Re: [PATCH v3 0/4] tdx-guest: Make Quote buffer size dynamic

[Peter Fang]

On Wed, Jul 29, 2026 at 02:21:12PM -0700, Edgecombe, Rick P wrote:
> On Wed, 2026-07-29 at 05:29 -0700, Peter Fang wrote:
> > Problem
> > =======
> > 
> > The fixed-size Quote buffer approach is not sustainable. As
> > cryptographic algorithms evolve, TD Quote sizes also grow. A previous
> > commit [2] increased the guest driver's fixed-size Quote buffer to 128
> > KB to accommodate DICE Quotes, but it may still be insufficient when
> > those Quotes use post-quantum cryptography (PQC). PQC certificate chains
> > are roughly 10x-15x larger than conventional ones, which can increase
> > Quote sizes significantly.
> 
> For the DICE host changes, the reason given for why the host side quote
> operation is TD scoped was to avoid changing the guest by increasing the report
> size. But actually, as this coverletter points out, the guest buffer sizes do
> get changed. So I think we should pause this series until we sort out the

This thread has led to a lot of great discussion, and I think perhaps we
can resume reviewing this series? The main open topics now seem to be
the guest report and potential alternatives to GetQuote, but none of
them change the fact that the quote size is growing as crypto stuff
evolves... So this series applies to all the options on the table right
now.

> inconsistencies in the reasoning. Depending, we may want to circle back with KVM
> folks on what the options actually are for the DICE quote operation.