drivers/vfio/mdev/mdev_core.c

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