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