Re: [libvirt] [RFC] Support for CPUID masking
On 10/13/2009 11:40 AM, Daniel P. Berrange wrote:
On Tue, Oct 13, 2009 at 02:56:41AM -0400, john cooper wrote:
> Dor Laor wrote:
>> What about another approach for the cpuid issue:
>> I think that dealing with specific flags is pretty error prone on all
>> levels - virt-mgr, libvirt, qemu, migration, and even the guest.
>
> ..and performance verification, QA, and the average end user.
> Unless we reduce all possible combinations of knob settings
> into a few well thought out lumped models the complexity can
> be overwhelming.
That is a policy decision for applications to make. libvirt should expose
the fine grained named CPU models + arbitrary flags, and other bits of
info as appropriate (eg formal model for core/socket topology). Apps can
decide whether they want to turn that into a higher level concept where
admins pick one of a handful of common setups, or expose the full level
of control
As long as the cpu model is exposed (both host and guest) it works for
me. My guess is that most apps will try to be as dumb as possible.
Some might only use problematic flags like the NX bit that might be off
in the bios menu.
Daniel