[libvirt] Interim fix for exposing VMware firmware=bios|efi in libvirt XML

[Richard W.M. Jones]

https://bugzilla.redhat.com/show_bug.cgi?id=1217444

VMware guests can use either BIOS or UEFI firmware.  VMware itself
exposes this information in the VMX file and it's available to the ESX
driver in libvirt.  virt-v2v wants to consume this information.

Unfortunately after a few years and iterations we've not come up with
an acceptable patch to expose “has UEFI” in the libvirt XML.  (Latest
patch was:
https://www.redhat.com/archives/libvir-list/2016-October/msg00045.html )

Could we instead add a temporary addition to the XML generated by the
ESX driver?  I'm thinking something like the existing <vmware:moref>
and <vmware:datacenterpath> fields:

<domain type='vmware' xmlns:vmware='http://libvirt.org/schemas/domain/vmware/1.0'>
  <name>Fedora</name>
...
  <vmware:datacenterpath>ha-datacenter</vmware:datacenterpath>
  <vmware:moref>2</vmware:moref>
  <vmware:firmware>uefi</vmware:firmware>  <!-- "bios" or "uefi" -->
</domain>

This field would be informational, ie. the ESX driver would create it
but not read it when creating new VMs.

This would solve our immediate problem in virt-v2v and is pretty
simple to implement.  Also it doesn't close off any future general
solution.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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