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

On Mon, Mar 26, 2012 at 01:59:05PM +0200, Avi Kivity wrote: > On 03/26/2012 01:24 PM, Jiri Denemark wrote: > > ... > > > > The command line becomes unstable if you use -nodefconfig. > > > > > > -no-user-config solves this but I fully expect libvirt would continue to use > > > -nodefconfig. > > > > Libvirt uses -nodefaults -nodefconfig because it wants to fully control how > > the virtual machine will look like (mainly in terms of devices). In other > > words, we don't want any devices to just magically appear without libvirt > > knowing about them. -nodefaults gets rid of default devices that are built > > directly in qemu. Since users can set any devices or command line options > > (such as enable-kvm) into qemu configuration files in @SYSCONFDIR@, we need to > > avoid reading those files as well. Hence we use -nodefconfig. However, we > > would still like qemu to read CPU definitions, machine types, etc. once they > > become externally loaded configuration (or however we decide to call it). That > > said, when CPU definitions are moved into @DATADIR@, and -no-user-config is > > introduced, I don't see any reason for libvirt to keep using -nodefconfig.

> > > > I actually like > > -no-user-config > > more than > > -nodefconfig -readconfig @DATADIR@/... > > since it would avoid additional magic to detect what files libvirt should > > explicitly pass to -readconfig but basically any approach that would allow us > > to do read files only from @DATADIR@ is much better than what we have with > > -nodefconfig now. > > That's how I see it as well. > +1 except that instead of -no-user-config we can do what most other programs do. If config file is specified during invocation default one is not used. After implementing -no-user-config (or similar) we can drop -nodefconfig entirely since its only user will be gone it its semantics is not clear.