Re: [PATCH 2/7] Initial skeleton of VFIO support for Device Tree based devices

[Don Dutile <ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 09/30/2013 11:37 AM, Bhushan Bharat-R65777 wrote:
>
>
>> -----Original Message-----
>> From: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org [mailto:iommu-
>> bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org] On Behalf Of Antonios Motakis
>> Sent: Monday, September 30, 2013 8:59 PM
>> To: kvmarm-FPEHb7Xf0XXUo1n7N8X6UoWGPAHP3yOg@public.gmane.org; alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
>> Cc: linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; agraf-l3A5Bk7waGM@public.gmane.org; Yoder
>> Stuart-B08248; iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org; Antonios Motakis;
>> tech-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org
>> Subject: [PATCH 2/7] Initial skeleton of VFIO support for Device Tree based
>> devices
>>
>> Platform devices in the Linux kernel are usually managed by the DT interface.
>> This patch forms the base to support these kind of devices with VFIO.
>>
>> Signed-off-by: Antonios Motakis<a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>
>> ---
>>   drivers/vfio/Kconfig         |  11 +++
>>   drivers/vfio/Makefile        |   1 +
>>   drivers/vfio/vfio_platform.c | 187 +++++++++++++++++++++++++++++++++++++++++++
>>   include/uapi/linux/vfio.h    |   1 +
>>   4 files changed, 200 insertions(+)
>>   create mode 100644 drivers/vfio/vfio_platform.c
>>
>> diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig index 1f84eda..35254b7
>> 100644
>> --- a/drivers/vfio/Kconfig
>> +++ b/drivers/vfio/Kconfig
>> @@ -13,4 +13,15 @@ menuconfig VFIO
>>
>>   	  If you don't know what to do here, say N.
>>
>> +config VFIO_PLATFORM
>> +	tristate "VFIO support for device tree based platform devices"
>> +	depends on VFIO&&  EVENTFD&&  OF
>> +	help
>> +	  Support for platform devices with VFIO. This is required to make
>> +	  use of platform devices present on device tree nodes using the VFIO
>> +	  framework. Devices that are not described in the device tree cannot
>> +	  be used by this driver.
>> +
>> +	  If you don't know what to do here, say N.
>> +
>>   source "drivers/vfio/pci/Kconfig"
>> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile index
>> 2398d4a..575c8dd 100644
>> --- a/drivers/vfio/Makefile
>> +++ b/drivers/vfio/Makefile
>> @@ -1,3 +1,4 @@
>>   obj-$(CONFIG_VFIO) += vfio.o
>>   obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
>>   obj-$(CONFIG_VFIO_PCI) += pci/
>> +obj-$(CONFIG_VFIO_PLATFORM) += vfio_platform.o
>> diff --git a/drivers/vfio/vfio_platform.c b/drivers/vfio/vfio_platform.c new
>
> We can make this parallel to PCI, something like drivers/vfio/platform/platform.c
>
pls, no.  'platform' is too generic, and it really means 'arm-dt' ... so can
move it to the arch/arm space, and have it's kconfig conditional on ARM&&VFIO.
if kept under drivers/vfio, then use a better directory name that ties it to arm-dt.
thanks.
- Don


> -Bharat
>
>> file mode 100644 index 0000000..b9686b0
>> --- /dev/null
>> +++ b/drivers/vfio/vfio_platform.c
>> @@ -0,0 +1,187 @@
>> +/*
>> + * Copyright (C) 2013 - Virtual Open Systems
>> + * Author: Antonios Motakis<a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>
>> + *
>> + * 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.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, write to the Free Software
>> + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
>> + */
>> +
>> +#include<linux/device.h>
>> +#include<linux/eventfd.h>
>> +#include<linux/interrupt.h>
>> +#include<linux/iommu.h>
>> +#include<linux/module.h>
>> +#include<linux/mutex.h>
>> +#include<linux/notifier.h>
>> +#include<linux/pm_runtime.h>
>> +#include<linux/slab.h>
>> +#include<linux/types.h>
>> +#include<linux/uaccess.h>
>> +#include<linux/vfio.h>
>> +
>> +#define DRIVER_VERSION  "0.1"
>> +#define DRIVER_AUTHOR   "Antonios Motakis<a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>"
>> +#define DRIVER_DESC     "VFIO Device Tree devices - User Level meta-driver"
>> +
>> +struct vfio_platform_device {
>> +	struct platform_device	*pdev;
>> +};
>> +
>> +static void vfio_platform_release(void *device_data) {
>> +	module_put(THIS_MODULE);
>> +}
>> +
