1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Mediated device Core Driver 4 * 5 * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved. 6 * Author: Neo Jia <cjia@nvidia.com> 7 * Kirti Wankhede <kwankhede@nvidia.com> 8 */ 9 10 #include <linux/module.h> 11 #include <linux/device.h> 12 #include <linux/slab.h> 13 #include <linux/uuid.h> 14 #include <linux/sysfs.h> 15 #include <linux/mdev.h> 16 17 #include "mdev_private.h" 18 19 #define DRIVER_VERSION "0.1" 20 #define DRIVER_AUTHOR "NVIDIA Corporation" 21 #define DRIVER_DESC "Mediated device Core Driver" 22 23 static LIST_HEAD(parent_list); 24 static DEFINE_MUTEX(parent_list_lock); 25 static struct class_compat *mdev_bus_compat_class; 26 27 static LIST_HEAD(mdev_list); 28 static DEFINE_MUTEX(mdev_list_lock); 29 30 struct device *mdev_parent_dev(struct mdev_device *mdev) 31 { 32 return mdev->parent->dev; 33 } 34 EXPORT_SYMBOL(mdev_parent_dev); 35 36 void *mdev_get_drvdata(struct mdev_device *mdev) 37 { 38 return mdev->driver_data; 39 } 40 EXPORT_SYMBOL(mdev_get_drvdata); 41 42 void mdev_set_drvdata(struct mdev_device *mdev, void *data) 43 { 44 mdev->driver_data = data; 45 } 46 EXPORT_SYMBOL(mdev_set_drvdata); 47 48 struct device *mdev_dev(struct mdev_device *mdev) 49 { 50 return &mdev->dev; 51 } 52 EXPORT_SYMBOL(mdev_dev); 53 54 struct mdev_device *mdev_from_dev(struct device *dev) 55 { 56 return dev_is_mdev(dev) ? to_mdev_device(dev) : NULL; 57 } 58 EXPORT_SYMBOL(mdev_from_dev); 59 60 const guid_t *mdev_uuid(struct mdev_device *mdev) 61 { 62 return &mdev->uuid; 63 } 64 EXPORT_SYMBOL(mdev_uuid); 65 66 /* Should be called holding parent_list_lock */ 67 static struct mdev_parent *__find_parent_device(struct device *dev) 68 { 69 struct mdev_parent *parent; 70 71 list_for_each_entry(parent, &parent_list, next) { 72 if (parent->dev == dev) 73 return parent; 74 } 75 return NULL; 76 } 77 78 static void mdev_release_parent(struct kref *kref) 79 { 80 struct mdev_parent *parent = container_of(kref, struct mdev_parent, 81 ref); 82 struct device *dev = parent->dev; 83 84 kfree(parent); 85 put_device(dev); 86 } 87 88 static struct mdev_parent *mdev_get_parent(struct mdev_parent *parent) 89 { 90 if (parent) 91 kref_get(&parent->ref); 92 93 return parent; 94 } 95 96 static void mdev_put_parent(struct mdev_parent *parent) 97 { 98 if (parent) 99 kref_put(&parent->ref, mdev_release_parent); 100 } 101 102 /* Caller must hold parent unreg_sem read or write lock */ 103 static void mdev_device_remove_common(struct mdev_device *mdev) 104 { 105 struct mdev_parent *parent; 106 struct mdev_type *type; 107 int ret; 108 109 type = to_mdev_type(mdev->type_kobj); 110 mdev_remove_sysfs_files(&mdev->dev, type); 111 device_del(&mdev->dev); 112 parent = mdev->parent; 113 lockdep_assert_held(&parent->unreg_sem); 114 ret = parent->ops->remove(mdev); 115 if (ret) 116 dev_err(&mdev->dev, "Remove failed: err=%d\n", ret); 117 118 /* Balances with device_initialize() */ 119 put_device(&mdev->dev); 120 mdev_put_parent(parent); 121 } 122 123 static int mdev_device_remove_cb(struct device *dev, void *data) 124 { 125 if (dev_is_mdev(dev)) { 126 struct mdev_device *mdev; 127 128 mdev = to_mdev_device(dev); 129 mdev_device_remove_common(mdev); 130 } 131 return 0; 132 } 133 134 /* 135 * mdev_register_device : Register a device 136 * @dev: device structure representing parent device. 137 * @ops: Parent device operation structure to be registered. 138 * 139 * Add device to list of registered parent devices. 