Re: [PATCH 1/8] machine: allow -M name to differ from QOM type

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Sep 21, 2026 at 03:19:16PM +0100, Daniel P. Berrangé wrote:
> On Fri, Sep 18, 2026 at 08:06:32AM +0800, Yonggang Luo wrote:
> > - Add machine_class_set_name() so boards can keep a stable -M name
> >   when the QOM type is uniquified. machine_class_base_init still
> >   defaults the name to the QOM type without -machine.
> > - Document that MachineClass::name is the -M name, not the QOM type.
> > - Sort -M help by MachineClass::name so order matches the printed names
> >   when QOM types are prefixed (arm-virt-11.1-machine vs virt-11.1).
> > 
> > Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
> > ---
> >  hw/core/machine.c        |  6 ++++++
> >  include/hw/core/boards.h | 12 +++++++++++-
> >  system/vl.c              |  8 +++-----
> >  3 files changed, 20 insertions(+), 6 deletions(-)
> 
> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

When I apply this series and test libvirt, libvirt crashes because
it sees a machine name "virt-11.1" and then to introspect it, it
calls

  qom-list-properties type=virt-11.1-machine

this doesn't work as the actual type name is

  qom-list-properties type=arm-virt-11.1-machine

The problem we put ourselves in here is that 'query-machines' only
returns the machine name, and not the typename, so mgmt apps have
to infer that    typename==$machinename + "-machine".

Libvirt shouldn't crash of course and the fix for the crash it
"easy", but when fixing it, then libvirt simply won't be able to
introspect the machine, as it doesn't name the naming convention to
get the typename out.


I think we probably need to extend 'query-machines' so that it
includes a @typename field, so mgmt apps don't have to make the
bad assumptions about naming conventions for types.

With regards,
Daniel
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