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