Re: [PATCH v9 04/19] vfio: amba: VFIO support for AMBA devices

[Alex Williamson <alex.williamson@redhat.com>]

On Mon, 2014-10-27 at 19:07 +0100, Antonios Motakis wrote:
> Add support for discovering AMBA devices with VFIO and handle them
> similarly to Linux platform devices.
> 
> Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
> ---
>  drivers/vfio/platform/vfio_amba.c | 116 ++++++++++++++++++++++++++++++++++++++
>  include/uapi/linux/vfio.h         |   1 +
>  2 files changed, 117 insertions(+)
>  create mode 100644 drivers/vfio/platform/vfio_amba.c
> 
> diff --git a/drivers/vfio/platform/vfio_amba.c b/drivers/vfio/platform/vfio_amba.c
> new file mode 100644
> index 0000000..cf61324
> --- /dev/null
> +++ b/drivers/vfio/platform/vfio_amba.c
> @@ -0,0 +1,116 @@
> +/*
> + * Copyright (C) 2013 - Virtual Open Systems
> + * Author: Antonios Motakis <a.motakis@virtualopensystems.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.
> + *
> + * 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/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/irq.h>
> +#include <linux/amba/bus.h>
> +
> +#include "vfio_platform_private.h"
> +
> +#define DRIVER_VERSION  "0.9"
> +#define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@virtualopensystems.com>"
> +#define DRIVER_DESC     "VFIO for AMBA devices - User Level meta-driver"
> +
> +/* probing devices from the AMBA bus */
> +
> +static struct resource *get_amba_resource(struct vfio_platform_device *vdev,
> +						int i)
> +{
> +	struct amba_device *adev = (struct amba_device *) vdev->opaque;
> +
> +	if (i == 0)
> +		return &adev->res;
> +
> +	return NULL;
> +}
> +
> +static int get_amba_irq(struct vfio_platform_device *vdev, int i)
> +{
> +	struct amba_device *adev = (struct amba_device *) vdev->opaque;
> +
> +	if (i < AMBA_NR_IRQS)
> +		return adev->irq[i];
> +
> +	return 0;
> +}
> +
> +static int vfio_amba_probe(struct amba_device *adev, const struct amba_id *id)
> +{
> +
> +	struct vfio_platform_device *vdev;
> +	int ret;
> +
> +	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
> +	if (!vdev)
> +		return -ENOMEM;
> +
> +	vdev->opaque = (void *) adev;
> +	vdev->name = "vfio-amba-dev";

You need to actually allocate some memory here with something like
kasprintf.  Don't forget to free it on the error and remove path.

> +	vdev->flags = VFIO_DEVICE_FLAGS_AMBA;
> +	vdev->get_resource = get_amba_resource;
> +	vdev->get_irq = get_amba_irq;
> +
> +	ret = vfio_platform_probe_common(vdev, &adev->dev);
> +	if (ret)
> +		kfree(vdev);
> +
> +	return ret;
> +}
> +
> +static int vfio_amba_remove(struct amba_device *adev)
> +{
> +	struct vfio_platform_device *vdev;
> +
> +	vdev = vfio_platform_remove_common(&adev->dev);
> +	if(vdev) {
> +		kfree(vdev);
> +		return 0;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static struct amba_id pl330_ids[] = {
> +	{ 0, 0 },
> +};
> +
> +MODULE_DEVICE_TABLE(amba, pl330_ids);
> +
> +static struct amba_driver vfio_amba_driver = {
> +	.probe = vfio_amba_probe,
> +	.remove = vfio_amba_remove,
> +	.id_table = pl330_ids,
> +	.drv = {
> +		.name = "vfio-amba",
> +		.owner = THIS_MODULE,
> +	},
> +};
> +
> +module_amba_driver(vfio_amba_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 9db1056..92469e0 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -158,6 +158,7 @@ struct vfio_device_info {
>  #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 */
> +#define VFIO_DEVICE_FLAGS_AMBA  (1 << 3)	/* vfio-amba device */
>  	__u32	num_regions;	/* Max region index + 1 */
>  	__u32	num_irqs;	/* Max IRQ index + 1 */
>  };