1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/virtio.h> 3 #include <linux/spinlock.h> 4 #include <linux/virtio_config.h> 5 #include <linux/module.h> 6 #include <linux/idr.h> 7 #include <linux/of.h> 8 #include <uapi/linux/virtio_ids.h> 9 10 /* Unique numbering for virtio devices. */ 11 static DEFINE_IDA(virtio_index_ida); 12 13 static ssize_t device_show(struct device *_d, 14 struct device_attribute *attr, char *buf) 15 { 16 struct virtio_device *dev = dev_to_virtio(_d); 17 return sprintf(buf, "0x%04x\n", dev->id.device); 18 } 19 static DEVICE_ATTR_RO(device); 20 21 static ssize_t vendor_show(struct device *_d, 22 struct device_attribute *attr, char *buf) 23 { 24 struct virtio_device *dev = dev_to_virtio(_d); 25 return sprintf(buf, "0x%04x\n", dev->id.vendor); 26 } 27 static DEVICE_ATTR_RO(vendor); 28 29 static ssize_t status_show(struct device *_d, 30 struct device_attribute *attr, char *buf) 31 { 32 struct virtio_device *dev = dev_to_virtio(_d); 33 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev)); 34 } 35 static DEVICE_ATTR_RO(status); 36 37 static ssize_t modalias_show(struct device *_d, 38 struct device_attribute *attr, char *buf) 39 { 40 struct virtio_device *dev = dev_to_virtio(_d); 41 return sprintf(buf, "virtio:d%08Xv%08X\n", 42 dev->id.device, dev->id.vendor); 43 } 44 static DEVICE_ATTR_RO(modalias); 45 46 static ssize_t features_show(struct device *_d, 47 struct device_attribute *attr, char *buf) 48 { 49 struct virtio_device *dev = dev_to_virtio(_d); 50 unsigned int i; 51 ssize_t len = 0; 52 53 /* We actually represent this as a bitstring, as it could be 54 * arbitrary length in future. */ 55 for (i = 0; i < sizeof(dev->features)*8; i++) 56 len += sprintf(buf+len, "%c", 57 __virtio_test_bit(dev, i) ? '1' : '0'); 58 len += sprintf(buf+len, "\n"); 59 return len; 60 } 61 static DEVICE_ATTR_RO(features); 62 63 static struct attribute *virtio_dev_attrs[] = { 64 &dev_attr_device.attr, 65 &dev_attr_vendor.attr, 66 &dev_attr_status.attr, 67 &dev_attr_modalias.attr, 68 &dev_attr_features.attr, 69 NULL, 70 }; 71 ATTRIBUTE_GROUPS(virtio_dev); 72 73 static inline int virtio_id_match(const struct virtio_device *dev, 74 const struct virtio_device_id *id) 75 { 76 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID) 77 return 0; 78 79 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor; 80 } 81 82 /* This looks through all the IDs a driver claims to support. If any of them 83 * match, we return 1 and the kernel will call virtio_dev_probe(). */ 84 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr) 85 { 86 unsigned int i; 87 struct virtio_device *dev = dev_to_virtio(_dv); 88 const struct virtio_device_id *ids; 89 90 ids = drv_to_virtio(_dr)->id_table; 91 for (i = 0; ids[i].device; i++) 92 if (virtio_id_match(dev, &ids[i])) 93 return 1; 94 return 0; 95 } 96 97 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env) 98 { 99 struct virtio_device *dev = dev_to_virtio(_dv); 100 101 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X", 102 dev->id.device, dev->id.vendor); 103 } 104 105 void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 106 unsigned int fbit) 107 { 108 unsigned int i; 109 struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver); 110 111 for (i = 0; i < drv->feature_table_size; i++) 112 if (drv->feature_table[i] == fbit) 113 return; 114 115 if (drv->feature_table_legacy) { 116 for (i = 0; i < drv->feature_table_size_legacy; i++) 117 if (drv->feature_table_legacy[i] == fbit) 118 return; 119 } 120 121 BUG(); 122 } 123 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); 124 125 static void __virtio_config_changed(struct virtio_device *dev) 126 { 127 