) { 191 err = -EBUSY; 192 goto error; 193 } 194 195 if (!per_vq_vectors) { 196 /* Shared vector for all VQs */ 197 v = vp_dev->msix_used_vectors; 198 snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, 199 "%s-virtqueues", name); 200 err = request_irq(vp_dev->msix_entries[v].vector, 201 vp_vring_interrupt, 0, vp_dev->msix_names[v], 202 vp_dev); 203 if (err) 204 goto error; 205 ++vp_dev->msix_used_vectors; 206 } 207 return 0; 208 error: 209 vp_free_vectors(vdev); 210 return err; 211 } 212 213 static int vp_request_intx(struct virtio_device *vdev) 214 { 215 int err; 216 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 217 218 err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, 219 IRQF_SHARED, dev_name(&vdev->dev), vp_dev); 220 if (!err) 221 vp_dev->intx_enabled = 1; 222 return err; 223 } 224 225 static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index, 226 void (*callback)(struct virtqueue *vq), 227 const char *name, 228 u16 msix_vec) 229 { 230 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 231 struct virtio_pci_vq_info *info = kmalloc(sizeof *info, GFP_KERNEL); 232 struct virtqueue *vq; 233 unsigned long flags; 234 235 /* fill out our structure that represents an active queue */ 236 if (!info) 237 return ERR_PTR(-ENOMEM); 238 239 vq = vp_dev->setup_vq(vp_dev, info, index, callback, name, msix_vec); 240 if (IS_ERR(vq)) 241 goto out_info; 242 243 info->vq = vq; 244 if (callback) { 245 spin_lock_irqsave(&vp_dev->lock, flags); 246 list_add(&info->node, &vp_dev->virtqueues); 247 spin_unlock_irqrestore(&vp_dev->lock, flags); 248 } else { 249 INIT_LIST_HEAD(&info->node); 250 } 251 252 vp_dev->vqs[index] = info; 253 return vq; 254 255 out_info: 256 kfree(info); 257 return vq; 258 } 259 260 static void vp_del_vq(struct virtqueue *vq) 261 { 262 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); 263 struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index]; 264 unsigned long flags; 265 266 spin_lock_irqsave(&vp_dev->lock, flags); 267 list_del(&info->node); 268 spin_unlock_irqrestore(&vp_dev->lock, flags); 269 270 vp_dev->del_vq(info); 271 kfree(info); 272 } 273 274 /* the config->del_vqs() implementation */ 275 void vp_del_vqs(struct virtio_device *vdev) 276 { 277 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 278 struct virtqueue *vq, *n; 279 struct virtio_pci_vq_info *info; 280 281 list_for_each_entry_safe(vq, n, &vdev->vqs, list) { 282 info = vp_dev->vqs[vq->index]; 283 if (vp_dev->per_vq_vectors && 284 info->msix_vector != VIRTIO_MSI_NO_VECTOR) 285 free_irq(vp_dev->msix_entries[info->msix_vector].vector, 286 vq); 287 vp_del_vq(vq); 288 } 289 vp_dev->per_vq_vectors = false; 290 291 vp_free_vectors(vdev); 292 kfree(vp_dev->vqs); 293 vp_dev->vqs = NULL; 294 } 295 296 static int vp_try_to_find_vqs(struct virtio_device *vdev, unsigned nvqs, 297 struct virtqueue *vqs[], 298 vq_callback_t *callbacks[], 299 const char * const names[], 300 bool use_msix, 301 bool per_vq_vectors) 302 { 303 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 304 u16 msix_vec; 305 int i, err, nvectors, allocated_vectors; 306 307 vp_dev->vqs = kmalloc(nvqs * sizeof *vp_dev->vqs, GFP_KERNEL); 308 if (!vp_dev->vqs) 309 return -ENOMEM; 310 311 if (!use_msix) { 312 /* Old style: one normal interrupt for change and all vqs. */ 313 err = vp_request_intx(vdev); 314 if (err) 315 goto error_find; 316 } else { 317 if (per_vq_vectors) { 318 /* Best option: one for change interrupt, one per vq. */ 319 