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Re: [Xen-devel] (v2) Design proposal for RMRR fix

>>> On 14.01.15 at 13:29, <george.dunlap@xxxxxxxxxxxxx> wrote:
> On 01/14/2015 08:06 AM, Tian, Kevin wrote:
>> We discussed earlier there are two reasons that some conflicts may not be 
>> avoided:
>>      - RMRRs conflicting with guest BIOS in <1MB area, as an example of 
>> hard conflicts
>>      - RMRRs conflicting with lowmem which is low enough then avoiding it
>> will either break lowmem or make lowmem too low to impact guest (just
>> an option being discussed)
> So here you're assuming that we're going to keep the lowmem / mmio hole
> / himem thing.  Is that necessary?  I was assuming that if we have
> arbitrary RMRRs, that we would just have to accept that we'd need to be
> able to punch an arbitrary number of holes in the p2m space.

On the basis that the host would have placed the RMRRs in its MMIO
hole, I think I agree with Kevin that if possible we should stick with
the simpler lowmem / mmio-hole / highmem model if possible. If we
really find this too limiting, switching to the more fine grained model
later on will still be possible.


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