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 /* wait for pending irq handlers */ 23 void vp_synchronize_vectors(struct virtio_device *vdev) 24 { 25 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 26 int i; 27 28 if (vp_dev->intx_enabled) 29 synchronize_irq(vp_dev->pci_dev->irq); 30 31 for (i = 0; i < vp_dev->msix_vectors; ++i) 32 synchronize_irq(vp_dev->msix_entries[i].vector); 33 } 34 35 /* the notify function used when creating a virt queue */ 36 bool vp_notify(struct virtqueue *vq) 37 { 38 /* we write the queue's selector into the notification register to 39 * signal the other end */ 40 iowrite16(vq->index, (void __iomem *)vq->priv); 41 return true; 42 } 43 44 /* Handle a configuration change: Tell driver if it wants to know. */ 45 static irqreturn_t vp_config_changed(int irq, void *opaque) 46 { 47 struct virtio_pci_device *vp_dev = opaque; 48 49 virtio_config_changed(&vp_dev->vdev); 50 return IRQ_HANDLED; 51 } 52 53 /* Notify all virtqueues on an interrupt. */ 54 static irqreturn_t vp_vring_interrupt(int irq, void *opaque) 55 { 56 struct virtio_pci_device *vp_dev = opaque; 57 struct virtio_pci_vq_info *info; 58 irqreturn_t ret = IRQ_NONE; 59 unsigned long flags; 60 61 spin_lock_irqsave(&vp_dev->lock, flags); 62 list_for_each_entry(info, &vp_dev->virtqueues, node) { 63 if (vring_interrupt(irq, info->vq) == IRQ_HANDLED) 64 ret = IRQ_HANDLED; 65 } 66 spin_unlock_irqrestore(&vp_dev->lock, flags); 67 68 return ret; 69 } 70 71 /* A small wrapper to also acknowledge the interrupt when it's handled. 72 * I really need an EIO hook for the vring so I can ack the interrupt once we 73 * know that we'll be handling the IRQ but before we invoke the callback since 74 * the callback may notify the host which results in the host attempting to 75 * raise an interrupt that we would then mask once we acknowledged the 76 * interrupt. */ 77 static irqreturn_t vp_interrupt(int irq, void *opaque) 78 { 79 struct virtio_pci_device *vp_dev = opaque; 80 u8 isr; 81 82 /* reading the ISR has the effect of also clearing it so it's very 83 * important to save off the value. */ 84 isr = ioread8(vp_dev->isr); 85 86 /* It's definitely not us if the ISR was not high */ 87 if (!isr) 88 return IRQ_NONE; 89 90 /* Configuration change? Tell driver if it wants to know. */ 91 if (isr & VIRTIO_PCI_ISR_CONFIG) 92 vp_config_changed(irq, opaque); 93 94 return vp_vring_interrupt(irq, opaque); 95 } 96 97 static void vp_free_vectors(struct virtio_device *vdev) 98 { 99 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 100 int i; 101 102 if (vp_dev->intx_enabled) { 103 free_irq(vp_dev->pci_dev->irq, vp_dev); 104 vp_dev->intx_enabled = 0; 105 } 106 107 for (i = 0; i < vp_dev->msix_used_vectors; ++i) 108 free_irq(vp_dev->msix_entries[i].vector, vp_dev); 109 110 for (i = 0; i < vp_dev->msix_vectors; i++) 111 if (vp_dev->msix_affinity_masks[i]) 112 free_cpumask_var(vp_dev->msix_affinity_masks[i]); 113 114 if (vp_dev->msix_enabled) { 115 /* Disable the vector used for configuration */ 116 vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR); 117 118 pci_disable_msix(vp_dev->pci_dev); 119 vp_dev->msix_enabled = 0; 120 } 121 122 vp_dev->msix_vectors = 0; 123 vp_dev->msix_used_vectors = 0; 124 kfree(vp_dev->msix_names); 125 vp_dev->msix_names = NULL; 126 kfree(vp_dev->msix_entries); 127 vp_dev->msix_entries = NULL; 128 