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 128 129 if (!dev->config_enabled) 130 dev->config_change_pending = true; 131 else if (drv && drv->config_changed) 132 drv->config_changed(dev); 133 } 134 135 void virtio_config_changed(struct virtio_device *dev) 136 { 137 unsigned long flags; 138 139 spin_lock_irqsave(&dev->config_lock, flags); 140 __virtio_config_changed(dev); 141 spin_unlock_irqrestore(&dev->config_lock, flags); 142 } 143 EXPORT_SYMBOL_GPL(virtio_config_changed); 144 145 static void virtio_config_disable(struct virtio_device *dev) 146 { 147 spin_lock_irq(&dev->config_lock); 148 dev->config_enabled = false; 149 spin_unlock_irq(&dev->config_lock); 150 } 151 152 static void virtio_config_enable(struct virtio_device *dev) 153 { 154 spin_lock_irq(&dev->config_lock); 155 dev->config_enabled = true; 156 if (dev->config_change_pending) 157 __virtio_config_changed(dev); 158 dev->config_change_pending = false; 159 spin_unlock_irq(&dev->config_lock); 160 } 161 162 void virtio_add_status(struct virtio_device *dev, unsigned int status) 163 { 164 might_sleep(); 165 dev->config->set_status(dev, dev->config->get_status(dev) | status); 166 } 167 EXPORT_SYMBOL_GPL(virtio_add_status); 168 169 int virtio_finalize_features(struct virtio_device *dev) 170 { 171 int ret = dev->config->finalize_features(dev); 172 unsigned status; 173 174 might_sleep(); 175 if (ret) 176 return ret; 177 178 ret = arch_has_restricted_virtio_memory_access(); 179 if (ret) { 180 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { 181 dev_warn(&dev->dev, 182 "device must provide VIRTIO_F_VERSION_1\n"); 183 return -ENODEV; 184 } 185 186 if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) { 187 dev_warn(&dev->dev, 188 "device must provide VIRTIO_F_ACCESS_PLATFORM\n"); 189 return -ENODEV; 190 } 191 } 192 193 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) 194 return 0; 195 196 virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK); 197 status = dev->config->get_status(dev); 198 if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) { 199 dev_err(&dev->dev, "virtio: device refuses features: %x\n", 200 status); 201 return -ENODEV; 202 } 203 return 0; 204 } 205 EXPORT_SYMBOL_GPL(virtio_finalize_features); 206 207 void virtio_reset_device(struct virtio_device *dev) 208 { 209 dev->config->reset(dev); 210 } 211 EXPORT_SYMBOL_GPL(virtio_reset_device); 212 213 static int virtio_dev_probe(struct device *_d) 214 { 215 int err, i; 216 struct virtio_device *dev = dev_to_virtio(_d); 217 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 218 u64 device_features; 219 u64 driver_features; 220 u64 driver_features_legacy; 221 222 /* We have a driver! */ 223 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER); 224 225 /* Figure out what features the device supports. */ 226 device_features = dev->config->get_features(dev); 227 228 /* Figure out what features the driver supports. */ 229 driver_features = 0; 230 for (i = 0; i < drv->feature_table_size; i++) { 231 unsigned int f = drv->feature_table[i]; 232 BUG_ON(f >= 64); 233 driver_features |= (1ULL << f); 234 } 235 236 /* Some drivers have a separate feature table for virtio v1.0 */ 237 if (drv->feature_table_legacy) { 238 driver_features_legacy = 0; 239 for (i = 0; i < drv->feature_table_size_legacy; i++) { 240 unsigned int f = drv->feature_table_legacy[i]; 241 BUG_ON(f >= 64); 242 driver_features_legacy |= (1ULL << f); 243 } 244 } else { 245 driver_features_legacy = driver_features; 246 } 247 248 /* 249 * Some devices detect legacy solely via F_VERSION_1. Write 250 * F_VERSION_1 to force LE config space accesses before FEATURES_OK for 251 * these when needed. 