Re: [PATCH] hvmloader: write extra memory in CMOS

Jan Beulich
Tue, 12 Nov 2013 14:13:26 -0000

>>> On 12.11.13 at 15:00, Wei Liu <wei.liu2@citrix.com> wrote:
> On Tue, Nov 12, 2013 at 01:56:02PM +0000, Jan Beulich wrote:
>> >>> On 12.11.13 at 14:39, Wei Liu <wei.liu2@citrix.com>
wrote:
>> > On Tue, Nov 12, 2013 at 01:21:36PM +0000, Jan Beulich wrote:
>> >> >>> On 12.11.13 at 13:37, Wei Liu
<wei.liu2@citrix.com> wrote:
>> >> > However in some CMOS maps I found those bytes are marked
as reserved.
>> >>
>> >> Exactly. The question is whether some _other_ BIOSes then use
>> >> these register for other purposes...
>> >>
>> >
>> > So I think now the solution is to make this code OVMF only, are
you fine
>> > with this?
>>
>> Yes, provided you widen the location to at least 4 bytes.
>>
>
> I''m afraid I cannot widen the location (not for technical reason).
It''s
> a conventional protocol used by these non traditional BIOSes. It
doesn''t
> make sense to change Xen only, right?

Maybe, maybe not. But those other BIOSes must have some
understanding of how to support >1Tb systems?

Jan