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 synchronize_irq(pci_irq_vector(vp_dev->pci_dev, 0)); 37 for (i = 1; i < vp_dev->msix_vectors; i++) 38 synchronize_irq(pci_irq_vector(vp_dev->pci_dev, i)); 39 } 40 41 /* the notify function used when creating a virt queue */ 42 bool vp_notify(struct virtqueue *vq) 43 { 44 /* we write the queue's selector into the notification register to 45 * signal the other end */ 46 iowrite16(vq->index, (void __iomem *)vq->priv); 47 return true; 48 } 49 50 /* Handle a configuration change: Tell driver if it wants to know. */ 51 static irqreturn_t vp_config_changed(int irq, void *opaque) 52 { 53 struct virtio_pci_device *vp_dev = opaque; 54 55 virtio_config_changed(&vp_dev->vdev); 56 return IRQ_HANDLED; 57 } 58 59 /* Notify all virtqueues on an interrupt. */ 60 static irqreturn_t vp_vring_interrupt(int irq, void *opaque) 61 { 62 struct virtio_pci_device *vp_dev = opaque; 63 irqreturn_t ret = IRQ_NONE; 64 struct virtqueue *vq; 65 66 list_for_each_entry(vq, &vp_dev->vdev.vqs, list) { 67 if (vq->callback && vring_interrupt(irq, vq) == IRQ_HANDLED) 68 ret = IRQ_HANDLED; 69 } 70 71 return ret; 72 } 73 74 /* A small wrapper to also acknowledge the interrupt when it's handled. 75 * I really need an EIO hook for the vring so I can ack the interrupt once we 76 * know that we'll be handling the IRQ but before we invoke the callback since 77 * the callback may notify the host which results in the host attempting to 78 * raise an interrupt that we would then mask once we acknowledged the 79 * interrupt. */ 80 static irqreturn_t vp_interrupt(int irq, void *opaque) 81 { 82 struct virtio_pci_device *vp_dev = opaque; 83 u8 isr; 84 85 /* reading the ISR has the effect of also clearing it so it's very 86 * important to save off the value. */ 87 isr = ioread8(vp_dev->isr); 88 89 /* It's definitely not us if the ISR was not high */ 90 if (!isr) 91 return IRQ_NONE; 92 93 /* Configuration change? Tell driver if it wants to know. */ 94 if (isr & VIRTIO_PCI_ISR_CONFIG) 95 vp_config_changed(irq, opaque); 96 97 return vp_vring_interrupt(irq, opaque); 98 } 99 100 static void vp_remove_vqs(struct virtio_device *vdev) 101 { 102 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 103 struct virtqueue *vq, *n; 104 105 list_for_each_entry_safe(vq, n, &vdev->vqs, list) { 106 if (vp_dev->msix_vector_map) { 107 int v = vp_dev->msix_vector_map[vq->index]; 108 109 if (v != VIRTIO_MSI_NO_VECTOR) 110 free_irq(pci_irq_vector(vp_dev->pci_dev, v), 111 vq); 112 } 113 vp_dev->del_vq(vq); 114 } 115 } 116 117 /* the config->del_vqs() implementation */ 118 void vp_del_vqs(struct virtio_device *vdev) 119 { 120 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 121 int i; 122 123 if (WARN_ON_ONCE(list_empty_careful(&vdev->vqs))) 124 return; 125 126 vp_remove_vqs(vdev); 127 128 if (vp_dev->pci_dev->msix_enabled) { 129 for (i = 0; i < vp_dev->msix_vectors; i++) 130 free_cpumask_var(vp_dev->msix_affinity_masks[i]); 131 132 /* Disable the vector used for configuration */ 133 vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR); 134 135 kfree(vp_dev->msix_affinity_masks); 136 kfree(vp_dev->msix_names); 137 kfree(vp_dev->msix_vector_map); 138 } 139 140 free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev); 141 pci_free_irq_vectors(vp_dev->pci_dev); 142 } 143 144 static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs, 145 struct virtqueue *vqs[], vq_callback_t *callbacks[], 146 const char * const names[], struct irq_affinity *desc) 147 { 148 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 149 const char *name = dev_name(&vp_dev->vdev.dev); 150 int i, j, err = -ENOMEM, allocated_vectors, nvectors; 151 unsigned flags = PCI_IRQ_MSIX; 152 bool shared = false; 153 u16 msix_vec; 154 155 if (desc) { 156 flags |= PCI_IRQ_AFFINITY; 157 desc->pre_vectors++; /* virtio config vector */ 158 } 159 160 nvectors = 1; 161 for (i = 0; i < nvqs; i++) 162 if (callbacks[i]) 163 nvectors++; 164 165 /* Try one vector per queue first. */ 166 err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors, 167 nvectors, flags, desc); 168 if (err < 0) { 169 /* Fallback to one vector for config, one shared for queues. */ 170 shared = true; 171 err = pci_alloc_irq_vectors(vp_dev->pci_dev, 2, 2, 172 PCI_IRQ_MSIX); 173 if (err < 0) 174 return err; 175 } 176 if (err < 0) 177 return err; 178 179 vp_dev->msix_vectors = nvectors; 180 vp_dev->msix_names = kmalloc_array(nvectors, 181 sizeof(*vp_dev->msix_names), GFP_KERNEL); 182 if (!vp_dev->msix_names) 183 goto out_free_irq_vectors; 184 185 vp_dev->msix_affinity_masks = kcalloc(nvectors, 186 sizeof(*vp_dev->msix_affinity_masks), GFP_KERNEL); 187 if (!vp_dev->msix_affinity_masks) 188 goto out_free_msix_names; 189 190 for (i = 0; i < nvectors; ++i) { 191 if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i], 192 GFP_KERNEL)) 193 goto out_free_msix_affinity_masks; 194 } 195 196 /* Set the vector used for configuration */ 197 snprintf(vp_dev->msix_names[0], sizeof(*vp_dev->msix_names), 198 "%s-config", name); 199 err = request_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_config_changed, 200 0, vp_dev->msix_names[0], vp_dev); 201 if (err) 202 goto out_free_msix_affinity_masks; 203 204 /* Verify we had enough resources to assign the vector */ 205 if (vp_dev->config_vector(vp_dev, 0) == VIRTIO_MSI_NO_VECTOR) { 206 err = -EBUSY; 207 goto out_free_config_irq; 208 } 209 210 vp_dev->msix_vector_map = kmalloc_array(nvqs, 211 sizeof(*vp_dev->msix_vector_map), GFP_KERNEL); 212 if (!vp_dev->msix_vector_map) 213 goto out_disable_config_irq; 214 215 allocated_vectors = j = 1; /* vector 0 is the config interrupt */ 216 for (i = 0; i < nvqs; ++i) { 217 if (!names[i]) { 218 vqs[i] = NULL; 219 continue; 220 } 221 222 if (callbacks[i]) 223 msix_vec = allocated_vectors; 224 else 225 msix_vec = VIRTIO_MSI_NO_VECTOR; 226 227 vqs[i] = vp_dev->setup_vq(vp_dev, i, callbacks[i], names[i], 228 msix_vec); 229 if (IS_ERR(vqs[i])) { 230 err = PTR_ERR(vqs[i]); 231 goto out_remove_vqs; 232 } 233 234 if (msix_vec == VIRTIO_MSI_NO_VECTOR) { 235 vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR; 236 continue; 237 } 238 239 snprintf(vp_dev->msix_names[j], 240 sizeof(*vp_dev->msix_names), "%s-%s", 241 dev_name(&vp_dev->vdev.dev), names[i]); 242 err = request_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec), 243 vring_interrupt, IRQF_SHARED, 244 vp_dev->msix_names[j], vqs[i]); 245 if (err) { 246 /* don't free this irq on error */ 247 vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR; 248 goto out_remove_vqs; 249 } 250 vp_dev->msix_vector_map[i] = msix_vec; 251 j++; 252 253 /* 254 * Use a different vector for each queue if they are available, 255 * else share the same vector for all VQs. 256 */ 257 if (!shared) 258 allocated_vectors++; 259 } 260 261 return 0; 262 263 out_remove_vqs: 264 vp_remove_vqs(vdev); 265 