kfree(vp_dev->msix_affinity_masks); 129 vp_dev->msix_affinity_masks = NULL; 130 } 131 132 static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors, 133 bool per_vq_vectors) 134 { 135 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 136 const char *name = dev_name(&vp_dev->vdev.dev); 137 unsigned i, v; 138 int err = -ENOMEM; 139 140 vp_dev->msix_vectors = nvectors; 141 142 vp_dev->msix_entries = kmalloc(nvectors * sizeof *vp_dev->msix_entries, 143 GFP_KERNEL); 144 if (!vp_dev->msix_entries) 145 goto error; 146 vp_dev->msix_names = kmalloc(nvectors * sizeof *vp_dev->msix_names, 147 GFP_KERNEL); 148 if (!vp_dev->msix_names) 149 goto error; 150 vp_dev->msix_affinity_masks 151 = kzalloc(nvectors * sizeof *vp_dev->msix_affinity_masks, 152 GFP_KERNEL); 153 if (!vp_dev->msix_affinity_masks) 154 goto error; 155 for (i = 0; i < nvectors; ++i) 156 if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i], 157 GFP_KERNEL)) 158 goto error; 159 160 for (i = 0; i < nvectors; ++i) 161 vp_dev->msix_entries[i].entry = i; 162 163 err = pci_enable_msix_exact(vp_dev->pci_dev, 164 vp_dev->msix_entries, nvectors); 165 if (err) 166 goto error; 167 vp_dev->msix_enabled = 1; 168 169 /* Set the vector used for configuration */ 170 v = vp_dev->msix_used_vectors; 171 snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, 172 "%s-config", name); 173 err = request_irq(vp_dev->msix_entries[v].vector, 174 vp_config_changed, 0, vp_dev->msix_names[v], 175 vp_dev); 176 if (err) 177 goto error; 178 ++vp_dev->msix_used_vectors; 179 180 v = vp_dev->config_vector(vp_dev, v); 181 /* Verify we had enough resources to assign the vector */ 182 if (v == VIRTIO_MSI_NO_VECTOR) { 183 err = -EBUSY; 184 goto error; 185 } 186 187 if (!per_vq_vectors) { 188 /* Shared vector for all VQs */ 189 v = vp_dev->msix_used_vectors; 190 snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, 191 "%s-virtqueues", name); 192 err = request_irq(vp_dev->msix_entries[v].vector, 193 vp_vring_interrupt, 0, vp_dev->msix_names[v], 194 vp_dev); 195 if (err) 196 goto error; 197 ++vp_dev->msix_used_vectors; 198 } 199 return 0; 200 error: 201 vp_free_vectors(vdev); 202 return err; 203 } 204 205 static int vp_request_intx(struct virtio_device *vdev) 206 { 207 int err; 208 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 209 210 err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, 211 IRQF_SHARED, dev_name(&vdev->dev), vp_dev); 212 if (!err) 213 vp_dev->intx_enabled = 1; 214 return err; 215 } 216 217 static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index, 218 void (*callback)(struct virtqueue *vq), 219 const char *name, 220 u16 msix_vec) 221 { 222 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 223 struct virtio_pci_vq_info *info = kmalloc(sizeof *info, GFP_KERNEL); 224 struct virtqueue *vq; 225 unsigned long flags; 226 227 /* fill out our structure that represents an active queue */ 228 if (!info) 229 return ERR_PTR(-ENOMEM); 230 231 vq = vp_dev->setup_vq(vp_dev, info, index, callback, name, msix_vec); 232 if (IS_ERR(vq)) 233 goto out_info; 234 235 info->vq = vq; 236 if (callback) { 237 spin_lock_irqsave(&vp_dev->lock, flags); 238 list_add(&info->node, &vp_dev->virtqueues); 239 spin_unlock_irqrestore(&vp_dev->lock, flags); 240 } else { 241 INIT_LIST_HEAD(&info->node); 242 } 243 244 vp_dev->vqs[index] = info; 245 return vq; 246 247 