On 2023/9/27 09:08, Tian, Kevin wrote:
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.
ack.
--
Regards,
Yi Liu
