Re: [PATCH v4 0/4] tdx-guest: Make Quote buffer size dynamic

[Peter Fang]

On Tue, Sep 15, 2026 at 09:11:31AM -0700, Edgecombe, Rick P wrote:
> On Tue, 2026-09-15 at 07:07 -0700, Sean Christopherson wrote:
> > Where is the breakdown of why "generating quotes entirely within the TDX-
> > Module is too complex" I was promised?
> 
> Several of us have been investigating this. It turns out there was a discussion
> in the past where several complex but solvable problems were discussed. During
> the discussion, a larger problem was identified. But, and you might find this
> funny given your preference for recording everything on the list, the larger
> problem that got identified was not written down. We've been unable to reproduce
> it, so we're currently writing up what we have.
> 
> And in case there is any confusion, this series here is orthogonal to the TDG
> get quote question. The buffer needs to be expanded for PQC stuff in any case.

Just to be extra clear... Patch 4 added this:

        if (quote_size)
                /* The reported size does not include the buffer header */
                len = TDX_QUOTE_BUF_LEN(quote_size);

And it is about adding the GHCI header to the buffer size. So if there
is a design change and this header is no longer needed, this line could
become redundant. The macro might cause the driver to allocate more
memory than needed (up to one page), so things should still work and we
could fix this up later.