140 * Returns a negative value on error, otherwise 0. 141 */ 142 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops) 143 { 144 int ret; 145 struct mdev_parent *parent; 146 char *env_string = "MDEV_STATE=registered"; 147 char *envp[] = { env_string, NULL }; 148 149 /* check for mandatory ops */ 150 if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups) 151 return -EINVAL; 152 153 dev = get_device(dev); 154 if (!dev) 155 return -EINVAL; 156 157 mutex_lock(&parent_list_lock); 158 159 /* Check for duplicate */ 160 parent = __find_parent_device(dev); 161 if (parent) { 162 parent = NULL; 163 ret = -EEXIST; 164 goto add_dev_err; 165 } 166 167 parent = kzalloc(sizeof(*parent), GFP_KERNEL); 168 if (!parent) { 169 ret = -ENOMEM; 170 goto add_dev_err; 171 } 172 173 kref_init(&parent->ref); 174 init_rwsem(&parent->unreg_sem); 175 176 parent->dev = dev; 177 parent->ops = ops; 178 179 if (!mdev_bus_compat_class) { 180 mdev_bus_compat_class = class_compat_register("mdev_bus"); 181 if (!mdev_bus_compat_class) { 182 ret = -ENOMEM; 183 goto add_dev_err; 184 } 185 } 186 187 ret = parent_create_sysfs_files(parent); 188 if (ret) 189 goto add_dev_err; 190 191 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL); 192 if (ret) 193 dev_warn(dev, "Failed to create compatibility class link\n"); 194 195 list_add(&parent->next, &parent_list); 196 mutex_unlock(&parent_list_lock); 197 198 dev_info(dev, "MDEV: Registered\n"); 199 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); 200 201 return 0; 202 203 add_dev_err: 204 mutex_unlock(&parent_list_lock); 205 if (parent) 206 mdev_put_parent(parent); 207 else 208 put_device(dev); 209 return ret; 210 } 211 EXPORT_SYMBOL(mdev_register_device); 212 213 /* 214 * mdev_unregister_device : Unregister a parent device 215 * @dev: device structure representing parent device. 216 * 217 * Remove device from list of registered parent devices. Give a chance to free 218 * existing mediated devices for given device. 219 */ 220 221 void mdev_unregister_device(struct device *dev) 222 { 223 struct mdev_parent *parent; 224 char *env_string = "MDEV_STATE=unregistered"; 225 char *envp[] = { env_string, NULL }; 226 227 mutex_lock(&parent_list_lock); 228 parent = __find_parent_device(dev); 229 230 if (!parent) { 231 mutex_unlock(&parent_list_lock); 232 return; 233 } 234 dev_info(dev, "MDEV: Unregistering\n"); 235 236 list_del(&parent->next); 237 mutex_unlock(&parent_list_lock); 238 239 down_write(&parent->unreg_sem); 240 241 class_compat_remove_link(mdev_bus_compat_class, dev, NULL); 242 243 device_for_each_child(dev, NULL, mdev_device_remove_cb); 244 245 parent_remove_sysfs_files(parent); 246 up_write(&parent->unreg_sem); 247 248 mdev_put_parent(parent); 249 250 /* We still have the caller's reference to use for the uevent */ 251 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); 252 } 253 EXPORT_SYMBOL(mdev_unregister_device); 254 255 static void mdev_device_free(struct mdev_device *mdev) 256 { 257 mutex_lock(&mdev_list_lock); 258 list_del(&mdev->next); 259 mutex_unlock(&mdev_list_lock); 260 261 dev_dbg(&mdev->dev, "MDEV: destroying\n"); 262 kfree(mdev); 263 } 264 265 static void mdev_device_release(struct device *dev) 266 { 267 struct mdev_device *mdev = to_mdev_device(dev); 268 269 mdev_device_free(mdev); 270 } 271 272 int mdev_device_create(struct kobject *kobj, 273 struct device *dev, const guid_t *uuid) 274 { 275 int ret; 276 struct mdev_device *mdev, *tmp; 277 struct mdev_parent *parent; 