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

[Paolo Bonzini]

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

Thanks,

Paolo