RE: [PATCH v9 02/12] vfio: VFIO based driver for Mediated devices

["Tian, Kevin" <kevin.tian@intel.com>]

> From: Kirti Wankhede [mailto:kwankhede@nvidia.com]
> Sent: Tuesday, October 18, 2016 5:22 AM
> 
> vfio_mdev driver registers with mdev core driver.
> MDEV core driver creates mediated device and calls probe routine of

use same case - either 'mdev core' or 'MDEV core'

> vfio_mdev driver for each device.
> Probe routine of vfio_mdev driver adds mediated device to VFIO core module
> 
> This driver forms a shim layer that pass through VFIO devices operations
> to vendor driver for mediated devices.
> 
> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
> Signed-off-by: Neo Jia <cjia@nvidia.com>
> Change-Id: I583f4734752971d3d112324d69e2508c88f359ec
> ---
>  drivers/vfio/mdev/Kconfig     |   7 ++
>  drivers/vfio/mdev/Makefile    |   1 +
>  drivers/vfio/mdev/vfio_mdev.c | 148
> ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 156 insertions(+)
>  create mode 100644 drivers/vfio/mdev/vfio_mdev.c
> 
> diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig
> index 93addace9a67..6cef0c4d2ceb 100644
> --- a/drivers/vfio/mdev/Kconfig
> +++ b/drivers/vfio/mdev/Kconfig
> @@ -9,3 +9,10 @@ config VFIO_MDEV
>  	See Documentation/vfio-mdev/vfio-mediated-device.txt for more details.
> 
>          If you don't know what do here, say N.
> +
> +config VFIO_MDEV_DEVICE
> +    tristate "VFIO support for Mediated devices"
> +    depends on VFIO && VFIO_MDEV
> +    default n
> +    help
> +        VFIO based driver for mediated devices.
> diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile
> index 31bc04801d94..fa2d5ea466ee 100644
> --- a/drivers/vfio/mdev/Makefile
> +++ b/drivers/vfio/mdev/Makefile
> @@ -2,3 +2,4 @@
>  mdev-y := mdev_core.o mdev_sysfs.o mdev_driver.o
> 
>  obj-$(CONFIG_VFIO_MDEV) += mdev.o
> +obj-$(CONFIG_VFIO_MDEV_DEVICE) += vfio_mdev.o
> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> new file mode 100644
> index 000000000000..b7b47604ce7a
> --- /dev/null
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -0,0 +1,148 @@
> +/*
> + * VFIO based driver for Mediated device
> + *
> + * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
> + *     Author: Neo Jia <cjia@nvidia.com>
> + *	       Kirti Wankhede <kwankhede@nvidia.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/vfio.h>
> +#include <linux/mdev.h>
> +
> +#include "mdev_private.h"
> +
> +#define DRIVER_VERSION  "0.1"
> +#define DRIVER_AUTHOR   "NVIDIA Corporation"
> +#define DRIVER_DESC     "VFIO based driver for Mediated device"
> +
> +static int vfio_mdev_open(void *device_data)
> +{
> +	struct mdev_device *mdev = device_data;
> +	struct parent_device *parent = mdev->parent;
> +	int ret;
> +
> +	if (unlikely(!parent->ops->open))
> +		return -EINVAL;
> +
> +	if (!try_module_get(THIS_MODULE))
> +		return -ENODEV;
> +
> +	ret = parent->ops->open(mdev);
> +	if (ret)
> +		module_put(THIS_MODULE);
> +
> +	return ret;
> +}
> +
> +static void vfio_mdev_release(void *device_data)
> +{
> +	struct mdev_device *mdev = device_data;
> +	struct parent_device *parent = mdev->parent;
> +
> +	if (parent->ops->release)

likely()

> +		parent->ops->release(mdev);
> +
> +	module_put(THIS_MODULE);
> +}
> +
> +static long vfio_mdev_unlocked_ioctl(void *device_data,
> +				     unsigned int cmd, unsigned long arg)
> +{
> +	struct mdev_device *mdev = device_data;
> +	struct parent_device *parent = mdev->parent;
> +
> +	if (unlikely(!parent->ops->ioctl))
> +		return -EINVAL;
> +
> +	return parent->ops->ioctl(mdev, cmd, arg);
> +}
> +
> +static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
> +			      size_t count, loff_t *ppos)
> +{
> +	struct mdev_device *mdev = device_data;
> +	struct parent_device *parent = mdev->parent;
> +
> +	if (unlikely(!parent->ops->read))
> +		return -EINVAL;
> +
> +	return parent->ops->read(mdev, buf, count, ppos);
> +}
> +
> +static ssize_t vfio_mdev_write(void *device_data, const char __user *buf,
> +			       size_t count, loff_t *ppos)
> +{
> +	struct mdev_device *mdev = device_data;
> +	struct parent_device *parent = mdev->parent;
> +
> +	if (unlikely(!parent->ops->write))
> +		return -EINVAL;
> +
> +	return parent->ops->write(mdev, buf, count, ppos);
> +}
> +
> +static int vfio_mdev_mmap(void *device_data, struct vm_area_struct *vma)
> +{
> +	struct mdev_device *mdev = device_data;
> +	struct parent_device *parent = mdev->parent;
> +
> +	if (unlikely(!parent->ops->mmap))
> +		return -EINVAL;
> +
> +	return parent->ops->mmap(mdev, vma);
> +}
> +
> +static const struct vfio_device_ops vfio_mdev_dev_ops = {
> +	.name		= "vfio-mdev",
> +	.open		= vfio_mdev_open,
> +	.release	= vfio_mdev_release,
> +	.ioctl		= vfio_mdev_unlocked_ioctl,
> +	.read		= vfio_mdev_read,
> +	.write		= vfio_mdev_write,
> +	.mmap		= vfio_mdev_mmap,
> +};
> +
> +int vfio_mdev_probe(struct device *dev)
> +{
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +
> +	return vfio_add_group_dev(dev, &vfio_mdev_dev_ops, mdev);
> +}
> +
> +void vfio_mdev_remove(struct device *dev)
> +{
> +	vfio_del_group_dev(dev);
> +}
> +
> +struct mdev_driver vfio_mdev_driver = {
> +	.name	= "vfio_mdev",
> +	.probe	= vfio_mdev_probe,
> +	.remove	= vfio_mdev_remove,
> +};
> +
> +static int __init vfio_mdev_init(void)
> +{
> +	return mdev_register_driver(&vfio_mdev_driver, THIS_MODULE);
> +}
> +
> +static void __exit vfio_mdev_exit(void)
> +{
> +	mdev_unregister_driver(&vfio_mdev_driver);
> +}
> +
> +module_init(vfio_mdev_init)
> +module_exit(vfio_mdev_exit)
> +
> +MODULE_VERSION(DRIVER_VERSION);
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR(DRIVER_AUTHOR);
> +MODULE_DESCRIPTION(DRIVER_DESC);
> --
> 2.7.0