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

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Feb 19, 2024 at 01:50:12PM +0100, Markus Armbruster wrote:
> Xiaoyao Li <xiaoyao.li@intel.com> writes:
> 
> > From: Isaku Yamahata <isaku.yamahata@intel.com>
> >
> > 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@intel.com>
> > Codeveloped-by: Chenyi Qiang <chenyi.qiang@intel.com>
> > Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
> > Codeveloped-by: Xiaoyao Li <xiaoyao.li@intel.com>
> > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> > ---
> > Changes in v4:
> > - merge next patch "i386/tdx: setup a timer for the qio channel";
> >
> > Changes in v3:
> > - rename property "quote-generation-service" to "quote-generation-socket";
> > - change the type of "quote-generation-socket" from str to
> >   SocketAddress;
> > - squash next patch into this one;
> > ---
> >  qapi/qom.json                         |   6 +-
> >  target/i386/kvm/meson.build           |   2 +-
> >  target/i386/kvm/tdx-quote-generator.c | 170 ++++++++++++++++++++
> >  target/i386/kvm/tdx-quote-generator.h |  95 +++++++++++
> >  target/i386/kvm/tdx.c                 | 216 ++++++++++++++++++++++++++
> >  target/i386/kvm/tdx.h                 |   6 +
> >  6 files changed, 493 insertions(+), 2 deletions(-)
> >  create mode 100644 target/i386/kvm/tdx-quote-generator.c
> >  create mode 100644 target/i386/kvm/tdx-quote-generator.h
> >
> > diff --git a/qapi/qom.json b/qapi/qom.json
> > index 15445f9e41fc..c60fb5710961 100644
> > --- a/qapi/qom.json
> > +++ b/qapi/qom.json
> > @@ -914,13 +914,17 @@
> >  #     e.g., specific to the workload rather than the run-time or OS.
> >  #     base64 encoded SHA384 digest.
> >  #
> > +# @quote-generation-socket: socket address for Quote Generation
> > +#     Service(QGS)
> 
> Space between "Service" and "(QGS)", please.
> 
> The description feels too terse.  What is the "Quote Generation
> Service", and why should I care?

The "Quote Generation Service" is a daemon running on the host.
The reference implementation is at

  https://github.com/intel/SGXDataCenterAttestationPrimitives/tree/master/QuoteGeneration/quote_wrapper/qgs

If you don't provide this, then quests won't bet able to generate
quotes needed for attestation. So although this is technically
optional, in practice for a sane deployment, an admin should always
provide this

> 
> > +#
> >  # Since: 9.0
> >  ##
> >  { 'struct': 'TdxGuestProperties',
> >    'data': { '*sept-ve-disable': 'bool',
> >              '*mrconfigid': 'str',
> >              '*mrowner': 'str',
> > -            '*mrownerconfig': 'str' } }
> > +            '*mrownerconfig': 'str',
> > +            '*quote-generation-socket': 'SocketAddress' } }
> >  
> >  ##
> >  # @ThreadContextProperties:
> 
> [...]
> 

With regards,
Daniel
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