Re: (v2) Design proposal for RMRR fix

[George Dunlap <george.dunlap@eu.citrix.com>]

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.

That would involve telling qemu-upstream about the existence of such
holes, but that's something I think we need to be able to do at some
point anyway.

If we're going to tell xc_hvm_build about the RMRR ranges anyway, it
might as well just go ahead and punch the holes arbitrarily, rather than
restricting itself to simply making the mmio hole larger.

 -George