Re: [libvirt] [Qemu-devel] libvirt<->QEMU interfaces for CPU models

On Fri, Mar 01, 2013 at 07:31:46PM +0100, Andreas Färber wrote: > Am 01.03.2013 14:12, schrieb Jiri Denemark: > > On Thu, Feb 21, 2013 at 11:58:18 -0300, Eduardo Habkost wrote: > >> = Listing CPU models = > >> > >> Requirement: libvirt needs to know which CPU models are available to be used > >> with the "-cpu" option. > >> > >> Current problem: libvirt relies on help output parsing for that. > > query-cpu-definitions is the QMP command to retrieve values compatible > with -cpu. > > And if libvirt is not using it, I really don't understand why the work > of maintaining this crappy interface has been pushed onto us in the > first place? There is no reuse between -cpu ? and QMP implementations so > it's just extra work, there is no communicated or implemented way to > extend the arch_query_cpu_definitions() implementation to become more > usable for command line output implementation (e.g., associating a PVR > value with the model name for ppc) and, while we're at it, it uses > global functions plus a stub rather than a CPUState hook with a no-op > default implementation in qom/cpu.c... I have the same questions you have. :-) But my main complaint about query-cpu-definitions is not about the implementation: it's that the interface was introduced without taking into account the requirements of libvirt regarding CPU features. It was found to be not appropriate for what libvirt needs[1], but somehow it got applied anyway.