Re: [PATCH v8 02/18] vfio: platform: probe to devices on the platform bus

From: Alex Williamson
Date: Tue Oct 21 2014 - 12:18:12 EST


On Mon, 2014-10-13 at 15:10 +0200, Antonios Motakis wrote:
> Driver to bind to Linux platform devices, and callbacks to discover their
> resources to be used by the main VFIO PLATFORM code.
>
> Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/vfio/platform/vfio_platform.c | 107 ++++++++++++++++++++++++++++++++++
> include/uapi/linux/vfio.h | 1 +
> 2 files changed, 108 insertions(+)
> create mode 100644 drivers/vfio/platform/vfio_platform.c
>
> diff --git a/drivers/vfio/platform/vfio_platform.c b/drivers/vfio/platform/vfio_platform.c
> new file mode 100644
> index 0000000..baeb7da
> --- /dev/null
> +++ b/drivers/vfio/platform/vfio_platform.c
> @@ -0,0 +1,107 @@
> +/*
> + * Copyright (C) 2013 - Virtual Open Systems
> + * Author: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
> + *
> + * 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.
> + */
> +
> +#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>
> +#include <linux/io.h>
> +#include <linux/platform_device.h>
> +#include <linux/irq.h>
> +
> +#include "vfio_platform_private.h"
> +
> +#define DRIVER_VERSION "0.8"
> +#define DRIVER_AUTHOR "Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>"
> +#define DRIVER_DESC "VFIO for platform devices - User Level meta-driver"
> +
> +/* probing devices from the linux platform bus */
> +
> +static struct resource *get_platform_resource(struct vfio_platform_device *vdev,
> + int num)
> +{
> + struct platform_device *dev = (struct platform_device *) vdev->opaque;
> + int i;
> +
> + for (i = 0; i < dev->num_resources; i++) {
> + struct resource *r = &dev->resource[i];
> +
> + if (resource_type(r) & (IORESOURCE_MEM|IORESOURCE_IO)) {
> + num--;
> +
> + if (!num)
> + return r;

Has this been tested? What happens when we call this with num = 0?

> + }
> + }
> + return NULL;
> +}
> +
> +static int get_platform_irq(struct vfio_platform_device *vdev, int i)
> +{
> + struct platform_device *pdev = (struct platform_device *) vdev->opaque;
> +
> + return platform_get_irq(pdev, i);
> +}
> +
> +
> +static int vfio_platform_probe(struct platform_device *pdev)
> +{
> + struct vfio_platform_device *vdev;
> + int ret;
> +
> + vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
> + if (!vdev)
> + return -ENOMEM;
> +
> + vdev->opaque = (void *) pdev;
> + vdev->name = pdev->name;
> + vdev->flags = VFIO_DEVICE_FLAGS_PLATFORM;
> + vdev->get_resource = get_platform_resource;
> + vdev->get_irq = get_platform_irq;
> +
> + ret = vfio_platform_probe_common(vdev, &pdev->dev);
> + if (ret)
> + kfree(vdev);
> +
> + return ret;
> +}
> +
> +static int vfio_platform_remove(struct platform_device *pdev)
> +{
> + return vfio_platform_remove_common(&pdev->dev);
> +}
> +
> +static struct platform_driver vfio_platform_driver = {
> + .probe = vfio_platform_probe,
> + .remove = vfio_platform_remove,
> + .driver = {
> + .name = "vfio-platform",
> + .owner = THIS_MODULE,
> + },
> +};
> +
> +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 111b5e8..aca6d3e 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -158,6 +158,7 @@ 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 */
> };



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