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

From: Alex Williamson
Date: Fri Oct 31 2014 - 16:04:31 EST


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@xxxxxxxxxxxxxxxxxxxxxx>
> ---
> 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Your code base is a little out of date, you're missing: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



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