Re: [PATCH v2 2/2] virt: tdx-guest: Allocate Quote buffer dynamically

[Peter Fang <peter.fang@intel.com>]

On Wed, Jul 22, 2026 at 01:00:35PM +0100, Kiryl Shutsemau wrote:
> On Tue, Jul 21, 2026 at 04:43:57PM +0000, Edgecombe, Rick P wrote:
> > BUT, is this number coming from the untrusted host or the TDX module? I cant
> > find TDCS_QUOTE_MAX_SIZE in the docs.
> 
> I cannot find it too. Peter, any pointers where it is documented
> publicly?

Gosh sorry I missed this. Turns out it was not fully published due to
some internal error. Yikes.

This metadata field is documented in "Intel TDX Module Extension for
Quoting", Section "TD-Scope Metadata" [1]. But the encoding of this
field got missed in the June 2026 release of "Intel TDX Module ABI
Definitions". I just escalated this. I'll come back and give an update
once it's fixed... Apologies for the oversight.

[1] https://cdrdv2.intel.com/v1/dl/getContent/874303

> 
> > If it is coming from the TDX module then
> > we are not talking about security considerations at all. It's just a functional
> > "do you want to know if things are failing". Not sure why this one would be
> > special in that regard. If we think it will fail so often that we don't want a
> > warning, then we probably need another solution.
> 
> Silent makes no sense to me. We are talking about attestation. If
> attestation fails the TD is functionally dead: it cannot obtain secrets.

Yep. I'll remove __GFP_NOWARN in the next version. Thanks.

> 
> -- 
>   Kiryl Shutsemau / Kirill A. Shutemov