out_info: 248 kfree(info); 249 return vq; 250 } 251 252 static void vp_del_vq(struct virtqueue *vq) 253 { 254 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); 255 struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index]; 256 unsigned long flags; 257 258 spin_lock_irqsave(&vp_dev->lock, flags); 259 list_del(&info->node); 260 spin_unlock_irqrestore(&vp_dev->lock, flags); 261 262 vp_dev->del_vq(info); 263 kfree(info); 264 } 265 266 /* the config->del_vqs() implementation */ 267 void vp_del_vqs(struct virtio_device *vdev) 268 { 269 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 270 struct virtqueue *vq, *n; 271 struct virtio_pci_vq_info *info; 272 273 list_for_each_entry_safe(vq, n, &vdev->vqs, list) { 274 info = vp_dev->vqs[vq->index]; 275 if (vp_dev->per_vq_vectors && 276 info->msix_vector != VIRTIO_MSI_NO_VECTOR) 277 free_irq(vp_dev->msix_entries[info->msix_vector].vector, 278 vq); 279 vp_del_vq(vq); 280 } 281 vp_dev->per_vq_vectors = false; 282 283 vp_free_vectors(vdev); 284 kfree(vp_dev->vqs); 285 vp_dev->vqs = NULL; 286 } 287 288 static int vp_try_to_find_vqs(struct virtio_device *vdev, unsigned nvqs, 289 struct virtqueue *vqs[], 290 vq_callback_t *callbacks[], 291 const char *names[], 292 bool use_msix, 293 bool per_vq_vectors) 294 { 295 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 296 u16 msix_vec; 297 int i, err, nvectors, allocated_vectors; 298 299 vp_dev->vqs = kmalloc(nvqs * sizeof *vp_dev->vqs, GFP_KERNEL); 300 if (!vp_dev->vqs) 301 return -ENOMEM; 302 303 if (!use_msix) { 304 /* Old style: one normal interrupt for change and all vqs. */ 305 err = vp_request_intx(vdev); 306 if (err) 307 goto error_find; 308 } else { 309 if (per_vq_vectors) { 310 /* Best option: one for change interrupt, one per vq. */ 311 nvectors = 1; 312 for (i = 0; i < nvqs; ++i) 313 if (callbacks[i]) 314 ++nvectors; 315 } else { 316 /* Second best: one for change, shared for all vqs. */ 317 nvectors = 2; 318 } 319 320 err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors); 321 if (err) 322 goto error_find; 323 } 324 325 vp_dev->per_vq_vectors = per_vq_vectors; 326 allocated_vectors = vp_dev->msix_used_vectors; 327 for (i = 0; i < nvqs; ++i) { 328 if (!names[i]) { 329 vqs[i] = NULL; 330 continue; 331 } else if (!callbacks[i] || !vp_dev->msix_enabled) 332 msix_vec = VIRTIO_MSI_NO_VECTOR; 333 else if (vp_dev->per_vq_vectors) 334 msix_vec = allocated_vectors++; 335 else 336 msix_vec = VP_MSIX_VQ_VECTOR; 337 vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i], msix_vec); 338 if (IS_ERR(vqs[i])) { 339 err = PTR_ERR(vqs[i]); 340 goto error_find; 341 } 342 343 if (!vp_dev->per_vq_vectors || msix_vec == VIRTIO_MSI_NO_VECTOR) 344 continue; 345 346 /* allocate per-vq irq if available and necessary */ 347 snprintf(vp_dev->msix_names[msix_vec], 348 sizeof *vp_dev->msix_names, 349 "%s-%s", 350 dev_name(&vp_dev->vdev.dev), names[i]); 351 err = request_irq(vp_dev->msix_entries[msix_vec].vector, 352 vring_interrupt, 0, 353 vp_dev->msix_names[msix_vec], 354 vqs[i]); 355 if (err) { 356 vp_del_vq(vqs[i]); 357 goto error_find; 358 } 359 } 360 return 0; 361 362 error_find: 363 vp_del_vqs(vdev); 364 return err; 365 } 366 367 /* the config->find_vqs() implementation */ 368 int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, 369 struct virtqueue *vqs[], 370 vq_callback_t *callbacks[], 371 