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

[Dave Hansen <dave.hansen@intel.com>]

On 7/20/26 23:49, Peter Fang wrote:
...
>> This is all talking about post-quantum-crypto and all that fancy stuff.
>>
>> Isn't the important part here that the old TDX module ABI had static
>> quote sizes and now they're dynamic? Now, the reason it changed is all
>> the fancy stuff.
>>
>> But the ABI changed. Right?
> 
> Ah yes... I should call out that the size of
> /sys/kernel/config/tsm/report/$name/outblob will no longer be fixed.
> I'll update this. Thanks.

No. I mean the TDX Module ABI changed.

That's why we need new kernel patches.
>> The host may be untrusted, but it's also a critical part of the system.
>> Are we sure we want to be completely quiet?
>>
>> I used to see little dmesg warnings about TCP window shenanigans from
>> random systems on the Internet. Maybe that's not how we do things today,
>> but if a random dude on the Internet can spew one line to dmesg, is it
>> that crazy that a bad VMM be able to spew a warning?
> 
> That makes sense... I actually argued with AI about this but it kept
> saying this is kind of like DoSing the guest. But thinking about it
> more, tainting the guest is probably the right thing to do... At least
> the guest sees a big splat about why attestation is failing. I'll remove
> the __GFP_NOWARN. Thanks.

This does seem like the kind of high-level TDX policy that we all need
to be aligned on and probably document somewhere. The basic question is
whether a TDX guest should be quiet or verbose in the face of host
malfunction or malfeasance.

Kirill and Rick, what do you think?