Re: [PATCH v2 1/6] vfio: implement iommu driver capabilities with an enum

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

On Mon, 2014-10-27 at 19:05 +0100, Antonios Motakis wrote:
> Currently a VFIO driver's IOMMU capabilities are encoded as a series of
> numerical defines. Replace this with an enum for future maintainability.
> 
> Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
> ---
>  include/uapi/linux/vfio.h | 21 ++++++++++-----------
>  1 file changed, 10 insertions(+), 11 deletions(-)
> 
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 6612974..1e39842 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -19,19 +19,18 @@
>  
>  /* Kernel & User level defines for VFIO IOCTLs. */
>  
> -/* Extensions */
> -
> -#define VFIO_TYPE1_IOMMU		1
> -#define VFIO_SPAPR_TCE_IOMMU		2
> -#define VFIO_TYPE1v2_IOMMU		3
>  /*
> - * IOMMU enforces DMA cache coherence (ex. PCIe NoSnoop stripping).  This
> - * capability is subject to change as groups are added or removed.
> + * Capabilities exposed by the VFIO IOMMU driver. Some capabilities are subject
> + * to change as groups are added or removed.
>   */
> -#define VFIO_DMA_CC_IOMMU		4
> -
> -/* Check if EEH is supported */
> -#define VFIO_EEH			5
> +enum vfio_iommu_cap {
> +	VFIO_TYPE1_IOMMU	= 1,
> +	VFIO_SPAPR_TCE_IOMMU	= 2,
> +	VFIO_TYPE1v2_IOMMU	= 3,
> +	VFIO_DMA_CC_IOMMU	= 4, /* IOMMU enforces DMA cache coherence
> +					(ex. PCIe NoSnoop stripping) */
> +	VFIO_EEH		= 5, /* Check if EEH is supported */
> +};

Your code base is a little out of date, you're missing:

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/include/uapi/linux/vfio.h?id=f5c9ecebaf2a2c9381973798e389cc019dd983e0

I think the logic looks ok in the rest, but you'll need to use index 7
and the above commit touched the type1 c file as well so you may need to
adjustment there too.  Thanks,

Alex
>  
>  /*
>   * The IOCTL interface is designed for extensibility by embedding the