Re: [PATCH 00 of 36] x86/paravirt: groundwork for 64-bit Xen support

Jeremy Fitzhardinge
2008-06-25T20:04:33Z

Andi Kleen wrote:
> Jeremy Fitzhardinge <jeremy@goop.org> writes:
>
>> This moves __PAGE_OFFSET up by 16 GDT slots, from 0xffff810000000000
>>
>
> GDT? PDP?
>

I meant PGD slots. Or PML4 in x86 terms.

>> to 0xffff880000000000. I have no general justification for this: th
>>
>
> This will significantly decrease the maximum amount of physical
> memory supported by Linux longer term.
>

A bit, but not "significantly". We'd already discussed that if the
amount of physical starts approaching 2^48 then we'd hope that the chips
will grow some more virtual bits.

J