Re: [Xen-devel] [RFC][PATCH 4/5] tools:firmware:hvmloader: reserve RMRR mappings in e820

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 08.08.14 at 23:47, <kevin.tian@xxxxxxxxx> wrote:
>>  From: Chen, Tiejun
>> Sent: Thursday, August 07, 2014 4:03 AM
>> 
>> We need to reserve all RMRR mappings in e820 to avoid any
>> potential guest memory conflict.
> 
> strictly speaking besides reserving in e820, you should also poke later
> MMIO BAR allocations to avoid confliction too. Currently it's relative
> to low_mem_pgend, which is likely to be different from host layout
> so it's still possible to see a virtual MMIO bar base conflicting to the
> RMRR ranges which are supposed to be sparse.

Correct. And what's worse: Possible collisions between RMRRs and
the BIOS we place into the VM need to be taken care of, which may
turn out rather tricky.

Jan


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