nvectors = 1; 320 for (i = 0; i < nvqs; ++i) 321 if (callbacks[i]) 322 ++nvectors; 323 } else { 324 /* Second best: one for change, shared for all vqs. */ 325 nvectors = 2; 326 } 327 328 err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors); 329 if (err) 330 goto error_find; 331 } 332 333 vp_dev->per_vq_vectors = per_vq_vectors; 334 allocated_vectors = vp_dev->msix_used_vectors; 335 for (i = 0; i < nvqs; ++i) { 336 if (!names[i]) { 337 vqs[i] = NULL; 338 continue; 339 } else if (!callbacks[i] || !vp_dev->msix_enabled) 340 msix_vec = VIRTIO_MSI_NO_VECTOR; 341 else if (vp_dev->per_vq_vectors) 342 msix_vec = allocated_vectors++; 343 else 344 msix_vec = VP_MSIX_VQ_VECTOR; 345 vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i], msix_vec); 346 if (IS_ERR(vqs[i])) { 347 err = PTR_ERR(vqs[i]); 348 goto error_find; 349 } 350 351 if (!vp_dev->per_vq_vectors || msix_vec == VIRTIO_MSI_NO_VECTOR) 352 continue; 353 354 /* allocate per-vq irq if available and necessary */ 355 snprintf(vp_dev->msix_names[msix_vec], 356 sizeof *vp_dev->msix_names, 357 "%s-%s", 358 dev_name(&vp_dev->vdev.dev), names[i]); 359 err = request_irq(vp_dev->msix_entries[msix_vec].vector, 360 vring_interrupt, 0, 361 vp_dev->msix_names[msix_vec], 362 vqs[i]); 363 if (err) { 364 vp_del_vq(vqs[i]); 365 goto error_find; 366 } 367 } 368 return 0; 369 370 error_find: 371 vp_del_vqs(vdev); 372 return err; 373 } 374 375 /* the config->find_vqs() implementation */ 376 int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, 377 struct virtqueue *vqs[], 378 vq_callback_t *callbacks[], 379 const char * const names[]) 380 { 381 int err; 382 383 /* Try MSI-X with one vector per queue. */ 384 err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, true, true); 385 if (!err) 386 return 0; 387 /* Fallback: MSI-X with one vector for config, one shared for queues. */ 388 err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, 389 true, false); 390 if (!err) 391 return 0; 392 /* Finally fall back to regular interrupts. */ 393 return vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, 394 false, false); 395 } 396 397 const char *vp_bus_name(struct virtio_device *vdev) 398 { 399 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 400 401 return pci_name(vp_dev->pci_dev); 402 } 403 404 /* Setup the affinity for a virtqueue: 405 * - force the affinity for per vq vector 406 * - OR over all affinities for shared MSI 407 * - ignore the affinity request if we're using INTX 408 */ 409 int vp_set_vq_affinity(struct virtqueue *vq, int cpu) 410 { 411 struct virtio_device *vdev = vq->vdev; 412 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 413 struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index]; 414 struct cpumask *mask; 415 unsigned int irq; 416 417 if (!vq->callback) 418 return -EINVAL; 419 420 if (vp_dev->msix_enabled) { 421 mask = vp_dev->msix_affinity_masks[info->msix_vector]; 422 irq = vp_dev->msix_entries[info->msix_vector].vector; 423 if (cpu == -1) 424 irq_set_affinity_hint(irq, NULL); 425 else { 426 cpumask_clear(mask); 427 cpumask_set_cpu(cpu, mask); 428 irq_set_affinity_hint(irq, mask); 429 } 430 } 431 return 0; 432 } 433 434 #ifdef CONFIG_PM_SLEEP 435 static int virtio_pci_freeze(struct device *dev) 436 { 437 struct pci_dev *pci_dev = to_pci_dev(dev); 438 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 439 int ret; 440 441 ret = virtio_device_freeze(&vp_dev->vdev); 442 443 if (!ret) 444 pci_disable_device(pci_dev); 445 