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, 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 = 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[i + 1], 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[i + 1], 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; 251 252 /* 253 * Use a different vector for each queue if they are available, 254 * else share the same vector for all VQs. 255 */ 256 if (!shared) 257 allocated_vectors++; 258 } 259 260 return 0; 261 262 out_remove_vqs: 263 vp_remove_vqs(vdev); 264 kfree(vp_dev->msix_vector_map); 265 out_disable_config_irq: 266 vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR); 267 out_free_config_irq: 268 free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev); 269 out_free_msix_affinity_masks: 270 for (i = 0; i < nvectors; i++) { 271 if (vp_dev->msix_affinity_masks[i]) 272 free_cpumask_var(vp_dev->msix_affinity_masks[i]); 273 } 274 kfree(vp_dev->msix_affinity_masks); 275 out_free_msix_names: 276 kfree(vp_dev->msix_names); 277 out_free_irq_vectors: 278 pci_free_irq_vectors(vp_dev->pci_dev); 279 return err; 280 } 281 282 static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs, 283 struct virtqueue *vqs[], vq_callback_t *callbacks[], 284 const char * const names[]) 285 { 286 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 287 int i, err; 288 289 err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED, 290 dev_name(&vdev->dev), vp_dev); 291 if (err) 292 return err; 293 294 for (i = 0; i < nvqs; ++i) { 295 if (!names[i]) { 296 vqs[i] = NULL; 297 continue; 298 } 299 vqs[i] = vp_dev->setup_vq(vp_dev, i, callbacks[i], names[i], 300 VIRTIO_MSI_NO_VECTOR); 301 if (IS_ERR(vqs[i])) { 302 err = PTR_ERR(vqs[i]); 303 goto out_remove_vqs; 304 } 305 } 306 307 return 0; 308 309 out_remove_vqs: 310 vp_remove_vqs(vdev); 311 free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev); 312 return err; 313 } 314 315 /* the config->find_vqs() implementation */ 316 int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, 317 struct virtqueue *vqs[], vq_callback_t *callbacks[], 318 const char * const names[], struct irq_affinity *desc) 319 { 320 int err; 321 322 err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, desc); 323 if (!err) 324 return 0; 325 return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names); 326 } 327 328 const char *vp_bus_name(struct virtio_device *vdev) 329 { 330 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 331 332 return pci_name(vp_dev->pci_dev); 333 } 334 335 /* Setup the affinity for a virtqueue: 336 * - force the affinity for per vq vector 337 * - OR over all affinities for shared MSI 338 * - ignore the affinity request if we're using INTX 339 */ 340 int vp_set_vq_affinity(struct virtqueue *vq, int cpu) 341 { 342 struct virtio_device *vdev = vq->vdev; 343 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 344 345 if (!vq->callback) 346 return -EINVAL; 347 348 if (vp_dev->pci_dev->msix_enabled) { 349 int vec = vp_dev->msix_vector_map[vq->index]; 350 struct cpumask *mask = vp_dev->msix_affinity_masks[vec]; 351 unsigned int irq = pci_irq_vector(vp_dev->pci_dev, vec); 352 353 if (cpu == -1) 354 irq_set_affinity_hint(irq, NULL); 355 else { 356 cpumask_clear(mask); 357 cpumask_set_cpu(cpu, mask); 358 irq_set_affinity_hint(irq, mask); 359 } 360 } 361 return 0; 362 } 363 364 const struct cpumask *vp_get_vq_affinity(struct virtio_device *vdev, int index) 365 { 366 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 367 unsigned int *map = vp_dev->msix_vector_map; 368 369 if (!map || map[index] == VIRTIO_MSI_NO_VECTOR) 370 return NULL; 371 372 return pci_irq_get_affinity(vp_dev->pci_dev, map[index]); 373 } 374 375 #ifdef CONFIG_PM_SLEEP 376 static int virtio_pci_freeze(struct device *dev) 377 { 378 struct pci_dev *pci_dev = to_pci_dev(dev); 379 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 380 int ret; 381 382 ret = virtio_device_freeze(&vp_dev->vdev); 383 384 if (!ret) 385 pci_disable_device(pci_dev); 386 return ret; 387 } 388 389 static int virtio_pci_restore(struct device *dev) 390 { 391 struct pci_dev *pci_dev = to_pci_dev(dev); 392 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 393 int ret; 394 395 ret = pci_enable_device(pci_dev); 396 if (ret) 397 return ret; 398 399 pci_set_master(pci_dev); 400 return virtio_device_restore(&vp_dev->vdev); 401 } 402 403 static const struct dev_pm_ops virtio_pci_pm_ops = { 404 SET_SYSTEM_SLEEP_PM_OPS(virtio_pci_freeze, virtio_pci_restore) 405 }; 406 #endif 407 408 409 /* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */ 410 static const struct pci_device_id virtio_pci_id_table[] = { 411 { PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID) }, 412 { 0 } 413 }; 414 415 MODULE_DEVICE_TABLE(pci, virtio_pci_id_table); 416 417 static void virtio_pci_release_dev(struct device *_d) 418 { 419 struct virtio_device *vdev = dev_to_virtio(_d); 420 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 421 422 /* As struct device is a kobject, it's not safe to 423 * free the memory (including the reference counter itself) 424 * until it's release callback. */ 425 kfree(vp_dev); 426 } 427 428 static int virtio_pci_probe(struct pci_dev *pci_dev, 429 const struct pci_device_id *id) 430 { 431 struct virtio_pci_device *vp_dev; 432 int rc; 433 434 /* allocate our structure and fill it out */ 435 vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL); 436 if (!vp_dev) 437 return -ENOMEM; 438 439 pci_set_drvdata(pci_dev, vp_dev); 440 vp_dev->vdev.dev.parent = &pci_dev->dev; 441 vp_dev->vdev.dev.release = virtio_pci_release_dev; 442 vp_dev->pci_dev = pci_dev; 443 444 /* enable the device */ 445 rc = pci_enable_device(pci_dev); 446 if (rc) 447 goto err_enable_device; 448 449 if (force_legacy) { 450 rc = virtio_pci_legacy_probe(vp_dev); 451 /* Also try modern mode if we can't map BAR0 (no IO space). */ 452 if (rc == -ENODEV || rc == -ENOMEM) 453 rc = virtio_pci_modern_probe(vp_dev); 454 if (rc) 455 goto err_probe; 456 } else { 457 rc = virtio_pci_modern_probe(vp_dev); 458 if (rc == -ENODEV) 459 rc = virtio_pci_legacy_probe(vp_dev); 460 if (rc) 461 goto err_probe; 462 } 463 464 pci_set_master(pci_dev); 465 466 rc = register_virtio_device(&vp_dev->vdev); 467 if (rc) 468 goto err_register; 469 470 return 0; 471 472 err_register: 473 if (vp_dev->ioaddr) 474 virtio_pci_legacy_remove(vp_dev); 475 else 476 virtio_pci_modern_remove(vp_dev); 477 err_probe: 478 pci_disable_device(pci_dev); 479 err_enable_device: 480 kfree(vp_dev); 481 return rc; 482 } 483 484 static void virtio_pci_remove(struct pci_dev *pci_dev) 485 { 486 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 487 struct device *dev = get_device(&vp_dev->vdev.dev); 488 489 unregister_virtio_device(&vp_dev->vdev); 490 491 if (vp_dev->ioaddr) 492 virtio_pci_legacy_remove(vp_dev); 493 else 494 virtio_pci_modern_remove(vp_dev); 495 496 pci_disable_device(pci_dev); 497 put_device(dev); 498 } 499 500 static struct pci_driver virtio_pci_driver = { 501 .name = "virtio-pci", 502 .id_table = virtio_pci_id_table, 503 .probe = virtio_pci_probe, 504 .remove = virtio_pci_remove, 505 #ifdef CONFIG_PM_SLEEP 506 .driver.pm = &virtio_pci_pm_ops, 507 #endif 508 }; 509 510 module_pci_driver(virtio_pci_driver); 511 512 MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>"); 513 MODULE_DESCRIPTION("virtio-pci"); 514 MODULE_LICENSE("GPL"); 515 MODULE_VERSION("1"); 516