drivers/vfio/mdev/mdev_core.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Mediated device Core Driver
  *
  * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
  *     Author: Neo Jia <cjia@nvidia.com>
  *             Kirti Wankhede <kwankhede@nvidia.com>
  */

 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/uuid.h>
 #include <linux/sysfs.h>
 #include <linux/mdev.h>

 #include "mdev_private.h"

 #define DRIVER_VERSION		"0.1"
 #define DRIVER_AUTHOR		"NVIDIA Corporation"
 #define DRIVER_DESC		"Mediated device Core Driver"

 static LIST_HEAD(parent_list);
 static DEFINE_MUTEX(parent_list_lock);
 static struct class_compat *mdev_bus_compat_class;

 static LIST_HEAD(mdev_list);
 static DEFINE_MUTEX(mdev_list_lock);

 struct device *mdev_parent_dev(struct mdev_device *mdev)
 {
 	return mdev->type->parent->dev;
 }
 EXPORT_SYMBOL(mdev_parent_dev);

 /*
  * Return the index in supported_type_groups that this mdev_device was created
  * from.
  */
 unsigned int mdev_get_type_group_id(struct mdev_device *mdev)
 {
 	return mdev->type->type_group_id;
 }
 EXPORT_SYMBOL(mdev_get_type_group_id);

 /*
  * Used in mdev_type_attribute sysfs functions to return the index in the
  * supported_type_groups that the sysfs is called from.
  */
 unsigned int mtype_get_type_group_id(struct mdev_type *mtype)
 {
 	return mtype->type_group_id;
 }
 EXPORT_SYMBOL(mtype_get_type_group_id);

 /*
  * Used in mdev_type_attribute sysfs functions to return the parent struct
  * device
  */
 struct device *mtype_get_parent_dev(struct mdev_type *mtype)
 {
 	return mtype->parent->dev;
 }
 EXPORT_SYMBOL(mtype_get_parent_dev);

 /* Should be called holding parent_list_lock */
 static struct mdev_parent *__find_parent_device(struct device *dev)
 {
 	struct mdev_parent *parent;

 	list_for_each_entry(parent, &parent_list, next) {
 		if (parent->dev == dev)
 			return parent;
 	}
 	return NULL;
 }

 void mdev_release_parent(struct kref *kref)
 {
 	struct mdev_parent *parent = container_of(kref, struct mdev_parent,
 						  ref);
 	struct device *dev = parent->dev;

 	kfree(parent);
 	put_device(dev);
 }

 /* Caller must hold parent unreg_sem read or write lock */
 static void mdev_device_remove_common(struct mdev_device *mdev)
 {
 	struct mdev_parent *parent = mdev->type->parent;
 	int ret;

 	mdev_remove_sysfs_files(mdev);
 	device_del(&mdev->dev);
 	lockdep_assert_held(&parent->unreg_sem);
 	if (parent->ops->remove) {
 		ret = parent->ops->remove(mdev);
 		if (ret)
 			dev_err(&mdev->dev, "Remove failed: err=%d\n", ret);
 	}

 	/* Balances with device_initialize() */
 	put_device(&mdev->dev);
 }

 static int mdev_device_remove_cb(struct device *dev, void *data)
 {
 	struct mdev_device *mdev = mdev_from_dev(dev);

 	if (mdev)
 		mdev_device_remove_common(mdev);
 	return 0;
 }

 /*
  * mdev_register_device : Register a device
  * @dev: device structure representing parent device.
  * @ops: Parent device operation structure to be registered.
  *
  * Add device to list of registered parent devices.
  * Returns a negative value on error, otherwise 0.
  */
 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
 {
 	int ret;
 	struct mdev_parent *parent;
 	char *env_string = "MDEV_STATE=registered";
 	char *envp[] = { env_string, NULL };

 	/* check for mandatory ops */
 	if (!ops || !ops->supported_type_groups)
 		return -EINVAL;
 	if (!ops->device_driver && (!ops->create || !ops->remove))
 		return -EINVAL;

 	dev = get_device(dev);
 	if (!dev)
 		return -EINVAL;

 	mutex_lock(&parent_list_lock);

 	/* Check for duplicate */
 	parent = __find_parent_device(dev);
 	if (parent) {
 		parent = NULL;
 		ret = -EEXIST;
 		goto add_dev_err;
 	}

