Re: [RFC PATCH 05/15] virt: tdx-guest: Add TDCM helpers and TEE-IO support check

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

On 28.10.26 г. 7:42 ч., Duan, Zhenzhong wrote:
> 
> 
>> -----Original Message-----
>> From: Nikolay Borisov <nik.borisov@suse.com>
>> Subject: Re: [RFC PATCH 05/15] virt: tdx-guest: Add TDCM helpers and TEE-IO
>> support check
>>
>>
>>
>> On 26.10.26 г. 3:26 ч., Xiaoyao Li wrote:
>>> On 10/14/2026 2:11 PM, Duan, Zhenzhong wrote:
>>>>> This is used to allow TD guest TEE-IO Device Control and Management
>>>>> (TDCM) module to
>>>>> manage the device. The TDCM leaf functions are defined in the following
>>>>> table
>>>>>
>>>>> Is TDCM module implemented via the NRX facility ?  The TDX Connect spec
>>>>> never mentions the TDCM module. A bit more details are required in
>> order
>>>>> to better understand why you've implemented this the way you have.
>>>> "TDCM module" is GHCI terminology. In this series, the guest-side
>>>> implementation is in the TDX TSM driver; it is not an NRX module.
>>>
>>> I think the TDX guest TSM driver is just the implementation of the "TDCM
>> module"
>>> called in GHCI, right?
>>
>> I think we are entering a dangerous bikeshedding territory here. But
>> IIUC TDCM seems to be something which the TD calls, because it sends the
>> TDCM function ids to the host, so the TDCM should really be implemented
>> by the host. But I think such construct just adds more confusion, TDCM
>> is just a subset of the GHCI, so nothing really more special.
> 
> GHCI spec says:
> 
> "This is used to allow TD guest TEE-IO Device Control and Management (TDCM) module to
> manage the device."
> 
> So I think "TDCM module" term in GHCI spec is talking about guest side - the TDX TSM driver.
> 
> Since "TDCM module" term is confusing for reader, so I plan to drop it
> in next version, I plan to use "TDCM request" to denote the guest-side
> operations and "TDCM implementation" to denote the host-side logic.
> let me know if this distinction makes sense to you all, or if you have
> any other suggestions.

Yep, makes sense to me.