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 dev->config->set_status(dev, dev->config->get_status(dev) | status); 165 } 166 EXPORT_SYMBOL_GPL(virtio_add_status); 167 168 int virtio_finalize_features(struct virtio_device *dev) 169 { 170 int ret = dev->config->finalize_features(dev); 171 unsigned status; 172 173 if (ret) 174 return ret; 175 176 if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) 177 return 0; 178 179 virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK); 180 status = dev->config->get_status(dev); 181 if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) { 182 dev_err(&dev->dev, "virtio: device refuses features: %x\n", 183 status); 184 return -ENODEV; 185 } 186 return 0; 187 } 188 EXPORT_SYMBOL_GPL(virtio_finalize_features); 189 190 static int virtio_dev_probe(struct device *_d) 191 { 192 int err, i; 193 struct virtio_device *dev = dev_to_virtio(_d); 194 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 195 u64 device_features; 196 u64 driver_features; 197 u64 driver_features_legacy; 198 199 /* We have a driver! */ 200 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER); 201 202 /* Figure out what features the device supports. */ 203 device_features = dev->config->get_features(dev); 204 205 /* Figure out what features the driver supports. */ 206 driver_features = 0; 207 for (i = 0; i < drv->feature_table_size; i++) { 208 unsigned int f = drv->feature_table[i]; 209 BUG_ON(f >= 64); 210 driver_features |= (1ULL << f); 211 } 212 213 /* Some drivers have a separate feature table for virtio v1.0 */ 214 if (drv->feature_table_legacy) { 215 driver_features_legacy = 0; 216 for (i = 0; i < drv->feature_table_size_legacy; i++) { 217 unsigned int f = drv->feature_table_legacy[i]; 218 BUG_ON(f >= 64); 219 driver_features_legacy |= (1ULL << f); 220 } 221 } else { 222 driver_features_legacy = driver_features; 223 } 224 225 if (device_features & (1ULL << VIRTIO_F_VERSION_1)) 226 dev->features = driver_features & device_features; 227 else 228 dev->features = driver_features_legacy & device_features; 229 230 /* Transport features always preserved to pass to finalize_features. */ 231 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) 232 if (device_features & (1ULL << i)) 233 __virtio_set_bit(dev, i); 234 235 if (drv->validate) { 236 err = drv->validate(dev); 237 if (err) 238 goto err; 239 } 240 241 err = virtio_finalize_features(dev); 242 if (err) 243 goto err; 244 245 err = drv->probe(dev); 246 if (err) 247 goto err; 248 249 /* If probe didn't do it, mark device DRIVER_OK ourselves. */ 250 if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK)) 251 virtio_device_ready(dev); 252 253 if (drv->scan) 254 drv->scan(dev); 255 256 virtio_config_enable(dev); 257 258 return 0; 259 err: 260 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); 261 return err; 262 263 } 264 265 static int virtio_dev_remove(struct device *_d) 266 { 267 struct virtio_device *dev = dev_to_virtio(_d); 268 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 269 270 virtio_config_disable(dev); 271 272 drv->remove(dev); 273 274 /* Driver should have reset device. */ 275 WARN_ON_ONCE(dev->config->get_status(dev)); 276 277 /* Acknowledge the device's existence again. */ 278 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 279 return 0; 280 } 281 282 static struct bus_type virtio_bus = { 283 .name = "virtio", 284 .match = virtio_dev_match, 285 .dev_groups = virtio_dev_groups, 286 .uevent = virtio_uevent, 287 .probe = virtio_dev_probe, 288 .remove = virtio_dev_remove, 289 }; 290 291 int register_virtio_driver(struct virtio_driver *driver) 292 { 293 /* Catch this early. */ 294 BUG_ON(driver->feature_table_size && !driver->feature_table); 295 driver->driver.bus = &virtio_bus; 296 return driver_register(&driver->driver); 297 } 298 EXPORT_SYMBOL_GPL(register_virtio_driver); 299 300 void unregister_virtio_driver(struct virtio_driver *driver) 301 { 302 driver_unregister(&driver->driver); 303 } 304 EXPORT_SYMBOL_GPL(unregister_virtio_driver); 305 306 int register_virtio_device(struct virtio_device *dev) 307 { 308 int err; 309 310 dev->dev.bus = &virtio_bus; 311 312 /* Assign a unique device index and hence name. */ 313 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL); 314 if (err < 0) 315 goto out; 316 317 dev->index = err; 318 dev_set_name(&dev->dev, "virtio%u", dev->index); 319 320 spin_lock_init(&dev->config_lock); 321 dev->config_enabled = false; 322 dev->config_change_pending = false; 323 324 /* We always start by resetting the device, in case a previous 325 * driver messed it up. This also tests that code path a little. */ 326 dev->config->reset(dev); 327 328 /* Acknowledge that we've seen the device. */ 329 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 330 331 INIT_LIST_HEAD(&dev->vqs); 332 333 /* device_register() causes the bus infrastructure to look for a 334 * matching driver. */ 335 err = device_register(&dev->dev); 336 out: 337 if (err) 338 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); 339 return err; 340 } 341 EXPORT_SYMBOL_GPL(register_virtio_device); 342 343 void unregister_virtio_device(struct virtio_device *dev) 344 { 345 int index = dev->index; /* save for after device release */ 346 347 device_unregister(&dev->dev); 348 ida_simple_remove(&virtio_index_ida, index); 349 } 350 EXPORT_SYMBOL_GPL(unregister_virtio_device); 351 352 #ifdef CONFIG_PM_SLEEP 353 int virtio_device_freeze(struct virtio_device *dev) 354 { 355 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 356 357 virtio_config_disable(dev); 358 359 dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED; 360 361 if (drv && drv->freeze) 362 return drv->freeze(dev); 363 364 return 0; 365 } 366 EXPORT_SYMBOL_GPL(virtio_device_freeze); 367 368 int virtio_device_restore(struct virtio_device *dev) 369 { 370 struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); 371 int ret; 372 373 /* We always start by resetting the device, in case a previous 374 * driver messed it up. */ 375 dev->config->reset(dev); 376 377 /* Acknowledge that we've seen the device. */ 378 virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 379 380 /* Maybe driver failed before freeze. 381 * Restore the failed status, for debugging. */ 382 if (dev->failed) 383 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); 384 385 if (!drv) 386 return 0; 387 388 /* We have a driver! */ 389 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER); 390 391 ret = virtio_finalize_features(dev); 392 if (ret) 393 goto err; 394 395 if (drv->restore) { 396 ret = drv->restore(dev); 397 if (ret) 398 goto err; 399 } 400 401 /* Finally, tell the device we're all set */ 402 virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); 403 404 virtio_config_enable(dev); 405 406 return 0; 407 408 err: 409 virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); 410 return ret; 411 } 412 EXPORT_SYMBOL_GPL(virtio_device_restore); 413 #endif 414 415 static int virtio_init(void) 416 { 417 if (bus_register(&virtio_bus) != 0) 418 panic("virtio bus registration failed"); 419 return 0; 420 } 421 422 static void __exit virtio_exit(void) 423 { 424 bus_unregister(&virtio_bus); 425 ida_destroy(&virtio_index_ida); 426 } 427 core_initcall(virtio_init); 428 module_exit(virtio_exit); 429 430 MODULE_LICENSE("GPL"); 431