Re: [PATCH v9 10/19] vfio/platform: return IRQ info

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

On Mon, 2014-10-27 at 19:07 +0100, Antonios Motakis wrote:
> Return information for the interrupts exposed by the device.
> This patch extends VFIO_DEVICE_GET_INFO with the number of IRQs
> and enables VFIO_DEVICE_GET_IRQ_INFO.
> 
> Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
> ---
>  drivers/vfio/platform/Makefile                |  2 +-
>  drivers/vfio/platform/vfio_platform_common.c  | 31 ++++++++++++--
>  drivers/vfio/platform/vfio_platform_irq.c     | 59 +++++++++++++++++++++++++++
>  drivers/vfio/platform/vfio_platform_private.h | 10 +++++
>  4 files changed, 97 insertions(+), 5 deletions(-)
>  create mode 100644 drivers/vfio/platform/vfio_platform_irq.c
> 
> diff --git a/drivers/vfio/platform/Makefile b/drivers/vfio/platform/Makefile
> index 1957170..81de144 100644
> --- a/drivers/vfio/platform/Makefile
> +++ b/drivers/vfio/platform/Makefile
> @@ -1,5 +1,5 @@
>  
> -vfio-platform-y := vfio_platform.o vfio_platform_common.o
> +vfio-platform-y := vfio_platform.o vfio_platform_common.o vfio_platform_irq.o
>  
>  obj-$(CONFIG_VFIO_PLATFORM) += vfio-platform.o
>  
> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> index aeaaec9..5f2c205 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -105,6 +105,7 @@ static void vfio_platform_release(void *device_data)
>  
>  	if (!(--vdev->refcnt)) {
>  		vfio_platform_regions_cleanup(vdev);
> +		vfio_platform_irq_cleanup(vdev);
>  	}
>  
>  	mutex_unlock(&driver_lock);
> @@ -126,6 +127,10 @@ static int vfio_platform_open(void *device_data)
>  		ret = vfio_platform_regions_init(vdev);
>  		if (ret)
>  			goto err_reg;
> +
> +		ret = vfio_platform_irq_init(vdev);
> +		if (ret)
> +			goto err_irq;
>  	}
>  
>  	vdev->refcnt++;
> @@ -133,6 +138,8 @@ static int vfio_platform_open(void *device_data)
>  	mutex_unlock(&driver_lock);
>  	return 0;
>  
> +err_irq:
> +	vfio_platform_regions_cleanup(vdev);
>  err_reg:
>  	mutex_unlock(&driver_lock);
>  	module_put(THIS_MODULE);
> @@ -158,7 +165,7 @@ static long vfio_platform_ioctl(void *device_data,
>  
>  		info.flags = vdev->flags;
>  		info.num_regions = vdev->num_regions;
> -		info.num_irqs = 0;
> +		info.num_irqs = vdev->num_irqs;
>  
>  		return copy_to_user((void __user *)arg, &info, minsz);
>  
> @@ -183,10 +190,26 @@ static long vfio_platform_ioctl(void *device_data,
>  
>  		return copy_to_user((void __user *)arg, &info, minsz);
>  
> -	} else if (cmd == VFIO_DEVICE_GET_IRQ_INFO)
> -		return -EINVAL;
> +	} else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
> +		struct vfio_irq_info info;
> +
> +		minsz = offsetofend(struct vfio_irq_info, count);
> +
> +		if (copy_from_user(&info, (void __user *)arg, minsz))
> +			return -EFAULT;
> +
> +		if (info.argsz < minsz)
> +			return -EINVAL;
> +
> +		if (info.index >= vdev->num_irqs)
> +			return -EINVAL;
> +
> +		info.flags = vdev->irqs[info.index].flags;
> +		info.count = vdev->irqs[info.index].count;
> +
> +		return copy_to_user((void __user *)arg, &info, minsz);
>  
> -	else if (cmd == VFIO_DEVICE_SET_IRQS)
> +	} else if (cmd == VFIO_DEVICE_SET_IRQS)
>  		return -EINVAL;
>  
>  	else if (cmd == VFIO_DEVICE_RESET)
> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
> new file mode 100644
> index 0000000..d99c71c
> --- /dev/null
> +++ b/drivers/vfio/platform/vfio_platform_irq.c
> @@ -0,0 +1,59 @@
> +/*
> + * VFIO platform devices interrupt handling
> + *
> + * 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/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/platform_device.h>
> +#include <linux/irq.h>
> +
> +#include "vfio_platform_private.h"
> +
> +int vfio_platform_irq_init(struct vfio_platform_device *vdev)
> +{
> +	int cnt = 0, i;
> +
> +	while (vdev->get_irq(vdev, cnt) > 0)

For platform devices this is just a wrapper around platform_get_irq(),
which sort of seems like it can return 0 as a valid irq.  Am I wrong
about that?  If 0 can be valid, AMBA would need to update it's error
return value too.

> +		cnt++;
> +
> +	vdev->irqs = kcalloc(cnt, sizeof(struct vfio_platform_irq), GFP_KERNEL);
> +	if (!vdev->irqs)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < cnt; i++) {
> +		vdev->irqs[i].flags = 0;
> +		vdev->irqs[i].count = 1;
> +	}
> +
> +	vdev->num_irqs = cnt;
> +
> +	return 0;
> +}
> +
> +void vfio_platform_irq_cleanup(struct vfio_platform_device *vdev)
> +{
> +	vdev->num_irqs = 0;
> +	kfree(vdev->irqs);
> +}
> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
> index 1f251b2..3a29a72 100644
> --- a/drivers/vfio/platform/vfio_platform_private.h
> +++ b/drivers/vfio/platform/vfio_platform_private.h
> @@ -24,6 +24,11 @@
>  #define VFIO_PLATFORM_INDEX_TO_OFFSET(index)	\
>  	((u64)(index) << VFIO_PLATFORM_OFFSET_SHIFT)
>  
> +struct vfio_platform_irq {
> +	u32			flags;
> +	u32			count;
> +};
> +
>  struct vfio_platform_region {
>  	u64			addr;
>  	resource_size_t		size;
> @@ -37,6 +42,8 @@ struct vfio_platform_region {
>  struct vfio_platform_device {
>  	struct vfio_platform_region	*regions;
>  	u32				num_regions;
> +	struct vfio_platform_irq	*irqs;
> +	u32				num_irqs;
>  	int				refcnt;
>  
>  	/*
> @@ -56,4 +63,7 @@ extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,
>  extern struct vfio_platform_device *vfio_platform_remove_common
>  				     (struct device *dev);
>  
> +extern int vfio_platform_irq_init(struct vfio_platform_device *vdev);
> +extern void vfio_platform_irq_cleanup(struct vfio_platform_device *vdev);
> +
>  #endif /* VFIO_PLATFORM_PRIVATE_H */