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 <[email protected]> 7 * Kirti Wankhede <[email protected]> 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 kobject *mtype_kobj) 51 { 52 return container_of(mtype_kobj, struct mdev_type, kobj)->type_group_id; 53 } 54 EXPORT_SYMBOL(mtype_get_type_group_id); 55 56 /* Should be called holding parent_list_lock */ 57 static struct mdev_parent *__find_parent_device(struct device *dev) 58 { 59 struct mdev_parent *parent; 60 61 list_for_each_entry(parent, &parent_list, next) { 62 if (parent->dev == dev) 63 return parent; 64 } 65 return NULL; 66 } 67 68 void mdev_release_parent(struct kref *kref) 69 { 70 struct mdev_parent *parent = container_of(kref, struct mdev_parent, 71 ref); 72 struct device *dev = parent->dev; 73 74 kfree(parent); 75 put_device(dev); 76 } 77 78 /* Caller must hold parent unreg_sem read or write lock */ 79 static void mdev_device_remove_common(struct mdev_device *mdev) 80 { 81 struct mdev_parent *parent = mdev->type->parent; 82 int ret; 83 84 mdev_remove_sysfs_files(mdev); 85 device_del(&mdev->dev); 86 lockdep_assert_held(&parent->unreg_sem); 87 ret = parent->ops->remove(mdev); 88 if (ret) 89 dev_err(&mdev->dev, "Remove failed: err=%d\n", ret); 90 91 /* Balances with device_initialize() */ 92 put_device(&mdev->dev); 93 } 94 95 static int mdev_device_remove_cb(struct device *dev, void *data) 96 { 97 struct mdev_device *mdev = mdev_from_dev(dev); 98 99 if (mdev) 100 mdev_device_remove_common(mdev); 101 return 0; 102 } 103 104 /* 105 * mdev_register_device : Register a device 106 * @dev: device structure representing parent device. 107 * @ops: Parent device operation structure to be registered. 108 * 109 * Add device to list of registered parent devices. 110 * Returns a negative value on error, otherwise 0. 111 */ 112 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops) 113 { 114 int ret; 115 struct mdev_parent *parent; 116 char *env_string = "MDEV_STATE=registered"; 117 char *envp[] = { env_string, NULL }; 118 119 /* check for mandatory ops */ 120 if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups) 121 return -EINVAL; 122 123 dev = get_device(dev); 124 if (!dev) 125 return -EINVAL; 126 127 /* Not mandatory, but its absence could be a problem */ 128 if (!ops->request) 129 dev_info(dev, "Driver cannot be asked to release device\n"); 130 131 mutex_lock(&parent_list_lock); 132 133 /* Check for duplicate */ 134 parent = __find_parent_device(dev); 135 if (parent) { 136 parent = NULL; 137 ret = -EEXIST; 138 goto add_dev_err; 139 } 140 141 parent = kzalloc(sizeof(*parent), GFP_KERNEL); 142 if (!parent) { 143 ret = -ENOMEM; 144 goto add_dev_err; 145 } 146 147 kref_init(&parent->ref); 148 init_rwsem(&parent->unreg_sem); 149 150 parent->dev = dev; 151 parent->ops = ops; 152 153 if (!mdev_bus_compat_class) { 154 mdev_bus_compat_class = class_compat_register("mdev_bus"); 155 if (!mdev_bus_compat_class) { 156 ret = -ENOMEM; 157 goto add_dev_err; 158 } 159 } 160 161 ret = parent_create_sysfs_files(parent); 162 if (ret) 163 goto add_dev_err; 164 165 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL); 166 if (ret) 167 dev_warn(dev, "Failed to create compatibility class link\n"); 168 169 list_add(&parent->next, &parent_list); 170 mutex_unlock(&parent_list_lock); 171 172 dev_info(dev, "MDEV: Registered\n"); 173 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); 174 175 return 0; 176 177 add_dev_err: 178 mutex_unlock(&parent_list_lock); 179 if (parent) 180 mdev_put_parent(parent); 181 else 182 put_device(dev); 183 return ret; 184 } 185 EXPORT_SYMBOL(mdev_register_device); 186 187 /* 188 * mdev_unregister_device : Unregister a parent device 189 * @dev: device structure representing parent device. 190 * 191 * Remove device from list of registered parent devices. Give a chance to free 192 * existing mediated devices for given device. 