const char *names[]) 372 { 373 int err; 374 375 /* Try MSI-X with one vector per queue. */ 376 err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, true, true); 377 if (!err) 378 return 0; 379 /* Fallback: MSI-X with one vector for config, one shared for queues. */ 380 err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, 381 true, false); 382 if (!err) 383 return 0; 384 /* Finally fall back to regular interrupts. */ 385 return vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, 386 false, false); 387 } 388 389 const char *vp_bus_name(struct virtio_device *vdev) 390 { 391 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 392 393 return pci_name(vp_dev->pci_dev); 394 } 395 396 /* Setup the affinity for a virtqueue: 397 * - force the affinity for per vq vector 398 * - OR over all affinities for shared MSI 399 * - ignore the affinity request if we're using INTX 400 */ 401 int vp_set_vq_affinity(struct virtqueue *vq, int cpu) 402 { 403 struct virtio_device *vdev = vq->vdev; 404 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 405 struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index]; 406 struct cpumask *mask; 407 unsigned int irq; 408 409 if (!vq->callback) 410 return -EINVAL; 411 412 if (vp_dev->msix_enabled) { 413 mask = vp_dev->msix_affinity_masks[info->msix_vector]; 414 irq = vp_dev->msix_entries[info->msix_vector].vector; 415 if (cpu == -1) 416 irq_set_affinity_hint(irq, NULL); 417 else { 418 cpumask_set_cpu(cpu, mask); 419 irq_set_affinity_hint(irq, mask); 420 } 421 } 422 return 0; 423 } 424 425 #ifdef CONFIG_PM_SLEEP 426 static int virtio_pci_freeze(struct device *dev) 427 { 428 struct pci_dev *pci_dev = to_pci_dev(dev); 429 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 430 int ret; 431 432 ret = virtio_device_freeze(&vp_dev->vdev); 433 434 if (!ret) 435 pci_disable_device(pci_dev); 436 return ret; 437 } 438 439 static int virtio_pci_restore(struct device *dev) 440 { 441 struct pci_dev *pci_dev = to_pci_dev(dev); 442 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); 443 int ret; 444 445 ret = pci_enable_device(pci_dev); 446 if (ret) 447 return ret; 448 449 pci_set_master(pci_dev); 450 return virtio_device_restore(&vp_dev->vdev); 451 } 452 453 static const struct dev_pm_ops virtio_pci_pm_ops = { 454 SET_SYSTEM_SLEEP_PM_OPS(virtio_pci_freeze, virtio_pci_restore) 455 }; 456 #endif 457 458 459 /* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */ 460 static const struct pci_device_id virtio_pci_id_table[] = { 461 { PCI_DEVICE(0x1af4, PCI_ANY_ID) }, 462 { 0 } 463 }; 464 465 MODULE_DEVICE_TABLE(pci, virtio_pci_id_table); 466 467 static int virtio_pci_probe(struct pci_dev *pci_dev, 468 const struct pci_device_id *id) 469 { 470 return virtio_pci_legacy_probe(pci_dev, id); 471 } 472 473 static void virtio_pci_remove(struct pci_dev *pci_dev) 474 { 475 virtio_pci_legacy_remove(pci_dev); 476 } 477 478 static struct pci_driver virtio_pci_driver = { 479 .name = "virtio-pci", 480 .id_table = virtio_pci_id_table, 481 .probe = virtio_pci_probe, 482 .remove = virtio_pci_remove, 483 #ifdef CONFIG_PM_SLEEP 484 .driver.pm = &virtio_pci_pm_ops, 485 #endif 486 }; 487 488 module_pci_driver(virtio_pci_driver); 489 490 MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>"); 491 MODULE_DESCRIPTION("virtio-pci"); 492 MODULE_LICENSE("GPL"); 493 MODULE_VERSION("1"); 494