278 struct mdev_type *type = to_mdev_type(kobj); 279 280 parent = mdev_get_parent(type->parent); 281 if (!parent) 282 return -EINVAL; 283 284 mutex_lock(&mdev_list_lock); 285 286 /* Check for duplicate */ 287 list_for_each_entry(tmp, &mdev_list, next) { 288 if (guid_equal(&tmp->uuid, uuid)) { 289 mutex_unlock(&mdev_list_lock); 290 ret = -EEXIST; 291 goto mdev_fail; 292 } 293 } 294 295 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); 296 if (!mdev) { 297 mutex_unlock(&mdev_list_lock); 298 ret = -ENOMEM; 299 goto mdev_fail; 300 } 301 302 guid_copy(&mdev->uuid, uuid); 303 list_add(&mdev->next, &mdev_list); 304 mutex_unlock(&mdev_list_lock); 305 306 mdev->parent = parent; 307 308 /* Check if parent unregistration has started */ 309 if (!down_read_trylock(&parent->unreg_sem)) { 310 mdev_device_free(mdev); 311 ret = -ENODEV; 312 goto mdev_fail; 313 } 314 315 device_initialize(&mdev->dev); 316 mdev->dev.parent = dev; 317 mdev->dev.bus = &mdev_bus_type; 318 mdev->dev.release = mdev_device_release; 319 dev_set_name(&mdev->dev, "%pUl", uuid); 320 mdev->dev.groups = parent->ops->mdev_attr_groups; 321 mdev->type_kobj = kobj; 322 323 ret = parent->ops->create(kobj, mdev); 324 if (ret) 325 goto ops_create_fail; 326 327 ret = device_add(&mdev->dev); 328 if (ret) 329 goto add_fail; 330 331 ret = mdev_create_sysfs_files(&mdev->dev, type); 332 if (ret) 333 goto sysfs_fail; 334 335 mdev->active = true; 336 dev_dbg(&mdev->dev, "MDEV: created\n"); 337 up_read(&parent->unreg_sem); 338 339 return 0; 340 341 sysfs_fail: 342 device_del(&mdev->dev); 343 add_fail: 344 parent->ops->remove(mdev); 345 ops_create_fail: 346 up_read(&parent->unreg_sem); 347 put_device(&mdev->dev); 348 mdev_fail: 349 mdev_put_parent(parent); 350 return ret; 351 } 352 353 int mdev_device_remove(struct device *dev) 354 { 355 struct mdev_device *mdev, *tmp; 356 struct mdev_parent *parent; 357 358 mdev = to_mdev_device(dev); 359 360 mutex_lock(&mdev_list_lock); 361 list_for_each_entry(tmp, &mdev_list, next) { 362 if (tmp == mdev) 363 break; 364 } 365 366 if (tmp != mdev) { 367 mutex_unlock(&mdev_list_lock); 368 return -ENODEV; 369 } 370 371 if (!mdev->active) { 372 mutex_unlock(&mdev_list_lock); 373 return -EAGAIN; 374 } 375 376 mdev->active = false; 377 mutex_unlock(&mdev_list_lock); 378 379 parent = mdev->parent; 380 /* Check if parent unregistration has started */ 381 if (!down_read_trylock(&parent->unreg_sem)) 382 return -ENODEV; 383 384 mdev_device_remove_common(mdev); 385 up_read(&parent->unreg_sem); 386 return 0; 387 } 388 389 int mdev_set_iommu_device(struct device *dev, struct device *iommu_device) 390 { 391 struct mdev_device *mdev = to_mdev_device(dev); 392 393 mdev->iommu_device = iommu_device; 394 395 return 0; 396 } 397 EXPORT_SYMBOL(mdev_set_iommu_device); 398 399 struct device *mdev_get_iommu_device(struct device *dev) 400 { 401 struct mdev_device *mdev = to_mdev_device(dev); 402 403 return mdev->iommu_device; 404 } 405 EXPORT_SYMBOL(mdev_get_iommu_device); 406 407 static int __init mdev_init(void) 408 { 409 return mdev_bus_register(); 410 } 411 412 static void __exit mdev_exit(void) 413 { 414 if (mdev_bus_compat_class) 415 class_compat_unregister(mdev_bus_compat_class); 416 417 mdev_bus_unregister(); 418 } 419 420 module_init(mdev_init) 421 module_exit(mdev_exit) 422 423 MODULE_VERSION(DRIVER_VERSION); 424 MODULE_LICENSE("GPL v2"); 425 MODULE_AUTHOR(DRIVER_AUTHOR); 426 MODULE_DESCRIPTION(DRIVER_DESC); 427 MODULE_SOFTDEP("post: vfio_mdev"); 428