193 */ 194 195 void mdev_unregister_device(struct device *dev) 196 { 197 struct mdev_parent *parent; 198 char *env_string = "MDEV_STATE=unregistered"; 199 char *envp[] = { env_string, NULL }; 200 201 mutex_lock(&parent_list_lock); 202 parent = __find_parent_device(dev); 203 204 if (!parent) { 205 mutex_unlock(&parent_list_lock); 206 return; 207 } 208 dev_info(dev, "MDEV: Unregistering\n"); 209 210 list_del(&parent->next); 211 mutex_unlock(&parent_list_lock); 212 213 down_write(&parent->unreg_sem); 214 215 class_compat_remove_link(mdev_bus_compat_class, dev, NULL); 216 217 device_for_each_child(dev, NULL, mdev_device_remove_cb); 218 219 parent_remove_sysfs_files(parent); 220 up_write(&parent->unreg_sem); 221 222 mdev_put_parent(parent); 223 224 /* We still have the caller's reference to use for the uevent */ 225 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp); 226 } 227 EXPORT_SYMBOL(mdev_unregister_device); 228 229 static void mdev_device_release(struct device *dev) 230 { 231 struct mdev_device *mdev = to_mdev_device(dev); 232 233 /* Pairs with the get in mdev_device_create() */ 234 kobject_put(&mdev->type->kobj); 235 236 mutex_lock(&mdev_list_lock); 237 list_del(&mdev->next); 238 mutex_unlock(&mdev_list_lock); 239 240 dev_dbg(&mdev->dev, "MDEV: destroying\n"); 241 kfree(mdev); 242 } 243 244 int mdev_device_create(struct mdev_type *type, const guid_t *uuid) 245 { 246 int ret; 247 struct mdev_device *mdev, *tmp; 248 struct mdev_parent *parent = type->parent; 249 250 mutex_lock(&mdev_list_lock); 251 252 /* Check for duplicate */ 253 list_for_each_entry(tmp, &mdev_list, next) { 254 if (guid_equal(&tmp->uuid, uuid)) { 255 mutex_unlock(&mdev_list_lock); 256 return -EEXIST; 257 } 258 } 259 260 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); 261 if (!mdev) { 262 mutex_unlock(&mdev_list_lock); 263 return -ENOMEM; 264 } 265 266 device_initialize(&mdev->dev); 267 mdev->dev.parent = parent->dev; 268 mdev->dev.bus = &mdev_bus_type; 269 mdev->dev.release = mdev_device_release; 270 mdev->dev.groups = parent->ops->mdev_attr_groups; 271 mdev->type = type; 272 /* Pairs with the put in mdev_device_release() */ 273 kobject_get(&type->kobj); 274 275 guid_copy(&mdev->uuid, uuid); 276 list_add(&mdev->next, &mdev_list); 277 mutex_unlock(&mdev_list_lock); 278 279 ret = dev_set_name(&mdev->dev, "%pUl", uuid); 280 if (ret) 281 goto out_put_device; 282 283 /* Check if parent unregistration has started */ 284 if (!down_read_trylock(&parent->unreg_sem)) { 285 ret = -ENODEV; 286 goto out_put_device; 287 } 288 289 ret = parent->ops->create(mdev); 290 if (ret) 291 goto out_unlock; 292 293 ret = device_add(&mdev->dev); 294 if (ret) 295 goto out_remove; 296 297 ret = mdev_create_sysfs_files(mdev); 298 if (ret) 299 goto out_del; 300 301 mdev->active = true; 302 dev_dbg(&mdev->dev, "MDEV: created\n"); 303 up_read(&parent->unreg_sem); 304 305 return 0; 306 307 out_del: 308 device_del(&mdev->dev); 309 out_remove: 310 parent->ops->remove(mdev); 311 out_unlock: 312 up_read(&parent->unreg_sem); 313 out_put_device: 314 put_device(&mdev->dev); 315 return ret; 316 } 317 318 int mdev_device_remove(struct mdev_device *mdev) 319 { 320 struct mdev_device *tmp; 321 struct mdev_parent *parent = mdev->type->parent; 322 323 mutex_lock(&mdev_list_lock); 324 list_for_each_entry(tmp, &mdev_list, next) { 325 if (tmp == mdev) 326 break; 327 } 328 329 if (tmp != mdev) { 330 mutex_unlock(&mdev_list_lock); 331 return -ENODEV; 332 } 333 334 if (!mdev->active) { 335 mutex_unlock(&mdev_list_lock); 336 return -EAGAIN; 337 } 338 339 mdev->active = false; 340 mutex_unlock(&mdev_list_lock); 341 342 /* Check if parent unregistration has started */ 343 if (!down_read_trylock(&parent->unreg_sem)) 344 return -ENODEV; 345 346 mdev_device_remove_common(mdev); 347 up_read(&parent->unreg_sem); 348 return 0; 349 } 350 351 static int __init mdev_init(void) 352 { 353 return mdev_bus_register(); 354 } 355 356 static void __exit mdev_exit(void) 357 { 358 if (mdev_bus_compat_class) 359 class_compat_unregister(mdev_bus_compat_class); 360 361 mdev_bus_unregister(); 362 } 363 364 module_init(mdev_init) 365 module_exit(mdev_exit) 366 367 MODULE_VERSION(DRIVER_VERSION); 368 MODULE_LICENSE("GPL v2"); 369 MODULE_AUTHOR(DRIVER_AUTHOR); 370 MODULE_DESCRIPTION(DRIVER_DESC); 371 MODULE_SOFTDEP("post: vfio_mdev"); 372