Re: [Qemu-devel] [libvirt] Modern CPU models cannot be used with libvirt

[Anthony Liguori]

On 03/25/2012 10:18 AM, Avi Kivity wrote:
> On 03/25/2012 05:07 PM, Anthony Liguori wrote:
> > > As log as qemu -nodefconfig -cpu westmere -M pc1.1
> >
> >
> > -nodefconfig is going to eventually mean that -cpu westmere and -M
> > pc-1.1 will not work.
> >
> > This is where QEMU is going.  There is no reason that a normal user
> > should ever use -nodefconfig.
>
> I don't think anyone or anything can use it, since it's meaning is not
> well defined.  "not read any configuration files" where parts of qemu
> are continually moved out to configuration files means its a moving target.

I think you assume that all QEMU users care about forward and backwards 
compatibility on the command line about all else.

That's really not true.  The libvirt folks have stated repeatedly that command 
line backwards compatibility is not critical to them.  They are happy to require 
that a new version of QEMU requires a new version of libvirt.

I'm not saying that backwards compat isn't important--it is.  But there are 
users who are happy to live on the bleeding edge.

> Suppose we define the southbridge via a configuration file.  Does that
> mean we don't load it any more?

Yes.  If I want the leanest and meanest version of QEMU that will start in the 
smallest number of milliseconds, then being able to tell QEMU not to load 
configuration files and create a very specific machine is a Good Thing.  Why 
exclude users from being able to do this?

Regards,

Anthony Liguori

>