[libvirt] QEMU CPU model versioning/compatibility (was Re: KVM call minutes July 31th)

[Eduardo Habkost]

On Tue, Jul 31, 2012 at 04:32:05PM +0200, Juan Quintela wrote:
> - 1.2 plans for CPU model versioning/compatibility (eduardo)
>   (global properties vs QOM vs qdev)
>   how to do it ?  configuration file?  moving back to the code?
>   different external interface from internal one

(CCing libvir-list)

So, the problem is (please correct me if I am wrong):

- libvirt expects the CPU models from the current config file to be
  provided by QEMU. libvirt won't write a cpudef config file.
- Fixing compatibility problems on the CPU models (even the ones that
  are in config files) are expected to be QEMU's responsibility.

Moving the CPU models inside the code is a step backwards, IMO. I don't
think loading some kind of data from an external file (provided and
maintained by QEMU itself) should be considered something special and
magic, and make the data there a second-class citizen (that QEMU refuses
to give proper support and keep compatibility).

But if it will make us stop running in circles every time something
related to those files needs to be changed (remember the -no-user-config
discussion?), I think I will accept that.

-- 
Eduardo