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->type->parent->dev; 33 } 34 EXPORT_SYMBOL(mdev_parent_dev); 35 36 /* 37 * Return the index in supported_type_groups that this mdev_device was created 38 * from. 39 */ 40 unsigned int mdev_get_type_group_id(struct mdev_device *mdev) 41 { 42 return mdev->type->type_group_id; 43 } 44 EXPORT_SYMBOL(mdev_get_type_group_id); 45 46 /* 47 * Used in mdev_type_attribute sysfs functions to return the index in the 48 * supported_type_groups that the sysfs is called from. 49 */ 50 unsigned int mtype_get_type_group_id(struct mdev_type *mtype) 51 { 52 return mtype->type_group_id; 53 } 54 EXPORT_SYMBOL(mtype_get_type_group_id); 55 56 /* 57 * Used in mdev_type_attribute sysfs functions to return the parent struct 58 * device 59 */ 60 struct device *mtype_get_parent_dev(struct mdev_type *mtype) 61 { 62 return mtype->parent->dev; 63 } 64 EXPORT_SYMBOL(mtype_get_parent_dev); 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 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 /* Caller must hold parent unreg_sem read or write lock */ 89 static void mdev_device_remove_common(struct mdev_device *mdev) 90 { 91 struct mdev_parent *parent = mdev->type->parent; 92 int ret; 93 94 mdev_remove_sysfs_files(mdev); 95 device_del(&mdev->dev); 96 lockdep_assert_held(&parent->unreg_sem); 97 if (parent->ops->remove) { 98 ret = parent->ops->remove(mdev); 99 if (ret) 100 dev_err(&mdev->dev, "Remove failed: err=%d\n", ret); 101 } 102 103 /* Balances with device_initialize() */ 104 put_device(&mdev->dev); 105 } 106 107 static int mdev_device_remove_cb(struct device *dev, void *data) 108 { 109 struct mdev_device *mdev = mdev_from_dev(dev); 110 111 if (mdev) 112 mdev_device_remove_common(mdev); 113 return 0; 114 } 115 116 /* 117 * mdev_register_device : Register a device 118 * @dev: device structure representing parent device. 119 * @ops: Parent device operation structure to be registered. 120 * 121 * Add device to list of registered parent devices. 122 * Returns a negative value on error, otherwise 0. 123 */ 124 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops) 125 { 126 int ret; 127 struct mdev_parent *parent; 128 char *env_string = "MDEV_STATE=registered"; 129 char *envp[] = { env_string, NULL }; 130 131 /* check for mandatory ops */ 132 if (!ops || !ops->supported_type_groups) 133 return -EINVAL; 134 if (!ops->device_driver && (!ops->create || !ops->remove)) 135 return -EINVAL; 136 137 dev = get_device(dev); 138 if (!dev) 139 return -EINVAL; 140 141 /* Not mandatory, but its absence could be a problem */ 142 if (!ops->request) 143 dev_info(dev, "Driver cannot be asked to release device\n"); 144 145 mutex_lock(&parent_list_lock); 146 147 /* Check for duplicate */ 148 parent = __find_parent_device(dev); 149 if (parent) { 150 parent = NULL; 151 ret = -EEXIST; 152 goto add_dev_err; 153 } 154 155 parent = kzalloc(sizeof(*parent), GFP_KERNEL); 156 if (!parent) { 157 ret = -ENOMEM; 158 goto add_dev_err; 159 } 160 161 kref_init(&parent->ref); 162 init_rwsem(&parent->unreg_sem); 163 164 parent->dev = dev; 165 parent->ops = ops; 166 167 if (!mdev_bus_compat_class) { 168 mdev_bus_compat_class = class_compat_register("mdev_bus"); 169 if (!mdev_bus_compat_class) { 170 ret = -ENOMEM; 171 goto add_dev_err; 172 } 173 } 174 175 ret = parent_create_sysfs_files(parent); 176 if (ret) 177 goto add_dev_err; 178 179 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL); 180 if (ret) 181 dev_warn(dev, "Failed to create compatibility class link\n"); 182 183 list_add(&parent->next, &parent_list); 184 mutex_unlock(&parent_list_lock); 185 186 dev_info(dev, "MDEV: Registered\n"); 187 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); 188 189 return 0; 190 191 add_dev_err: 192 mutex_unlock(&parent_list_lock); 193 if (parent) 194 mdev_put_parent(parent); 195 else 196 put_device(dev); 197 return ret; 198 } 199 EXPORT_SYMBOL(mdev_register_device); 200 201 /* 202 * mdev_unregister_device : Unregister a parent device 203 * @dev: device structure representing parent device. 204 * 205 * Remove device from list of registered parent devices. Give a chance to free 206 * existing mediated devices for given device. 