Re: [PATCH v1 3/4] qemu_domain.c: do not launch ppc64 guests with 'pmu' setting

On Tue, 2020-03-24 at 09:27 -0300, Daniel Henrique Barboza wrote: > Andrea, I see that the behavior of the 'panic' device in the ppc64 XML is to > always add a:

> > For the sake of completeness, I'll also mention that we can simply allow <pmu/> to be > declared in the XML, handling the <pmu state='on'/> inside the QEMU driver to not add the > bogus '.pmu' parameter for QEMU ppc64, forbid <pmu state='off'/> to be declared, and > nothing else. No auto-generation of XML indicating that the guest will support a PMU. Looking again at how other architectures, specifically x86 and ARM, handle this, the PMU is generally enabled by default without this fact being reflected in the domain XML; the user can then go ahead and specifically ask for it to be turned on or off, at which point libvirt will add the relevant bits to the QEMU command line. This is basically the second behavior you're describing above, and I think it would be perfectly fine if that's the one we would adopt for ppc64.