Re: [PATCH 2/4] vfio: vfio_iommu_type1: Define VFIO_IOMMU_INFO_CAPABILITIES

[Pierre Morel]

On 16/05/2019 20:31, Alex Williamson wrote:
> On Fri, 10 May 2019 10:22:33 +0200
> Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
>
> > To use the VFIO_IOMMU_GET_INFO to retrieve IOMMU specific information,
> > we define a new flag VFIO_IOMMU_INFO_CAPABILITIES in the
> > vfio_iommu_type1_info structure and the associated capability
> > information block.
> >
> > Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> > ---
> >   include/uapi/linux/vfio.h | 10 ++++++++++
> >   1 file changed, 10 insertions(+)
> >
> > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> > index 8f10748..8f68e0f 100644
> > --- a/include/uapi/linux/vfio.h
> > +++ b/include/uapi/linux/vfio.h
> > @@ -715,6 +715,16 @@ struct vfio_iommu_type1_info {
> >   	__u32	flags;
> >   #define VFIO_IOMMU_INFO_PGSIZES (1 << 0)	/* supported page sizes info */
> >   	__u64	iova_pgsizes;		/* Bitmap of supported page sizes */
> > +#define VFIO_IOMMU_INFO_CAPABILITIES (1 << 1)  /* support capabilities info */
> > +	__u64   cap_offset;     /* Offset within info struct of first cap */
> > +};
> > +
> > +#define VFIO_IOMMU_INFO_CAP_QFN		1
> > +#define VFIO_IOMMU_INFO_CAP_QGRP	2
>
> Descriptions?
>
> > +
> > +struct vfio_iommu_type1_info_block {
> > +	struct vfio_info_cap_header header;
> > +	__u32 data[];
> >   };
> >   
> >   #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12)
>
> This is just a blob of data, what's the API?  How do we revision it?
> How does the user know how to interpret it?  Dumping kernel internal
> structures out to userspace like this is not acceptable, define a user
> API. Thanks,
>
> Alex

Thanks Alex for the comments.
I will add the decription and the user API for the next iteration.

Regards,
Pierre




--
Pierre Morel
Linux/KVM/QEMU in BÃblingen - Germany