Xiaoyao Li <xiaoyao.li@xxxxxxxxx> writes:
> On 2/29/2024 4:40 PM, Markus Armbruster wrote:
>> Xiaoyao Li <xiaoyao.li@xxxxxxxxx> writes:
>>
>>> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>>>
>>> Add property "quote-generation-socket" to tdx-guest, which is a property
>>> of type SocketAddress to specify Quote Generation Service(QGS).
>>>
>>> On request of GetQuote, it connects to the QGS socket, read request
>>> data from shared guest memory, send the request data to the QGS,
>>> and store the response into shared guest memory, at last notify
>>> TD guest by interrupt.
>>>
>>> command line example:
>>> qemu-system-x86_64 \
>>> -object '{"qom-type":"tdx-guest","id":"tdx0","quote-generation-socket":{"type": "vsock", "cid":"1","port":"1234"}}' \
>>> -machine confidential-guest-support=tdx0
>>>
>>> Note, above example uses vsock type socket because the QGS we used
>>> implements the vsock socket. It can be other types, like UNIX socket,
>>> which depends on the implementation of QGS.
>>>
>>> To avoid no response from QGS server, setup a timer for the transaction.
>>> If timeout, make it an error and interrupt guest. Define the threshold of
>>> time to 30s at present, maybe change to other value if not appropriate.
>>>
>>> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>>> Codeveloped-by: Chenyi Qiang <chenyi.qiang@xxxxxxxxx>
>>> Signed-off-by: Chenyi Qiang <chenyi.qiang@xxxxxxxxx>
>>> Codeveloped-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
>>> Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
>>
>> [...]
>>
>>> diff --git a/qapi/qom.json b/qapi/qom.json
>>> index cac875349a3a..7b26b0a0d3aa 100644
>>> --- a/qapi/qom.json
>>> +++ b/qapi/qom.json
>>> @@ -917,13 +917,19 @@
>>> # (base64 encoded SHA384 digest). (A default value 0 of SHA384 is
>>> # used when absent).
>>> #
>>> +# @quote-generation-socket: socket address for Quote Generation
>>> +# Service (QGS). QGS is a daemon running on the host. User in
>>> +# TD guest cannot get TD quoting for attestation if QGS is not
>>> +# provided. So admin should always provide it.
>>
>> This makes me wonder why it's optional. Can you describe a use case for
>> *not* specifying @quote-generation-socket?
>
> Maybe at last when all the TDX support lands on all the components, attestation will become a must for a TD guest to be usable.
>
> However, at least for today, booting and running a TD guest don't require attestation. So not provide it, doesn't affect anything excepting cannot get a Quote.
Maybe
# @quote-generation-socket: Socket address for Quote Generation
# Service (QGS). QGS is a daemon running on the host. Without
# it, the guest will not be able to get a TD quote for
# attestation.
[...]
