Re: [PATCH 01/15] x86/virt/tdx: Read global metadata for TDX Module Extensions

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

On Wed, May 27, 2026 at 10:17:36AM -0700, Sohil Mehta wrote:
> On 5/27/2026 12:11 AM, Xu Yilun wrote:
> 
> >>> +struct tdx_sys_info_ext {
> >>> +	u16 memory_pool_required_pages;
> >>> +	u8 ext_required;
> >>
> >> The name ext_required seems like a boolean. It is also used like a
> >> boolean later.
> >> 	if (!tdx_sysinfo.ext.ext_required)
> >> 		return 0;
> >>
> >> But, IIUC, is it actually a mask that lists any feature that needs
> > 
> > No it is just a bool about Extentions needs to be initialized or not.
> > 
> How does the kernel know which features need Extensions? Is there any
> hardware enumeration or the kernel just keeps a static list?

There is no HW enumeration, mm... seems this is an important reason that
we don't delay the Extensions enabling, kernel doesn't have to keep in
mind which features need Extensions.