Re: [Qemu-devel] [PATCH 0/2] target-i386: "custom" CPU model + script to dump existing CPU models

[Michael S. Tsirkin]

On Wed, Jun 24, 2015 at 11:18:18AM -0300, Eduardo Habkost wrote:
> On Tue, Jun 23, 2015 at 11:28:06PM +0200, Michael S. Tsirkin wrote:
> > On Tue, Jun 23, 2015 at 02:42:37PM -0300, Eduardo Habkost wrote:
> > > On Tue, Jun 23, 2015 at 07:29:15PM +0200, Andreas Färber wrote:
> > > > In summary you seem to be saying that all the years we have spent
> > > > fiddling around with those mind-boggling compat_props in QEMU were in
> > > > vain because libvirt now wants to start their own versioning system to
> > > > give users more degrees of freedom even when you can't articulate a
> > > > single concrete reason why users may want to do so.
> > > 
> > > I had a similar reaction when I learned about this libvirt
> > > expectation/requirement I was never aware of. But "we spent lots of
> > > effort trying to do things differently" doesn't seem like a valid
> > > justification for design decision.
> > 
> > "Users will be hurt because they'll run untested configurations"
> > seems like a valid reason.
> 
> I trust libvirt developers to test their CPU definitions as carefully as
> we test ours.

Maybe someone can do a write-up explaining how do requirements
and needs differ?

So far, it looks like gratituos code duplication based on a
mis-understanding, or highly unlikely theoretical what-if scenarious.

Basing our stable interfaces on such grounds might not be a good idea.


> -- 
> Eduardo