252 */ 253 if (drv->validate && !virtio_legacy_is_little_endian() 254 && device_features & BIT_ULL(VIRTIO_F_VERSION_1)) { 255 dev->features = BIT_ULL(VIRTIO_F_VERSION_1); 256 dev->config->finalize_features(dev); 257 } 258 259 if (device_features & (1ULL << VIRTIO_F_VERSION_1)) 260 dev->features = driver_features & device_features; 261 else 262 dev->features = driver_features_legacy & device_features; 263 264 /* Transport features always preserved to pass to finalize_features. */ 265 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) 266 if (device_features & (1ULL << i)) 267 __virtio_set_bit(dev, i); 268 269 if (drv->validate) { 270 err = drv->validate(dev); 271 if (err) 272 goto err; 273 } 274 275 err = virtio_finalize_features(dev); 276 if (err) 277 goto err; 278 279 err = drv->probe(dev); 280 if (err) 281 goto err; 282 283 /* If probe didn't do it, mark device DRIVER_OK ourselves. */ 284 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK)) 285 virtio_device_ready(dev); 286 287 if (drv->scan) 288 drv->scan(dev); 289 290 virtio_config_enable(dev); 291 292 return 0; 293 err: 294 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); 295 return err; 296 297 } 298 299 static void virtio_dev_remove(struct device *_d) 300 { 301 struct virtio_device *dev = dev_to_virtio(_d); 302 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 303 304 virtio_config_disable(dev); 305 306 drv->remove(dev); 307 308 /* Driver should have reset device. */ 309 WARN_ON_ONCE(dev->config->get_status(dev)); 310 311 /* Acknowledge the device's existence again. */ 312 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 313 314 of_node_put(dev->dev.of_node); 315 } 316 317 static struct bus_type virtio_bus = { 318 .name = "virtio", 319 .match = virtio_dev_match, 320 .dev_groups = virtio_dev_groups, 321 .uevent = virtio_uevent, 322 .probe = virtio_dev_probe, 323 .remove = virtio_dev_remove, 324 }; 325 326 int register_virtio_driver(struct virtio_driver *driver) 327 { 328 /* Catch this early. */ 329 BUG_ON(driver->feature_table_size && !driver->feature_table); 330 driver->driver.bus = &virtio_bus; 331 return driver_register(&driver->driver); 332 } 333 EXPORT_SYMBOL_GPL(register_virtio_driver); 334 335 void unregister_virtio_driver(struct virtio_driver *driver) 336 { 337 driver_unregister(&driver->driver); 338 } 339 EXPORT_SYMBOL_GPL(unregister_virtio_driver); 340 341 static int virtio_device_of_init(struct virtio_device *dev) 342 { 343 struct device_node *np, *pnode = dev_of_node(dev->dev.parent); 344 char compat[] = "virtio,deviceXXXXXXXX"; 345 int ret, count; 346 347 if (!pnode) 348 return 0; 349 350 count = of_get_available_child_count(pnode); 351 if (!count) 352 return 0; 353 354 /* There can be only 1 child node */ 355 if (WARN_ON(count > 1)) 356 return -EINVAL; 357 358 np = of_get_next_available_child(pnode, NULL); 359 if (WARN_ON(!np)) 360 return -ENODEV; 361 362 ret = snprintf(compat, sizeof(compat), "virtio,device%x", dev->id.device); 363 BUG_ON(ret >= sizeof(compat)); 364 365 /* 366 * On powerpc/pseries virtio devices are PCI devices so PCI 367 * vendor/device ids play the role of the "compatible" property. 368 * Simply don't init of_node in this case. 369 */ 370 if (!of_device_is_compatible(np, compat)) { 371 ret = 0; 372 goto out; 373 } 374 375 dev->dev.of_node = np; 376 return 0; 377 378 out: 379 of_node_put(np); 380 return ret; 381 } 382 383 /** 384 * register_virtio_device - register virtio device 385 * @dev : virtio device to be registered 386 * 387 * On error, the caller must call put_device on &@dev->dev (and not kfree), 388 * as another code path may have obtained a reference to @dev. 389 * 390 * Returns: 0 on suceess, -error on failure 391 */ 392 int register_virtio_device(struct