Re: [Qemu-devel] [PATCH v2 0/6] x86: Physical address limit patches

[Michael S. Tsirkin]

On Tue, Jul 05, 2016 at 01:46:58PM +0200, Paolo Bonzini wrote:
> 
> 
> On 05/07/2016 13:09, Michael S. Tsirkin wrote:
> > > How do you handle migration in the above scenario from say 46bit host to
> > > 39bit host, where the firmware has mapped (while running on the source)
> > > a 64-bit BAR above the destination's maximum physical address?
> >
> > Again management would specify how much 64 bit pci space firmware should 
> > use.
> > If more is specified than host can support we can error out.
> 
> Ok, so the destination would fail to start.
> 
> It sounds good, and it may provide a good reason not to enable
> autodetection of phys-addr-bits for new machine types.  We still want
> David's patches for -cpu host,

Right, but I think current patches aren't limited to -cpu host -
I guess they will need some changes then?

> and for improved backwards compatibility
> now that KVM_SET_MSR error detection is strict.

Sounds good.


> Thanks,
> 
> Paolo