Re: [v1 1/2] xen/p2m: Create identity mappings for PFNs beyound E820 and PCI BARs

Jan Beulich
2013-10-29T08:23:42Z

>>> On 28.10.13 at 17:58, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> On Fri, Oct 25, 2013 at 04:08:19PM -0600, Bjorn Helgaas wrote:
>> If you can look at PCI host bridge apertures instead of BARs, that
>> would solve both problems. Reassigning those apertures is
>> theoretically possible but is not even a gleam in our eyes yet.
>
> <nods> I think I have to have both (BARs and host bridge apertures) as when
> we do PCI passthrough to a guest - we might do it without a bridge.

Why? Aren't the host bridge ranges necessarily a superset of the
individual devices' BARs?

Jan