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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 26 Jul 2011 11:16:56 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Borislav Petkov <bp@...64.org>
CC:	Avi Kivity <avi@...hat.com>, Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>,
	"Przywara, Andre" <Andre.Przywara@....com>,
	"Pohlack, Martin" <Martin.Pohlack@....com>
Subject: Re: [PATCH] x86, AMD: Correct F15h IC aliasing issue

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.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/