>> +static int vfio_platform_open(void *device_data) {
>> +	if (!try_module_get(THIS_MODULE))
>> +		return -ENODEV;
>> +
>> +	return 0;
>> +}
>> +
>> +static long vfio_platform_ioctl(void *device_data,
>> +			   unsigned int cmd, unsigned long arg) {
>> +	struct vfio_platform_device *vdev = device_data;
>> +	unsigned long minsz;
>> +
>> +	if (cmd == VFIO_DEVICE_GET_INFO) {
>> +		struct vfio_device_info info;
>> +
>> +		minsz = offsetofend(struct vfio_device_info, num_irqs);
>> +
>> +		if (copy_from_user(&info, (void __user *)arg, minsz))
>> +			return -EFAULT;
>> +
>> +		if (info.argsz<  minsz)
>> +			return -EINVAL;
>> +
>> +		info.flags = VFIO_DEVICE_FLAGS_PLATFORM;
>> +		info.num_regions = 0;
>> +		info.num_irqs = 0;
>> +
>> +		return copy_to_user((void __user *)arg,&info, minsz);
>> +
>> +	} else if (cmd == VFIO_DEVICE_GET_REGION_INFO)
>> +		return -EINVAL;
>> +
>> +	else if (cmd == VFIO_DEVICE_GET_IRQ_INFO)
>> +		return -EINVAL;
>> +
>> +	else if (cmd == VFIO_DEVICE_SET_IRQS)
>> +		return -EINVAL;
>> +
>> +	else if (cmd == VFIO_DEVICE_RESET)
>> +		return -EINVAL;
>> +
>> +	return -ENOTTY;
>> +}
>> +
>> +static ssize_t vfio_platform_read(void *device_data, char __user *buf,
>> +			     size_t count, loff_t *ppos)
>> +{
>> +	return 0;
>> +}
>> +
>> +static ssize_t vfio_platform_write(void *device_data, const char __user *buf,
>> +			      size_t count, loff_t *ppos)
>> +{
>> +	return 0;
>> +}
>> +
>> +static int vfio_platform_mmap(void *device_data, struct vm_area_struct
>> +*vma) {
>> +	return -EINVAL;
>> +}
>> +
>> +static const struct vfio_device_ops vfio_platform_ops = {
>> +	.name		= "vfio-platform",
>> +	.open		= vfio_platform_open,
>> +	.release	= vfio_platform_release,
>> +	.ioctl		= vfio_platform_ioctl,
>> +	.read		= vfio_platform_read,
>> +	.write		= vfio_platform_write,
>> +	.mmap		= vfio_platform_mmap,
>> +};
>> +
>> +static int vfio_platform_probe(struct platform_device *pdev) {
>> +	struct vfio_platform_device *vdev;
>> +	struct iommu_group *group;
>> +	int ret;
>> +
>> +	group = iommu_group_get(&pdev->dev);
>> +	if (!group) {
>> +		pr_err("VFIO: No IOMMU group for device %s\n", pdev->name);
>> +		return -EINVAL;
>> +	}
>> +
>> +	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
>> +	if (!vdev) {
>> +		iommu_group_put(group);
>> +		return -ENOMEM;
>> +	}
>> +
>> +	vdev->pdev = pdev;
>> +
>> +	ret = vfio_add_group_dev(&pdev->dev,&vfio_platform_ops, vdev);
>> +	if (ret) {
>> +		iommu_group_put(group);
>> +		kfree(vdev);
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int vfio_platform_remove(struct platform_device *pdev) {
>> +	struct vfio_platform_device *vdev;
>> +
>> +	vdev = vfio_del_group_dev(&pdev->dev);
>> +	if (!vdev)
>> +		return -EINVAL;
>> +
>> +	iommu_group_put(pdev->dev.iommu_group);
>> +	kfree(vdev);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id vfio_platform_match[] = {
>> +	/* Before this series can be applied, we shall implement a better
>> +	 * mechanism to bind the module to any device. For now add the
>> +	 * compatible property to the dtb of the devices we want to use. */
>> +	{
>> +		.compatible = "vfio",
>> +	},
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, vfio_platform_match);
>> +
>> +static struct platform_driver vfio_platform_driver = {
>> +	.probe		= vfio_platform_probe,
>> +	.remove		= vfio_platform_remove,
>> +	.driver	= {
>> +		.name	= "vfio-platform",
>> +		.owner	= THIS_MODULE,
>> +		.of_match_table = vfio_platform_match,
>> +	},
>> +};
>> +
>> +module_platform_driver(vfio_platform_driver);
>> +
>> +MODULE_VERSION(DRIVER_VERSION);
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR(DRIVER_AUTHOR);
>> +MODULE_DESCRIPTION(DRIVER_DESC);
>> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index
>> 284ff24..8d7434d 100644
>> --- a/include/uapi/linux/vfio.h
>> +++ b/include/uapi/linux/vfio.h
>> @@ -147,6 +147,7 @@ struct vfio_device_info {
>>   	__u32	flags;
>>   #define VFIO_DEVICE_FLAGS_RESET	(1<<  0)	/* Device supports reset */
>>   #define VFIO_DEVICE_FLAGS_PCI	(1<<  1)	/* vfio-pci device */
>> +#define VFIO_DEVICE_FLAGS_PLATFORM (1<<  2)	/* vfio-platform device */
>>   	__u32	num_regions;	/* Max region index + 1 */
>>   	__u32	num_irqs;	/* Max IRQ index + 1 */
>>   };
>> --
>> 1.8.1.2
>>
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