[libvirt] [PATCH v3 1/9] qemu: provide support to query the SEV capability

[Andrea Bolognani]

On Tue, 2018-03-27 at 09:26 -0500, Brijesh Singh wrote:
> > You're going to have to either fetch capabilities from your own
> > QEMU 2.12 binary or hack it up by adding the return data in the
> > right spot and call tests/qemucapsfixreplies to re-align the ids.
> 
> Right, running the tests/qemucapsprobe on my system I see that 
> query-sev-capabilities command returns a valid data. In my local branch, 
> I updated the caps_2.12.0.x86_64.replies with response. With those 
> changes I no longer get the internal error but 
> tests/qemucapabilitiestest still fails for me with below error message:
> 
> 29) caps_2.12.0(x86_64)                                               ...
>   In 
> '/home/amd/workdir/upstream/libvirt/tests/qemucapabilitiesdata/caps_2.12.0.x86_64.xml':
>   Offset 7143
>   Expect [060]
>   Actual [306]
> 
> It is basically pointing to microcode version change, do I need to 
> update the cap with new version ?

After you've tweaked the .replies file, you can just run

  $ VIR_TEST_REGENERATE_OUTPUT=1 make check

and the .xml file will be refreshed, microcode version and all.

> > I think you can get away with the latter, as we're going to want
> > to refresh the replies files once 2.12 is released anyway.
> 
> I am not able to follow this comment, let me explain the situation.
> The QEMU_CAPS_SEV flag was set to indicate QEMU supports the 
> 'query-sev-capabilities' QMP command and sev-guest object. That merely 
> indicates that command exist but does not means that command will always 
> execute successfully. e.g If hypervisor does not support the SEV feature 
> then query-sev-capabilities will return error. That means if 
> tests/qemucapsprobe is used to generate the replies on non-SEV capable 
> system then .replies will not contain output of query-sev-capabilities 
> command. Will this be an issue ?

Not at all. That's already the case for a lot of features.

My comment was merely pointing out that the capabilities data we
have in the tree right now is for QEMU 2.12.0-rc0, and once QEMU
2.12 is officially released we will want to collect it again.
It's not something you need to worry about, really :)

-- 
Andrea Bolognani / Red Hat / Virtualization