Re: [PATCH] x86/virt/tdx: Warn on !4K level in tdh_mem_page_aug()

[Sean Christopherson <seanjc@google.com>]

On Tue, Aug 25, 2026, Rick P Edgecombe wrote:
> On Tue, 2026-08-25 at 10:55 +0800, Yan Zhao wrote:
> > Do not drop the "level" parameter instead, as it will be needed once huge
> > page support is added.
> 
> TDX and coco has so many plans for the future. An abnormal amount of concurrent
> thinking. I think everyone agrees we need to wrangle it by doing things
> iteratively, and cheating when it comes to uABI.
> 
> Since we have TDX huge pages coming so soon, it seems ok to leave it. But I just
> wanted to say having the level arg here originally was wrong. So this should not
> be precedent for pre-enabling of things years in the future.

Eh, I would argue that in this particular case, including @level was ok from a
process perspective, the main issue is the implementation was buggy.  Which is
very arguably _because_ there was no user to validate the code, but given all the
pre-existing KVM MMU code at play, at some point we'd have to insert code to say
"hugepages aren't supported".  E.g. in this specific case, assuming PG_LEVEL_4K
could have been just as bad as having a partially-dead @level.

But nitpicking aside, +1 to not building out unused, untestable infrastructure.