Subject: Re: [PATCH kernel v4 18/19] vfio_pci: Allow regions to add own capabilities

From: Alex Williamson <[email-masked]>
Date: Mon, 10 Dec 2018 17:10:16 -0700

On Fri, 23 Nov 2018 16:53:03 +1100
Alexey Kardashevskiy <[email-masked]> wrote:

> VFIO regions already support region capabilities with a limited set of
> fields. However the subdriver might have to report to the userspace
> additional bits.
> 
> This adds an add_capability() hook to vfio_pci_regops.
> 
> Signed-off-by: Alexey Kardashevskiy <[email-masked]>
> ---
> Changes:
> v3:
> * removed confusing rationale for the patch, the next patch makes
> use of it anyway
> ---
>  drivers/vfio/pci/vfio_pci_private.h | 3 +++
>  drivers/vfio/pci/vfio_pci.c         | 6 ++++++
>  2 files changed, 9 insertions(+)

Acked-by: Alex Williamson <[email-masked]>

> diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
> index 86aab05..93c1738 100644
> --- a/drivers/vfio/pci/vfio_pci_private.h
> +++ b/drivers/vfio/pci/vfio_pci_private.h
> @@ -62,6 +62,9 @@ struct vfio_pci_regops {
>  	int	(*mmap)(struct vfio_pci_device *vdev,
>  			struct vfio_pci_region *region,
>  			struct vm_area_struct *vma);
> +	int	(*add_capability)(struct vfio_pci_device *vdev,
> +				  struct vfio_pci_region *region,
> +				  struct vfio_info_cap *caps);
>  };
>  
>  struct vfio_pci_region {
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index 4a6f7c0..6cb70cf 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -763,6 +763,12 @@ static long vfio_pci_ioctl(void *device_data,
>  			if (ret)
>  				return ret;
>  
> +			if (vdev->region[i].ops->add_capability) {
> +				ret = vdev->region[i].ops->add_capability(vdev,
> +						&vdev->region[i], &caps);
> +				if (ret)
> +					return ret;
> +			}
>  		}
>  		}
>