On Thu, Jan 15, 2026 at 11:32:48AM +0100, Gerd Hoffmann wrote:
> > > If we want to introduce a new element, perhaps it could look like
> > > this:
> > >
> > > <loader type='rom'>/usr/share/edk2/ovmf/OVMF.qemuvars.fd</loader>
> > > <varstore type='uefi-vars'>
> > > <template path='/usr/share/edk2/ovmf/OVMF_VARS.qemuvars.json'/>
> > > <source path='/path/to/guest.json'/>
> > > </varstore>
>
> > <loader type='rom'>/usr/share/edk2/ovmf/OVMF.qemuvars.fd</loader>
> > <varstore template='/usr/share/edk2/ovmf/OVMF_VARS.qemuvars.json'
> > path='/path/to/guest.json'/>
>
> <varstore template='...'>/path/to/guest.json</varstore> ?
>
> Following what we are doing for nvram ...
That would rule out extending with sub-elements later:
<varstore template='...'>
/path/to/guest.json
<db>...</db>
</varstore>
is not valid XML.
> That said I have no idea what guidance is typically used by libvirt when
> adding stuff to the schema, specifically the choice between attributes
> and sub-elements looks a bit random to me ...
There's no hard and fast rule so often it's down to the taste of
whoever introduces the new element/attribute. Having to go through
review normalizes this to some extent, but ultimately what we have
today is just the result of a schema growing organically over 20
years while maintaining full backwards compatibility :)
--
Andrea Bolognani / Red Hat / Virtualization