207 */ 208 209 void mdev_unregister_device(struct device *dev) 210 { 211 struct mdev_parent *parent; 212 char *env_string = "MDEV_STATE=unregistered"; 213 char *envp[] = { env_string, NULL }; 214 215 mutex_lock(&parent_list_lock); 216 parent = __find_parent_device(dev); 217 218 if (!parent) { 219 mutex_unlock(&parent_list_lock); 220 return; 221 } 222 dev_info(dev, "MDEV: Unregistering\n"); 223 224 list_del(&parent->next); 225 mutex_unlock(&parent_list_lock); 226 227 down_write(&parent->unreg_sem); 228 229 class_compat_remove_link(mdev_bus_compat_class, dev, NULL); 230 231 device_for_each_child(dev, NULL, mdev_device_remove_cb); 232 233 parent_remove_sysfs_files(parent); 234 up_write(&parent->unreg_sem); 235 236 mdev_put_parent(parent); 237 238 /* We still have the caller's reference to use for the uevent */ 239 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); 240 } 241 EXPORT_SYMBOL(mdev_unregister_device); 242 243 static void mdev_device_release(struct device *dev) 244 { 245 struct mdev_device *mdev = to_mdev_device(dev); 246 247 /* Pairs with the get in mdev_device_create() */ 248 kobject_put(&mdev->type->kobj); 249 250 mutex_lock(&mdev_list_lock); 251 list_del(&mdev->next); 252 mutex_unlock(&mdev_list_lock); 253 254 dev_dbg(&mdev->dev, "MDEV: destroying\n"); 255 kfree(mdev); 256 } 257 258 int mdev_device_create(struct mdev_type *type, const guid_t *uuid) 259 { 260 int ret; 261 struct mdev_device *mdev, *tmp; 262 struct mdev_parent *parent = type->parent; 263 struct mdev_driver *drv = parent->ops->device_driver; 264 265 mutex_lock(&mdev_list_lock); 266 267 /* Check for duplicate */ 268 list_for_each_entry(tmp, &mdev_list, next) { 269 if (guid_equal(&tmp->uuid, uuid)) { 270 mutex_unlock(&mdev_list_lock); 271 return -EEXIST; 272 } 273 } 274 275 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); 276 if (!mdev) { 277 mutex_unlock(&mdev_list_lock); 278 return -ENOMEM; 279 } 280 281 device_initialize(&mdev->dev); 282 mdev->dev.parent = parent->dev; 283 mdev->dev.bus = &mdev_bus_type; 284 mdev->dev.release = mdev_device_release; 285 mdev->dev.groups = parent->ops->mdev_attr_groups; 286 mdev->type = type; 287 /* Pairs with the put in mdev_device_release() */ 288 kobject_get(&type->kobj); 289 290 guid_copy(&mdev->uuid, uuid); 291 list_add(&mdev->next, &mdev_list); 292 mutex_unlock(&mdev_list_lock); 293 294 ret = dev_set_name(&mdev->dev, "%pUl", uuid); 295 if (ret) 296 goto out_put_device; 297 298 /* Check if parent unregistration has started */ 299 if (!down_read_trylock(&parent->unreg_sem)) { 300 ret = -ENODEV; 301 goto out_put_device; 302 } 303 304 if (parent->ops->create) { 305 ret = parent->ops->create(mdev); 306 if (ret) 307 goto out_unlock; 308 } 309 310 ret = device_add(&mdev->dev); 311 if (ret) 312 goto out_remove; 313 314 if (!drv) 315 drv = &vfio_mdev_driver; 316 ret = device_driver_attach(&drv->driver, &mdev->dev); 317 if (ret) 318 goto out_del; 319 320 ret = mdev_create_sysfs_files(mdev); 321 if (ret) 322 goto out_del; 323 324 mdev->active = true; 325 dev_dbg(&mdev->dev, "MDEV: created\n"); 326 up_read(&parent->unreg_sem); 327 328 return 0; 329 330 out_del: 331 device_del(&mdev->dev); 332 out_remove: 333 if (parent->ops->remove) 334 parent->ops->remove(mdev); 335 out_unlock: 336 up_read(&parent->unreg_sem); 337 out_put_device: 338 put_device(&mdev->dev); 339 return ret; 340 } 341 342 int mdev_device_remove(struct mdev_device *mdev) 343 { 344 struct mdev_device *tmp; 345 struct mdev_parent *parent = mdev->type->parent; 346 347 mutex_lock(&mdev_list_lock); 348 list_for_each_entry(tmp, &mdev_list, next) { 349 if (tmp == mdev) 350 break; 351 } 352 353 if (tmp != mdev) { 354 mutex_unlock(&mdev_list_lock); 355 return -ENODEV; 356 } 357 358 if (!mdev->active) { 359 mutex_unlock(&mdev_list_lock); 360 return -EAGAIN; 361 } 362 363 mdev->active = false; 364 mutex_unlock(&mdev_list_lock); 365 366 /* Check if parent unregistration has started */ 367 if (!down_read_trylock(&parent->unreg_sem)) 368 return -ENODEV; 369 370 mdev_device_remove_common(mdev); 371 up_read(&parent->unreg_sem); 372 return 0; 373 } 374 375 static int __init mdev_init(void) 376 { 377 int rc; 378 379 rc = mdev_bus_register(); 380 if (rc) 381 return rc; 382 rc = mdev_register_driver(&vfio_mdev_driver); 383 if (rc) 384 goto err_bus; 385 return 0; 386 err_bus: 387 mdev_bus_unregister(); 388 return rc; 389 } 390 391 static void __exit mdev_exit(void) 392 { 393 mdev_unregister_driver(&vfio_mdev_driver); 394 395 if (mdev_bus_compat_class) 396 class_compat_unregister(mdev_bus_compat_class); 397 398 mdev_bus_unregister(); 399 } 400 401 module_init(mdev_init) 402 module_exit(mdev_exit) 403 404 MODULE_VERSION(DRIVER_VERSION); 405 MODULE_LICENSE("GPL v2"); 406 MODULE_AUTHOR(DRIVER_AUTHOR); 407 MODULE_DESCRIPTION(DRIVER_DESC); 408