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

Anthony Liguori anthony at codemonkey.ws
Thu Dec 15 14:58:55 UTC 2011

On 12/15/2011 08:54 AM, Jiri Denemark wrote:
> Hi,
> Recently I realized that all modern CPU models defined in
> /etc/qemu/target-x86_64.conf are useless when qemu is used through libvirt.
> That's because we start qemu with -nodefconfig which results in qemu ignoring
> that file with CPU model definitions. We have a very good reason for using
> -nodefconfig because we need to control the ABI presented to a guest OS and we
> don't want any configuration file that can contain lots of things including
> device definitions to be read by qemu. However, we would really like the new
> CPU models to be understood by qemu even if used through libvirt. What would
> be the best way to solve this?

Pass '-readconfig /etc/qemu/target-x86_64.conf' to pick up those models and if 
you are absolutely insistent on not giving the user any ability to change things 
on their own, cp the file from qemu.git into libvirt.git and install it in a 
safe place.


Anthony Liguori

> I suspect this could have been already discussed in the past but obviously a
> workable solution was either not found or just not implemented.
> Jirka

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