Re: [PATCH 1/6] x86/virt/tdx: Wrap TDH.SYS.CONFIG/UPDATE operations in helpers

[Nikolay Borisov]

On 8/21/26 06:29, Xu Yilun wrote:
> As part of the TDX module initialization, the kernel configures the TDX
> module with several information, such as TDX-usable memory regions
> (TDMRs) and the global KeyID for protecting TDX metadata. During the
> configuration, the kernel does 2 operations: constructing kernel data
> types for the SEAMCALL leaf arguments and turning these data types into
> u64's according to TDX ABI.
>
> Both operations are implemented in one function - config_tdx_module().
> This blurs the boundary between kernel managed structures and TDX ABI
> definitions. Moreover, future kernel change will need to add more
> nuances mandated by TDX ABI, such as setting the TDH.SYS.CONFIG leaf
> version to allow configuring add-on features. Keeping these operations
> tangled would further clutter the code.
>
> Just like other SEAMCALL leaf helpers, wrap the invocation of
> TDH.SYS.CONFIG in a helper. Introduce a more descriptive kernel data
> type for the physical address array of TDMR information. This data type
> is similar to struct seamldr_params in that it is the container of the
> PA array layout which is an in-memory ABI. So the previous u64 * type
> for the array is not wrong, but a named structure provides better type
> safety and self-documentation. Use the data type as the argument of the
> TDH.SYS.CONFIG helper.
>
> Future kernel change will also need to set the TDH.SYS.UPDATE leaf
> version for the same purpose. Add a similar helper to prepare for the
> change.
>
> Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxxxxxxxx>

Reviewed-by: Nikolay Borisov <nik.borisov@xxxxxxxx>