Re: [PATCH] x86, AMD: Correct F15h IC aliasing issue

["H. Peter Anvin" <hpa@zytor.com>]

On 07/26/2011 11:13 AM, Borislav Petkov wrote:
> Hi Avi,
> 
> On Tue, Jul 26, 2011 at 01:59:04PM -0400, Avi Kivity wrote:
>>> This change leaves virtual region address allocation on other families
>>> and/or vendors unaffected.
>>>
>>
>> Is it possible to derive the bit positions (and the need to mask them) 
>> from the cpuid description of the cache topology and sizes?
> 
> As far as I understand your question, there's no need for deriving the
> bit positions because they're not special. You just have to have bits
> [14:12] the same across all processes - we simply opted for clearing
> them in order to keep the patch as simple as possible. But we could just
> as well hashed the library name and generated the bits from it and thus
> keep them same per library (we have that version too, btw. :)).
> 
> FWIW, in both cases, the patch should fix even the virtualization
> scenario with and without KSM.
> 
> Does that answer your question?
> 

I think the question was the width (and position) for the mask... i.e.
your [14:12] above which *is* magic.

	-hpa


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