Re: [Xen-devel] Re: [GIT PULL] xen /proc/mtrr implementation

From: H. Peter Anvin
Date: Mon May 25 2009 - 12:06:28 EST


Andi Kleen wrote:
>
> To my knowledge the only CPUs with broken PAT are some very old Pentium
> Pros dating from back the time when PAT was new and noone used it.
> On those it should be disabled or the high bits not used.
>
> The kernel is overall too conservative with its white list.
>
> Today a lot of other common operating systems use PAT extensively,
> so in general it works on the hardware level.
>

Well, we don't use the high bits exactly for this reason.

-hpa

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

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