Re: [PATCH] virt: tdx-guest: Deprecate legacy IOCTL-based interface for quote generation

[Nikolay Borisov <nik.borisov@suse.com>]

On 31.01.24 г. 21:50 ч., Dan Williams wrote:
> Kuppuswamy Sathyanarayanan wrote:
>> + Dan Middleton
>>
>> Hi Boris,
>>
>> On 1/24/24 1:38 AM, Nikolay Borisov wrote:
>>> IOCTL based interface was the natural choice for interacting with the
>>> quote generation machine at a time when there wasn't anything better.
>>> Fortunately, now we have a vendor-agnostic, configfs-based one which
>>> obviates the need to have the IOCTL-based interface.
>>>
>>> Gate the relevant code behind a Kconfig option, clearly marking it as
>>> deprecated as well as introduce a runtime warning.
>>>
>>> Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
>>> ---
>>
>> In the following thread, Dan Middleton raised a point about this interface
>> being used for local attestation use cases.
>>
>> https://lore.kernel.org/all/ZbAaKAh-230Hj4BF@redhat.com/T/#m691dae9a7833a35552cafb597c838df9c2ed5f3a
>>
>> Currently, the configfs-based ABI does not support the local attestation use cases.
> 
> What are local attestation use cases, and what happens if Linux does not
> provide a local attestation interface and standardizes on remotely
> attestable as the standard?

The local attestation use case must be expanded on by your colleague Dan 
Middleton as he was the one mentioning it:

https://lore.kernel.org/all/ZbAaKAh-230Hj4BF@redhat.com/T/#m691dae9a7833a35552cafb597c838df9c2ed5f3a

Other than this Redhat/Ubuntu said they shipped this ioctl and Google as 
one of the major CSP's said they are using the config-tsm interface. 
Jeremi from Azure said that this particular ioctl interface is not 
accessible to guests - 
https://lore.kernel.org/all/ZbAaKAh-230Hj4BF@redhat.com/T/#m46070ba40150234d30dbc7cefc89a2ccb53b59e4 



So it might as well be a dead-end.