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From: "H. Peter Anvin" <hpa@zytor.com>
To: Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
	Borislav Petkov <bp@alien8.de>, Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: BUG: early intel microcode update violating alignment rules
Date: Mon, 11 Aug 2014 11:48:25 -0700	[thread overview]
Message-ID: <06991931-9f04-49fc-9ef7-ba23384aeb32@email.android.com> (raw)
In-Reply-To: <1407781112.3399765.151527845.7EC32D9C@webmail.messagingengine.com>

I don't think so.  I wouldn't count on that in the long run.

I'm having some discussions about this integrally at the moment.

On August 11, 2014 11:18:32 AM PDT, Henrique de Moraes Holschuh <hmh@hmh.eng.br> wrote:
>On Mon, Aug 11, 2014, at 11:51, H. Peter Anvin wrote:
>> We could put a buffer in the initdata region (we really could use an
>> initbss region!) or in the brk.
>
>That sounds much better than the hideous crap I came up with.  The
>buffer would need to be at least 64KiB in size to be on the safe side. 
>The largest public microcode update ATM is 23KiB.
>
>I am not sure if we might need more than 64KiB: the Intel SDM mentions
>that in real mode the update data must not cross a segment boundary,
>and
>also must not exceed a segment limit.  I am a bit rusty on real mode,
>but doesn't that mean, in practice, that microcode update data size is
>limited in size to 64KiB?

-- 
Sent from my mobile phone.  Please pardon brevity and lack of formatting.

  reply	other threads:[~2014-08-11 18:48 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-09 23:19 Henrique de Moraes Holschuh
2014-08-11 10:22 ` Borislav Petkov
2014-08-11 13:16   ` Henrique de Moraes Holschuh
2014-08-11 14:00     ` Borislav Petkov
2014-08-11 14:50       ` H. Peter Anvin
2014-08-11 18:52       ` Bill Davidsen
2014-08-11 19:15         ` Borislav Petkov
2014-08-14 13:12         ` Henrique de Moraes Holschuh
2014-08-11 14:51 ` H. Peter Anvin
2014-08-11 18:18   ` Henrique de Moraes Holschuh
2014-08-11 18:48     ` H. Peter Anvin [this message]
2014-08-31 19:45 ` early microcode: how to disable at runtime? Henrique de Moraes Holschuh
2014-08-31 19:48   ` H. Peter Anvin
2014-08-31 20:11     ` Henrique de Moraes Holschuh
2014-09-01  5:13       ` Borislav Petkov
2014-09-01 10:19         ` Henrique de Moraes Holschuh
2014-09-01 16:35         ` H. Peter Anvin
2014-09-01 17:43           ` Henrique de Moraes Holschuh
2014-09-01 18:48             ` H. Peter Anvin
2014-09-01 19:59               ` Henrique de Moraes Holschuh
2014-09-02  6:33                 ` Borislav Petkov
2014-09-02 13:16                   ` Henrique de Moraes Holschuh
2014-09-03  6:40                     ` Borislav Petkov
2014-09-03 12:43                       ` Henrique de Moraes Holschuh
2014-09-04 15:42                         ` Borislav Petkov
2014-09-04 17:45                           ` Henrique de Moraes Holschuh
2014-09-05  8:50                             ` Borislav Petkov
2014-09-05 14:23                               ` Henrique de Moraes Holschuh
2014-09-04 18:37                           ` Yu, Fenghua
2014-09-05  8:52                             ` Borislav Petkov

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