Re: [PATCH 4/4] x86, gart: Make sure GART does not map physmem above1TB

From: H. Peter Anvin
Date: Mon Apr 18 2011 - 11:53:44 EST


On 04/18/2011 07:52 AM, Roedel, Joerg wrote:
>>
>> Where does this limit come from?
>
> From the hardware. A GART PTE is only 32 bits in size so that it cannot
> be expanded. The physical address bits 32-39 are mapped 11:4 in the PTE.
> This can not be architecturally expanded to more than 40 physical bits.
>

AFAIK the GART format is implementation-specific (unless some standard
crept up when I wasn't looking -- this happens from time to time); this
file seems, despite its generic name, to be AMD K8 specific.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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