 	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
 	if (!parent) {
 		ret = -ENOMEM;
 		goto add_dev_err;
 	}

 	kref_init(&parent->ref);
 	init_rwsem(&parent->unreg_sem);

 	parent->dev = dev;
 	parent->ops = ops;

 	if (!mdev_bus_compat_class) {
 		mdev_bus_compat_class = class_compat_register("mdev_bus");
 		if (!mdev_bus_compat_class) {
 			ret = -ENOMEM;
 			goto add_dev_err;
 		}
 	}

 	ret = parent_create_sysfs_files(parent);
 	if (ret)
 		goto add_dev_err;

 	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
 	if (ret)
 		dev_warn(dev, "Failed to create compatibility class link\n");

 	list_add(&parent->next, &parent_list);
 	mutex_unlock(&parent_list_lock);

 	dev_info(dev, "MDEV: Registered\n");
 	kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);

 	return 0;

 add_dev_err:
 	mutex_unlock(&parent_list_lock);
 	if (parent)
 		mdev_put_parent(parent);
 	else
 		put_device(dev);
 	return ret;
 }
 EXPORT_SYMBOL(mdev_register_device);

 /*
  * mdev_unregister_device : Unregister a parent device
  * @dev: device structure representing parent device.
  *
  * Remove device from list of registered parent devices. Give a chance to free
  * existing mediated devices for given device.
  */

 void mdev_unregister_device(struct device *dev)
 {
 	struct mdev_parent *parent;
 	char *env_string = "MDEV_STATE=unregistered";
 	char *envp[] = { env_string, NULL };

 	mutex_lock(&parent_list_lock);
 	parent = __find_parent_device(dev);

 	if (!parent) {
 		mutex_unlock(&parent_list_lock);
 		return;
 	}
 	dev_info(dev, "MDEV: Unregistering\n");

 	list_del(&parent->next);
 	mutex_unlock(&parent_list_lock);

 	down_write(&parent->unreg_sem);

 	class_compat_remove_link(mdev_bus_compat_class, dev, NULL);

 	device_for_each_child(dev, NULL, mdev_device_remove_cb);

 	parent_remove_sysfs_files(parent);
 	up_write(&parent->unreg_sem);

 	mdev_put_parent(parent);

 	/* We still have the caller's reference to use for the uevent */
 	kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
 }
 EXPORT_SYMBOL(mdev_unregister_device);

 static void mdev_device_release(struct device *dev)
 {
 	struct mdev_device *mdev = to_mdev_device(dev);

 	/* Pairs with the get in mdev_device_create() */
 	kobject_put(&mdev->type->kobj);

 	mutex_lock(&mdev_list_lock);
 	list_del(&mdev->next);
 	mutex_unlock(&mdev_list_lock);

 	dev_dbg(&mdev->dev, "MDEV: destroying\n");
 	kfree(mdev);
 }

 int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
 {
 	int ret;
 	struct mdev_device *mdev, *tmp;
 	struct mdev_parent *parent = type->parent;
 	struct mdev_driver *drv = parent->ops->device_driver;

 	mutex_lock(&mdev_list_lock);

 	/* Check for duplicate */
 	list_for_each_entry(tmp, &mdev_list, next) {
 		if (guid_equal(&tmp->uuid, uuid)) {
 			mutex_unlock(&mdev_list_lock);
 			return -EEXIST;
 		}
 	}

 	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
 	if (!mdev) {
 		mutex_unlock(&mdev_list_lock);
 		return -ENOMEM;
 	}

 	device_initialize(&mdev->dev);
 	mdev->dev.parent  = parent->dev;
 	mdev->dev.bus = &mdev_bus_type;
 	mdev->dev.release = mdev_device_release;
 	mdev->dev.groups = parent->ops->mdev_attr_groups;
 	mdev->type = type;
 	/* Pairs with the put in mdev_device_release() */
 	kobject_get(&type->kobj);

 	guid_copy(&mdev->uuid, uuid);
 	list_add(&mdev->next, &mdev_list);
 	mutex_unlock(&mdev_list_lock);

 	ret = dev_set_name(&mdev->dev, "%pUl", uuid);
 	if (ret)
 		goto out_put_device;

