Re: CCA capability qeury QMP command

[Alex Bennée]

Itaru Kitayama <itaru.kitayama@linux.dev> writes:

(+CC Markus, Eduardo, Marcel for QMP API)

> Hi,
> I’ve been looking at the libvirt code to add Arm’s CCA support for
> some time and I am wondering how QEMU folk want to implement the CCA
> query command. Any pointer would be appreciated.

Jean-Philippe's latest posting is here:

  Message-ID: <20241125195626.856992-2-jean-philippe@linaro.org>
  Date: Mon, 25 Nov 2024 19:55:59 +0000
  Subject: [PATCH v3 00/26] arm: Run Arm CCA VMs with KVM
  From: Jean-Philippe Brucker <jean-philippe@linaro.org>

In that series the following objects are created:

  static void rme_guest_class_init(ObjectClass *oc, void *data)
  {
      object_class_property_add_str(oc, "personalization-value", rme_get_rpv,
                                    rme_set_rpv);
      object_class_property_set_description(oc, "personalization-value",
              "Realm personalization value (512-bit hexadecimal number)");

      object_class_property_add_enum(oc, "measurement-algorithm",
                                     "RmeGuestMeasurementAlgorithm",
                                     &RmeGuestMeasurementAlgorithm_lookup,
                                     rme_get_measurement_algo,
                                     rme_set_measurement_algo);
      object_class_property_set_description(oc, "measurement-algorithm",
              "Realm measurement algorithm ('sha256', 'sha512')");

      object_class_property_add_bool(oc, "measurement-log",
                                     rme_get_measurement_log,
                                     rme_set_measurement_log);
      object_class_property_set_description(oc, "measurement-log",
              "Enable/disable Realm measurement log");
  }

So I guess we could probe for the personalization-value. However that
seems very arch specific.

All confidential guests (PPC PEF, s390x, CCA and x86 SEV) seem to set up
ConfidentialGuestSupport with the ->ready field to true and a
confidential-guest-support property associated with the machine. But I
don't think that is currently exposed via QMP.

I suspect from libvirt's point of view we want to have a common probing
for CCA capable accelerators before we dive into architectural specifics?

>
> Thanks,
> Itaru. 

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro