Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Dec 21, 2009 at 12:22:53PM +0100, Alexander Graf wrote:
> 
> On 21.12.2009, at 12:18, Michael S. Tsirkin wrote:
> 
> > On Mon, Dec 21, 2009 at 01:12:26PM +0200, Avi Kivity wrote:
> >> On 12/20/2009 07:18 PM, Michael S. Tsirkin wrote:
> >>> 
> >>>>> Hmm, then, shouldn't either kvm or qemu mask features that we do not
> >>>>> emulate well enough to make windows not crash?
> >>>>> 
> >>>> -cpu host does that already, no?
> >>>> 
> >>>> Alex
> >>>> 
> >>> I expected so, but Avi here seems to say windows will crash if you
> >>> use a new CPU with it ...
> >>> 
> >> 
> >> No, Windows tries to detect changes in your hardware and assumes that if  
> >> too many things change, you might be a pirate and requires you to phone  
> >> their offices to re-authenticate.
> > 
> > How often does a casual user upgrade his host CPU?
> 
> I tend to have my VM images on an NFS share and expect them to work properly on all PCs I work on.
> So I guess the answer is "often"?
> 
> Alex

Yes but you are not a casual user, are you?  Consider a 64 bit guest to
see why moving a VM across machines needs some planning.

-- 
MST