[Libosinfo] [osinfo-db PATCH] RFC: schema: Add support to Guest Features

[Fabiano Fidêncio]

On Tue, Nov 20, 2018 at 12:11 PM Daniel P. Berrangé <berrange at redhat.com> wrote:
>
> On Thu, Nov 15, 2018 at 12:04:33PM +0100, Fabiano Fidêncio wrote:
> > One of the requests that came from KubeVirt is that would be really nice
> > if we could expose Guest supported features.
> >
> > In order to do so, I came up with this *prototype* and I'd like to ask
> > for some review of the schema before I actually start implementing
> > something on libosinfo side.
> >
> > One example of how it'll look like is:
> > <os>
> >   <features>
> >     <feature removed="true">device-hotplug</feature>
> >     <feature>cpu-hotplug</feature>
> >     <feature>NUMA</feature>
> >   </features>
> > </os>
>
> In general our documentation for the osinfo schema is poor to
> non-existant.  If we start adding features like this, however,
> I think it is important that we explicitly document what each
> one means as clearly as possible.
>
> eg 'device-hotplug' presumably refers to PCI device hotplug,
> but we should be clear it just means the OS is capable of
> supporting it. It doesn't mean its actually guaranteed to
> work. eg if either QEMU or kernel is booted with "noapci"
> it won't work.
>
> I'd be ok with the documentation simply comprising XML comments
> in the RNG schema

There's one thing (from Martin's series*) that makes me wonder whether
we should also have something else than just a <feature>foo</feature>
attribute.
His example is:
+  <features>
+    <hugepages size="1" unit="G"/>
+    <nic>passthrough</nic>
+    <io>native</io>
+    <disk cache="none"/>
+  </features>

At this point In wonder two things:
- What he's trying to achieve could also take advantage of my proposal?
- Shall we follow his suggested syntax?

I totally can see my proposal having, for instance:
<features>
  <feature>hugepages</feature>
  <feature>nic-passthrough</feature>
<features>

But then, specifying the size of hugepage, for instance, is not
something that I was planning to contemplate with my series. Neither
I'm convinced that I should.

So, the main question here is ... shall I go-ahead with my approach
and later on we can come up with a better naming for Martin's proposal
or shall we have an agreement about this (and maybe expanding my
proposal) right now?
*: https://www.redhat.com/archives/libosinfo/2018-November/msg00202.html

Best Regards,
-- 
Fabiano Fidêncio