Re: [PATCH v4 50/66] i386/tdx: handle TDG.VP.VMCALL<GetQuote>

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+ Feng Qiu,

On 2/23/2024 12:30 AM, Daniel P. Berrangé wrote:
On Wed, Jan 24, 2024 at 10:23:12PM -0500, Xiaoyao Li wrote:
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.

Can you confirm again exactly what QGS impl you are testing against ?
> I've tried the impl at

which supports UNIX sockets and VSOCK. In both cases, however, it
appears to be speaking a different protocol than your QEMU impl
below uses.

Specifically here:

it is reading 4 bytes of header, which are interpreted as the length
of the payload which will then be read off the wire. IIUC the payload
it expects is the TDREPORT struct.

Your QEMU patches here meanwhile are just sending the payload from
the GetQuote hypercall which is the TDREPORT struct.

IOW, QEMU is not sending the 4 byte length header the QGS expects.
and whole thing fails.

I'm using the one provided by internal folks, which supports interpreting the payload without the header.

I don't know when will the updated implementation show up in public github. @Feng Liu can help on it.

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 <>
Signed-off-by: Xiaoyao Li <>

With regards,

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