 	/* Check if parent unregistration has started */
 	if (!down_read_trylock(&parent->unreg_sem)) {
 		ret = -ENODEV;
 		goto out_put_device;
 	}

 	if (parent->ops->create) {
 		ret = parent->ops->create(mdev);
 		if (ret)
 			goto out_unlock;
 	}

 	ret = device_add(&mdev->dev);
 	if (ret)
 		goto out_remove;

 	if (!drv)
 		drv = &vfio_mdev_driver;
 	ret = device_driver_attach(&drv->driver, &mdev->dev);
 	if (ret)
 		goto out_del;

 	ret = mdev_create_sysfs_files(mdev);
 	if (ret)
 		goto out_del;

 	mdev->active = true;
 	dev_dbg(&mdev->dev, "MDEV: created\n");
 	up_read(&parent->unreg_sem);

 	return 0;

 out_del:
 	device_del(&mdev->dev);
 out_remove:
 	if (parent->ops->remove)
 		parent->ops->remove(mdev);
 out_unlock:
 	up_read(&parent->unreg_sem);
 out_put_device:
 	put_device(&mdev->dev);
 	return ret;
 }

 int mdev_device_remove(struct mdev_device *mdev)
 {
 	struct mdev_device *tmp;
 	struct mdev_parent *parent = mdev->type->parent;

 	mutex_lock(&mdev_list_lock);
 	list_for_each_entry(tmp, &mdev_list, next) {
 		if (tmp == mdev)
 			break;
 	}

 	if (tmp != mdev) {
 		mutex_unlock(&mdev_list_lock);
 		return -ENODEV;
 	}

 	if (!mdev->active) {
 		mutex_unlock(&mdev_list_lock);
 		return -EAGAIN;
 	}

 	mdev->active = false;
 	mutex_unlock(&mdev_list_lock);

 	/* Check if parent unregistration has started */
 	if (!down_read_trylock(&parent->unreg_sem))
 		return -ENODEV;

 	mdev_device_remove_common(mdev);
 	up_read(&parent->unreg_sem);
 	return 0;
 }

 static int __init mdev_init(void)
 {
 	int rc;

 	rc = mdev_bus_register();
 	if (rc)
 		return rc;
 	rc = mdev_register_driver(&vfio_mdev_driver);
 	if (rc)
 		goto err_bus;
 	return 0;
 err_bus:
 	mdev_bus_unregister();
 	return rc;
 }

 static void __exit mdev_exit(void)
 {
 	mdev_unregister_driver(&vfio_mdev_driver);

 	if (mdev_bus_compat_class)
 		class_compat_unregister(mdev_bus_compat_class);

 	mdev_bus_unregister();
 }

 subsys_initcall(mdev_init)
 module_exit(mdev_exit)

 MODULE_VERSION(DRIVER_VERSION);
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR(DRIVER_AUTHOR);
 MODULE_DESCRIPTION(DRIVER_DESC);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Mediated device Core Driver
	*
	* Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
	* Author: Neo Jia <cjia@nvidia.com>
	* Kirti Wankhede <kwankhede@nvidia.com>
	*/

	#include <linux/module.h>
	#include <linux/device.h>
	#include <linux/slab.h>
	#include <linux/uuid.h>
	#include <linux/sysfs.h>
	#include <linux/mdev.h>

	#include "mdev_private.h"

	#define DRIVER_VERSION "0.1"
	#define DRIVER_AUTHOR "NVIDIA Corporation"
	#define DRIVER_DESC "Mediated device Core Driver"

	static LIST_HEAD(parent_list);
	static DEFINE_MUTEX(parent_list_lock);
	static struct class_compat *mdev_bus_compat_class;

	static LIST_HEAD(mdev_list);
	static DEFINE_MUTEX(mdev_list_lock);

	struct device mdev_parent_dev(struct mdev_device mdev)
	{
	return mdev->type->parent->dev;
	}
	EXPORT_SYMBOL(mdev_parent_dev);

	/*
	* Return the index in supported_type_groups that this mdev_device was created
	* from.
	*/
	unsigned int mdev_get_type_group_id(struct mdev_device *mdev)
	{
	return mdev->type->type_group_id;
	}
	EXPORT_SYMBOL(mdev_get_type_group_id);

	/*
	* Used in mdev_type_attribute sysfs functions to return the index in the
	* supported_type_groups that the sysfs is called from.
	*/
	unsigned int mtype_get_type_group_id(struct mdev_type *mtype)
	{
	return mtype->type_group_id;
	}
	EXPORT_SYMBOL(mtype_get_type_group_id);

	/*
	* Used in mdev_type_attribute sysfs functions to return the parent struct
	* device
	*/
	struct device mtype_get_parent_dev(struct mdev_type mtype)
	{
	return mtype->parent->dev;
	}
	EXPORT_SYMBOL(mtype_get_parent_dev);