kfree(vp_dev->msix_vector_map); 266 out_disable_config_irq: 267 vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR); 268 out_free_config_irq: 269 free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev); 270 out_free_msix_affinity_masks: 271 for (i = 0; i < nvectors; i++) { 272 if (vp_dev->msix_affinity_masks[i]) 273 free_cpumask_var(vp_dev->msix_affinity_masks[i]); 274 } 275 kfree(vp_dev->msix_affinity_masks); 276 out_free_msix_names: 277 kfree(vp_dev->msix_names); 278 out_free_irq_vectors: 279 pci_free_irq_vectors(vp_dev->pci_dev); 280 return err; 281 } 282 283 static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs, 284 struct virtqueue *vqs[], vq_callback_t *callbacks[], 285 const char * const names[]) 286 { 287 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 288 int i, err; 289 290 err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED, 291 dev_name(&vdev->dev), vp_dev); 292 if (err) 293 return err; 294 295 for (i = 0; i < nvqs; ++i) { 296 if (!names[i]) { 297 vqs[i] = NULL; 298 continue; 299 } 300 vqs[i] = vp_dev->setup_vq(vp_dev, i, callbacks[i], names[i], 301 VIRTIO_MSI_NO_VECTOR); 302 if (IS_ERR(vqs[i])) { 303 err = PTR_ERR(vqs[i]); 304 goto out_remove_vqs; 305 } 306 } 307 308 return 0; 309 310 out_remove_vqs: 311 vp_remove_vqs(vdev); 312 free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev); 313 return err; 314 } 315 316 /* the config->find_vqs() implementation */ 317 int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, 318 struct virtqueue *vqs[], vq_callback_t *callbacks[], 319 const char * const names[], struct irq_affinity *desc) 320 { 321 int err; 322 323 err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, desc); 324 if (!err) 325 return 0; 326 return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names); 327 } 328 329 const char *vp_bus_name(struct virtio_device *vdev) 330 { 331 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 332 333 return pci_name(vp_dev->pci_dev); 334 } 335 336 /* Setup the affinity for a virtqueue: 337 * - force the affinity for per vq vector 338 * - OR over all affinities for shared MSI 339 * - ignore the affinity request if we're using INTX 340 */ 341 int vp_set_vq_affinity(struct virtqueue *vq, int cpu) 342 { 343 struct virtio_device *vdev = vq->vdev; 344 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 345 346 if (!vq->callback) 347 return -EINVAL; 348 349 if (vp_dev->pci_dev->msix_enabled) { 350 int vec = vp_dev->msix_vector_map[vq->index]; 351 struct cpumask *mask = vp_dev->msix_affinity_masks[vec]; 352 unsigned int irq = pci_irq_vector(vp_dev->pci_dev, vec); 353 354 if (cpu == -1) 355 irq_set_affinity_hint(irq, NULL); 356 else { 357 cpumask_clear(mask); 358 cpumask_set_cpu(cpu, mask); 359 irq_set_affinity_hint(irq, mask); 360 } 361 } 362 return 0; 363 } 364 365 const struct cpumask *vp_get_vq_affinity(struct virtio_device *vdev, int index) 366 { 367 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 368 unsigned int *map = vp_dev->msix_vector_map; 369 370 if (!map || map[index] == VIRTIO_MSI_NO_VECTOR) 371 return NULL; 372 373 return pci_irq_get_affinity(vp_dev->pci_dev, map[index]); 374 } 375 376 #ifdef CONFIG_PM_SLEEP 377 static int virtio_pci_freeze(struct device *dev) 378 { 379 struct pci_dev *pci_dev = to_pci_dev(dev); 380 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 381 int ret; 382 383 ret = virtio_device_freeze(&vp_dev->vdev); 384 385 if (!ret) 386 