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