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

[Paolo Bonzini]

On 05/07/2016 12:06, Michael S. Tsirkin wrote:
> >      -m 2G,slots=16,maxmem=2T
> > 
> > On a host with a 39bit physaddress limit do you error
> > on that or not?  I think oVirt is currently doing something
> > similar to that, but I'm trying to get confirmation.
> 
> That would only be a problem since pci is allocated above
> maxmem so 64 bit pci addresses aren't accessible.
> With my proposal we can actually force firmware to avoid
> using 64 bit memory for that config.
> Will work better than today.

So you would remove completely the 64-bit _CRS in this case?

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?

Thanks,

Paolo