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To: Stephan Uphoff <ups@tree.com>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Sat, 21 May 2005 22:44:25 EDT."
	<1116729865.1917.92.camel@palm> 
Date: Sun, 22 May 2005 10:31:59 +0200
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Cc: Colin Percival <cperciva@freebsd.org>,
	"freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org>
Subject: Re: Scheduler fixes for hyperthreading 
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In message <1116729865.1917.92.camel@palm>, Stephan Uphoff writes:

>Would it be enough to disable access to RDTSC for user processes?
>I believe the attack needs a very exact time source.

You'd be surprised how much software breaks if you do that :-(

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.