virtio_device *dev) 393 { 394 int err; 395 396 dev->dev.bus = &virtio_bus; 397 device_initialize(&dev->dev); 398 399 /* Assign a unique device index and hence name. */ 400 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL); 401 if (err < 0) 402 goto out; 403 404 dev->index = err; 405 dev_set_name(&dev->dev, "virtio%u", dev->index); 406 407 err = virtio_device_of_init(dev); 408 if (err) 409 goto out_ida_remove; 410 411 spin_lock_init(&dev->config_lock); 412 dev->config_enabled = false; 413 dev->config_change_pending = false; 414 415 /* We always start by resetting the device, in case a previous 416 * driver messed it up. This also tests that code path a little. */ 417 dev->config->reset(dev); 418 419 /* Acknowledge that we've seen the device. */ 420 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 421 422 INIT_LIST_HEAD(&dev->vqs); 423 spin_lock_init(&dev->vqs_list_lock); 424 425 /* 426 * device_add() causes the bus infrastructure to look for a matching 427 * driver. 428 */ 429 err = device_add(&dev->dev); 430 if (err) 431 goto out_of_node_put; 432 433 return 0; 434 435 out_of_node_put: 436 of_node_put(dev->dev.of_node); 437 out_ida_remove: 438 ida_simple_remove(&virtio_index_ida, dev->index); 439 out: 440 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); 441 return err; 442 } 443 EXPORT_SYMBOL_GPL(register_virtio_device); 444 445 bool is_virtio_device(struct device *dev) 446 { 447 return dev->bus == &virtio_bus; 448 } 449 EXPORT_SYMBOL_GPL(is_virtio_device); 450 451 void unregister_virtio_device(struct virtio_device *dev) 452 { 453 int index = dev->index; /* save for after device release */ 454 455 device_unregister(&dev->dev); 456 ida_simple_remove(&virtio_index_ida, index); 457 } 458 EXPORT_SYMBOL_GPL(unregister_virtio_device); 459 460 #ifdef CONFIG_PM_SLEEP 461 int virtio_device_freeze(struct virtio_device *dev) 462 { 463 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 464 465 virtio_config_disable(dev); 466 467 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED; 468 469 if (drv && drv->freeze) 470 return drv->freeze(dev); 471 472 return 0; 473 } 474 EXPORT_SYMBOL_GPL(virtio_device_freeze); 475 476 int virtio_device_restore(struct virtio_device *dev) 477 { 478 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 479 int ret; 480 481 /* We always start by resetting the device, in case a previous 482 * driver messed it up. */ 483 dev->config->reset(dev); 484 485 /* Acknowledge that we've seen the device. */ 486 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 487 488 /* Maybe driver failed before freeze. 489 * Restore the failed status, for debugging. */ 490 if (dev->failed) 491 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); 492 493 if (!drv) 494 return 0; 495 496 /* We have a driver! */ 497 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER); 498 499 ret = virtio_finalize_features(dev); 500 if (ret) 501 goto err; 502 503 if (drv->restore) { 504 ret = drv->restore(dev); 505 if (ret) 506 goto err; 507 } 508 509 /* Finally, tell the device we're all set */ 510 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); 511 512 virtio_config_enable(dev); 513 514 return 0; 515 516 err: 517 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); 518 return ret; 519 } 520 EXPORT_SYMBOL_GPL(virtio_device_restore); 521 #endif 522 523 static int virtio_init(void) 524 { 525 if (bus_register(&virtio_bus) != 0) 526 panic("virtio bus registration failed"); 527 return 0; 528 } 529 530 static void __exit virtio_exit(void) 531 { 532 bus_unregister(&virtio_bus); 533 ida_destroy(&virtio_index_ida); 534 } 535 core_initcall(virtio_init); 536 module_exit(virtio_exit); 537 538 MODULE_LICENSE("GPL"); 539