Re: [RFC PATCH 15/15] x86/virt/tdx: Enable TDX Quoting extension

[Xu Yilun <yilun.xu@linux.intel.com>]

> > diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
> > index 10aff23cd01f..524a14c01aa6 100644
> > --- a/arch/x86/virt/vmx/tdx/tdx.h
> > +++ b/arch/x86/virt/vmx/tdx/tdx.h
> > @@ -58,7 +58,8 @@
> >   #define TDH_PHYMEM_CACHE_WB		40
> >   #define TDH_PHYMEM_PAGE_WBINVD		41
> >   #define TDH_VP_WR			43
> > -#define TDH_SYS_CONFIG			45
> > +#define TDH_SYS_CONFIG_V0		45
> 
> Is it necessary to add _Vx macros when multiple versions can co-exist?
> 
> Just wondering if it would be cleaner in the following way?
> 
> - Leave the macros set at the current (non-deprecated) baseline version.
> - Select vX using SEAMCALL_LEAF_VER() in config_tdx_module() when a vX feature
>   is enabled.

My perference is to have the most simple rule for the unversioned macro.
And leave all workarounds to _Vx macros, they will eventually been
removed or deprecated.

Anyway this patch is not expected to merge with this series, maybe we
will have a public release with V1 supported when it is to be merged,
then we don't have to make such a hard choice.

> 
> u64 seamcall_fn = TDH_SYS_CONFIG;
> ...
> if (tdx_sysinfo.features.tdx_features0 & TDX_FEATURES0_QUOTE) {
> ...
>     seamcall_fn = SEAMCALL_LEAF_VER(TDH_SYS_CONFIG, 1);