Re: [Qemu-devel] [PATCH v2 9/9] tpm: Added support for TPM emulator

[Stefan Berger <stefanb@linux.vnet.ibm.com>]

On 04/10/2017 06:07 AM, Patrick Ohly wrote:
> On Mon, 2017-04-10 at 09:54 +0000, Marc-André Lureau wrote:
>
>> By "public protocol", I mean qemu communication with a foreign
>> project, swtpm or other.
>>
>> If qemu grows new needs, or if the protocol is found limited or buggy,
>> it may change. Subtle interactions may break between various
>> implementations.  The minimum would be some versioning or
>> capabilities. A document describing the states and messages
>> allowed/denied & effects would be quite necessary.
> Stefan, is there any documentation besides the source?

No.

>
> Just asking, I don't think it is needed because...
>
>> Otoh, there doesn't seem to be other users of this protocol, or other
>> implementations. So it may make sense to make it qemu-specific, and
>> thus "private": the protocol and implementation can evolve without
>> risk to break other users. This gives us a lot more flexibility and
>> control, and doesn't have to be very strictly documented (although it
>> is still better to be strict, but requires more effort).
> ... I suspect it falls into this camp. I can't think of any users of the
> protocol besides swtpm itself and now qemu. Stefan, is that correct?
>

Correct. Only swtpm client tools (swtpm_ioctl) and now your QEMU patches 
are using the protocol.