	/* Should be called holding parent_list_lock */
	static struct mdev_parent __find_parent_device(struct device dev)
	{
	struct mdev_parent *parent;

	list_for_each_entry(parent, &parent_list, next) {
	if (parent->dev == dev)
	return parent;
	}
	return NULL;
	}

	void mdev_release_parent(struct kref *kref)
	{
	struct mdev_parent *parent = container_of(kref, struct mdev_parent,
	ref);
	struct device *dev = parent->dev;

	kfree(parent);
	put_device(dev);
	}

	/* Caller must hold parent unreg_sem read or write lock */
	static void mdev_device_remove_common(struct mdev_device *mdev)
	{
	struct mdev_parent *parent = mdev->type->parent;
	int ret;

	mdev_remove_sysfs_files(mdev);
	device_del(&mdev->dev);
	lockdep_assert_held(&parent->unreg_sem);
	if (parent->ops->remove) {
	ret = parent->ops->remove(mdev);
	if (ret)
	dev_err(&mdev->dev, "Remove failed: err=%d\n", ret);
	}

	/* Balances with device_initialize() */
	put_device(&mdev->dev);
	}

	static int mdev_device_remove_cb(struct device dev, void data)
	{
	struct mdev_device *mdev = mdev_from_dev(dev);

	if (mdev)
	mdev_device_remove_common(mdev);
	return 0;
	}

	/*
	* mdev_register_device : Register a device
	* @dev: device structure representing parent device.
	* @ops: Parent device operation structure to be registered.
	*
	* Add device to list of registered parent devices.
	* Returns a negative value on error, otherwise 0.
	*/
	int mdev_register_device(struct device dev, const struct mdev_parent_ops ops)
	{
	int ret;
	struct mdev_parent *parent;
	char *env_string = "MDEV_STATE=registered";
	char *envp[] = { env_string, NULL };

	/* check for mandatory ops */
	if (!ops \|\| !ops->supported_type_groups)
	return -EINVAL;
	if (!ops->device_driver && (!ops->create \|\| !ops->remove))
	return -EINVAL;

	dev = get_device(dev);
	if (!dev)
	return -EINVAL;

	mutex_lock(&parent_list_lock);

	/* Check for duplicate */
	parent = __find_parent_device(dev);
	if (parent) {
	parent = NULL;
	ret = -EEXIST;
	goto add_dev_err;
	}

	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
	if (!parent) {
	ret = -ENOMEM;
	goto add_dev_err;
	}

	kref_init(&parent->ref);
	init_rwsem(&parent->unreg_sem);

	parent->dev = dev;
	parent->ops = ops;

	if (!mdev_bus_compat_class) {
	mdev_bus_compat_class = class_compat_register("mdev_bus");
	if (!mdev_bus_compat_class) {
	ret = -ENOMEM;
	goto add_dev_err;
	}
	}

	ret = parent_create_sysfs_files(parent);
	if (ret)
	goto add_dev_err;

	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
	if (ret)
	dev_warn(dev, "Failed to create compatibility class link\n");

	list_add(&parent->next, &parent_list);
	mutex_unlock(&parent_list_lock);

	dev_info(dev, "MDEV: Registered\n");
	kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);

	return 0;

	add_dev_err:
	mutex_unlock(&parent_list_lock);
	if (parent)
	mdev_put_parent(parent);
	else
	put_device(dev);
	return ret;
	}
	EXPORT_SYMBOL(mdev_register_device);

	/*
	* mdev_unregister_device : Unregister a parent device
	* @dev: device structure representing parent device.
	*
	* Remove device from list of registered parent devices. Give a chance to free
	* existing mediated devices for given device.
	*/

	void mdev_unregister_device(struct device *dev)
	{
	struct mdev_parent *parent;
	char *env_string = "MDEV_STATE=unregistered";
	char *envp[] = { env_string, NULL };

	mutex_lock(&parent_list_lock);
	parent = __find_parent_device(dev);

	if (!parent) {
	mutex_unlock(&parent_list_lock);
	return;
	}
	dev_info(dev, "MDEV: Unregistering\n");

	list_del(&parent->next);
	mutex_unlock(&parent_list_lock);

	down_write(&parent->unreg_sem);

	class_compat_remove_link(mdev_bus_compat_class, dev, NULL);

	device_for_each_child(dev, NULL, mdev_device_remove_cb);

	parent_remove_sysfs_files(parent);
	up_write(&parent->unreg_sem);

	mdev_put_parent(parent);

	/* We still have the caller's reference to use for the uevent */
	kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
	}
	EXPORT_SYMBOL(mdev_unregister_device);

	static void mdev_device_release(struct device *dev)
	{
	struct mdev_device *mdev = to_mdev_device(dev);