pci_disable_device(pci_dev); 387 return ret; 388 } 389 390 static int virtio_pci_restore(struct device *dev) 391 { 392 struct pci_dev *pci_dev = to_pci_dev(dev); 393 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 394 int ret; 395 396 ret = pci_enable_device(pci_dev); 397 if (ret) 398 return ret; 399 400 pci_set_master(pci_dev); 401 return virtio_device_restore(&vp_dev->vdev); 402 } 403 404 static const struct dev_pm_ops virtio_pci_pm_ops = { 405 SET_SYSTEM_SLEEP_PM_OPS(virtio_pci_freeze, virtio_pci_restore) 406 }; 407 #endif 408 409 410 /* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */ 411 static const struct pci_device_id virtio_pci_id_table[] = { 412 { PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID) }, 413 { 0 } 414 }; 415 416 MODULE_DEVICE_TABLE(pci, virtio_pci_id_table); 417 418 static void virtio_pci_release_dev(struct device *_d) 419 { 420 struct virtio_device *vdev = dev_to_virtio(_d); 421 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 422 423 /* As struct device is a kobject, it's not safe to 424 * free the memory (including the reference counter itself) 425 * until it's release callback. */ 426 kfree(vp_dev); 427 } 428 429 static int virtio_pci_probe(struct pci_dev *pci_dev, 430 const struct pci_device_id *id) 431 { 432 struct virtio_pci_device *vp_dev; 433 int rc; 434 435 /* allocate our structure and fill it out */ 436 vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL); 437 if (!vp_dev) 438 return -ENOMEM; 439 440 pci_set_drvdata(pci_dev, vp_dev); 441 vp_dev->vdev.dev.parent = &pci_dev->dev; 442 vp_dev->vdev.dev.release = virtio_pci_release_dev; 443 vp_dev->pci_dev = pci_dev; 444 445 /* enable the device */ 446 rc = pci_enable_device(pci_dev); 447 if (rc) 448 goto err_enable_device; 449 450 if (force_legacy) { 451 rc = virtio_pci_legacy_probe(vp_dev); 452 /* Also try modern mode if we can't map BAR0 (no IO space). */ 453 if (rc == -ENODEV || rc == -ENOMEM) 454 rc = virtio_pci_modern_probe(vp_dev); 455 if (rc) 456 goto err_probe; 457 } else { 458 rc = virtio_pci_modern_probe(vp_dev); 459 if (rc == -ENODEV) 460 rc = virtio_pci_legacy_probe(vp_dev); 461 if (rc) 462 goto err_probe; 463 } 464 465 pci_set_master(pci_dev); 466 467 rc = register_virtio_device(&vp_dev->vdev); 468 if (rc) 469 goto err_register; 470 471 return 0; 472 473 err_register: 474 if (vp_dev->ioaddr) 475 virtio_pci_legacy_remove(vp_dev); 476 else 477 virtio_pci_modern_remove(vp_dev); 478 err_probe: 479 pci_disable_device(pci_dev); 480 err_enable_device: 481 kfree(vp_dev); 482 return rc; 483 } 484 485 static void virtio_pci_remove(struct pci_dev *pci_dev) 486 { 487 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 488 struct device *dev = get_device(&vp_dev->vdev.dev); 489 490 unregister_virtio_device(&vp_dev->vdev); 491 492 if (vp_dev->ioaddr) 493 virtio_pci_legacy_remove(vp_dev); 494 else 495 virtio_pci_modern_remove(vp_dev); 496 497 pci_disable_device(pci_dev); 498 put_device(dev); 499 } 500 501 static struct pci_driver virtio_pci_driver = { 502 .name = "virtio-pci", 503 .id_table = virtio_pci_id_table, 504 .probe = virtio_pci_probe, 505 .remove = virtio_pci_remove, 506 #ifdef CONFIG_PM_SLEEP 507 .driver.pm = &virtio_pci_pm_ops, 508 #endif 509 }; 510 511 module_pci_driver(virtio_pci_driver); 512 513 MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>"); 514 MODULE_DESCRIPTION("virtio-pci"); 515 MODULE_LICENSE("GPL"); 516 MODULE_VERSION("1"); 517