[Qemu-devel] Re: [kvm-devel] expose host CPU features to guests

[Avi Kivity]

Anthony Liguori wrote:
> On Wed, 2007-09-05 at 20:45 +0300, address@hidden wrote:
>   
> > Hi,
> >
> > It's a pity not to use a host CPU feature if it is available. This patch
> > exposes host CPU features to guests. It allows fine-tuning the presented
> > features from the command-line.
> >
> > The code could use some serious clean ups, but I think it is interesting
> > enough right now. I'd be happy to hear your opinion and suggestions. 
> > The diff are done against qemu cvs. I tried it with kvm, but I thinkg it
> > should be useful also for kqemu.
> >     
>
> I like this idea but I have some suggestions about the general approach.
> I think instead of defining another machine type, it would be better to
> just have a command line option like -cpuid that took a comma separate
> string of features with "all" meaning all features that the host has.
>
>   

I think qemu-cvs has a -cpu option for non-x86 which could be used for 
this.  Agree machine types are the wrong approach.


> I also think it would be nicer to use cpuid() directly instead of
> attempting to parse /proc/cpuinfo.
>   

Yes.

--
Any sufficiently difficult bug is indistinguishable from a feature.