	/* Pairs with the get in mdev_device_create() */
	kobject_put(&mdev->type->kobj);

	mutex_lock(&mdev_list_lock);
	list_del(&mdev->next);
	mutex_unlock(&mdev_list_lock);

	dev_dbg(&mdev->dev, "MDEV: destroying\n");
	kfree(mdev);
	}

	int mdev_device_create(struct mdev_type type, const guid_t uuid)
	{
	int ret;
	struct mdev_device mdev, tmp;
	struct mdev_parent *parent = type->parent;
	struct mdev_driver *drv = parent->ops->device_driver;

	mutex_lock(&mdev_list_lock);

	/* Check for duplicate */
	list_for_each_entry(tmp, &mdev_list, next) {
	if (guid_equal(&tmp->uuid, uuid)) {
	mutex_unlock(&mdev_list_lock);
	return -EEXIST;
	}
	}

	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
	if (!mdev) {
	mutex_unlock(&mdev_list_lock);
	return -ENOMEM;
	}

	device_initialize(&mdev->dev);
	mdev->dev.parent = parent->dev;
	mdev->dev.bus = &mdev_bus_type;
	mdev->dev.release = mdev_device_release;
	mdev->dev.groups = parent->ops->mdev_attr_groups;
	mdev->type = type;
	/* Pairs with the put in mdev_device_release() */
	kobject_get(&type->kobj);

	guid_copy(&mdev->uuid, uuid);
	list_add(&mdev->next, &mdev_list);
	mutex_unlock(&mdev_list_lock);

	ret = dev_set_name(&mdev->dev, "%pUl", uuid);
	if (ret)
	goto out_put_device;

	/* Check if parent unregistration has started */
	if (!down_read_trylock(&parent->unreg_sem)) {
	ret = -ENODEV;
	goto out_put_device;
	}

	if (parent->ops->create) {
	ret = parent->ops->create(mdev);
	if (ret)
	goto out_unlock;
	}

	ret = device_add(&mdev->dev);
	if (ret)
	goto out_remove;

	if (!drv)
	drv = &vfio_mdev_driver;
	ret = device_driver_attach(&drv->driver, &mdev->dev);
	if (ret)
	goto out_del;

	ret = mdev_create_sysfs_files(mdev);
	if (ret)
	goto out_del;

	mdev->active = true;
	dev_dbg(&mdev->dev, "MDEV: created\n");
	up_read(&parent->unreg_sem);

	return 0;

	out_del:
	device_del(&mdev->dev);
	out_remove:
	if (parent->ops->remove)
	parent->ops->remove(mdev);
	out_unlock:
	up_read(&parent->unreg_sem);
	out_put_device:
	put_device(&mdev->dev);
	return ret;
	}

	int mdev_device_remove(struct mdev_device *mdev)
	{
	struct mdev_device *tmp;
	struct mdev_parent *parent = mdev->type->parent;

	mutex_lock(&mdev_list_lock);
	list_for_each_entry(tmp, &mdev_list, next) {
	if (tmp == mdev)
	break;
	}

	if (tmp != mdev) {
	mutex_unlock(&mdev_list_lock);
	return -ENODEV;
	}

	if (!mdev->active) {
	mutex_unlock(&mdev_list_lock);
	return -EAGAIN;
	}

	mdev->active = false;
	mutex_unlock(&mdev_list_lock);

	/* Check if parent unregistration has started */
	if (!down_read_trylock(&parent->unreg_sem))
	return -ENODEV;

	mdev_device_remove_common(mdev);
	up_read(&parent->unreg_sem);
	return 0;
	}

	static int __init mdev_init(void)
	{
	int rc;

	rc = mdev_bus_register();
	if (rc)
	return rc;
	rc = mdev_register_driver(&vfio_mdev_driver);
	if (rc)
	goto err_bus;
	return 0;
	err_bus:
	mdev_bus_unregister();
	return rc;
	}

	static void __exit mdev_exit(void)
	{
	mdev_unregister_driver(&vfio_mdev_driver);

	if (mdev_bus_compat_class)
	class_compat_unregister(mdev_bus_compat_class);

	mdev_bus_unregister();
	}

	subsys_initcall(mdev_init)
	module_exit(mdev_exit)

	MODULE_VERSION(DRIVER_VERSION);
	MODULE_LICENSE("GPL v2");
	MODULE_AUTHOR(DRIVER_AUTHOR);
	MODULE_DESCRIPTION(DRIVER_DESC);