return ret; 446 } 447 448 static int virtio_pci_restore(struct device *dev) 449 { 450 struct pci_dev *pci_dev = to_pci_dev(dev); 451 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 452 int ret; 453 454 ret = pci_enable_device(pci_dev); 455 if (ret) 456 return ret; 457 458 pci_set_master(pci_dev); 459 return virtio_device_restore(&vp_dev->vdev); 460 } 461 462 static const struct dev_pm_ops virtio_pci_pm_ops = { 463 SET_SYSTEM_SLEEP_PM_OPS(virtio_pci_freeze, virtio_pci_restore) 464 }; 465 #endif 466 467 468 /* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */ 469 static const struct pci_device_id virtio_pci_id_table[] = { 470 { PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID) }, 471 { 0 } 472 }; 473 474 MODULE_DEVICE_TABLE(pci, virtio_pci_id_table); 475 476 static void virtio_pci_release_dev(struct device *_d) 477 { 478 struct virtio_device *vdev = dev_to_virtio(_d); 479 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 480 481 /* As struct device is a kobject, it's not safe to 482 * free the memory (including the reference counter itself) 483 * until it's release callback. */ 484 kfree(vp_dev); 485 } 486 487 static int virtio_pci_probe(struct pci_dev *pci_dev, 488 const struct pci_device_id *id) 489 { 490 struct virtio_pci_device *vp_dev; 491 int rc; 492 493 /* allocate our structure and fill it out */ 494 vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL); 495 if (!vp_dev) 496 return -ENOMEM; 497 498 pci_set_drvdata(pci_dev, vp_dev); 499 vp_dev->vdev.dev.parent = &pci_dev->dev; 500 vp_dev->vdev.dev.release = virtio_pci_release_dev; 501 vp_dev->pci_dev = pci_dev; 502 INIT_LIST_HEAD(&vp_dev->virtqueues); 503 spin_lock_init(&vp_dev->lock); 504 505 /* enable the device */ 506 rc = pci_enable_device(pci_dev); 507 if (rc) 508 goto err_enable_device; 509 510 if (force_legacy) { 511 rc = virtio_pci_legacy_probe(vp_dev); 512 /* Also try modern mode if we can't map BAR0 (no IO space). */ 513 if (rc == -ENODEV || rc == -ENOMEM) 514 rc = virtio_pci_modern_probe(vp_dev); 515 if (rc) 516 goto err_probe; 517 } else { 518 rc = virtio_pci_modern_probe(vp_dev); 519 if (rc == -ENODEV) 520 rc = virtio_pci_legacy_probe(vp_dev); 521 if (rc) 522 goto err_probe; 523 } 524 525 pci_set_master(pci_dev); 526 527 rc = register_virtio_device(&vp_dev->vdev); 528 if (rc) 529 goto err_register; 530 531 return 0; 532 533 err_register: 534 if (vp_dev->ioaddr) 535 virtio_pci_legacy_remove(vp_dev); 536 else 537 virtio_pci_modern_remove(vp_dev); 538 err_probe: 539 pci_disable_device(pci_dev); 540 err_enable_device: 541 kfree(vp_dev); 542 return rc; 543 } 544 545 static void virtio_pci_remove(struct pci_dev *pci_dev) 546 { 547 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 548 struct device *dev = get_device(&vp_dev->vdev.dev); 549 550 unregister_virtio_device(&vp_dev->vdev); 551 552 if (vp_dev->ioaddr) 553 virtio_pci_legacy_remove(vp_dev); 554 else 555 virtio_pci_modern_remove(vp_dev); 556 557 pci_disable_device(pci_dev); 558 put_device(dev); 559 } 560 561 static struct pci_driver virtio_pci_driver = { 562 .name = "virtio-pci", 563 .id_table = virtio_pci_id_table, 564 .probe = virtio_pci_probe, 565 .remove = virtio_pci_remove, 566 #ifdef CONFIG_PM_SLEEP 567 .driver.pm = &virtio_pci_pm_ops, 568 #endif 569 }; 570 571 module_pci_driver(virtio_pci_driver); 572 573 MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>"); 574 MODULE_DESCRIPTION("virtio-pci"); 575 MODULE_LICENSE("GPL"); 576 MODULE_VERSION("1"); 577