> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Wednesday, September 27, 2023 12:29 AM
>
> On Tue, Sep 26, 2023 at 06:37:55AM +0000, Tian, Kevin wrote:
> > > From: Robin Murphy <robin.murphy@xxxxxxx>
> > > Sent: Friday, September 22, 2023 5:48 PM
> > >
> > > I could go on enjoying myself, but basically yeah, "default" can't be a
> > > type in itself (at best it would be a meta-type which could be
> > > requested, such that it resolves to some real type to actually
> > > allocate), so a good name should reflect what the type functionally
> > > *means* to the user. IIUC the important distinction is that it's an
> > > abstract kernel-owned pagetable for the user to indirectly control via
> > > the API, rather than one it owns and writes directly (and thus has to be
> > > in a specific agreed format).
> > >
> >
> > IOMMU_HWPT_TYPE_KERNEL then?
> >
> > IOMMU_HWPT_TYPE_GENERIC also doesn't sound a straight word.
>
> At the end of the day this enum is the type tag for:
>
> struct iommu_hwpt_alloc {
> __u32 size;
> __u32 pt_id;
> __u32 out_hwpt_id;
> __u32 __reserved;
> + __u32 hwpt_type;
> + __u32 data_len;
> + __aligned_u64 data_uptr;
> };
>
> That pointer.
>
> IOMMU_HWPT_ALLOC_DATA_NONE = 0
> IOMMU_HWPT_ALLOC_DATA_INTEL_VTD
> IOMMU_HWPT_ALLOC_DATA_ARM_SMMUV3
>
> etc?
>
> DATA_NONE requires data_len == 0
>
Looks good. Probably hwpt_type can be also renamed to data_type
to better match this interpretation.
