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Date: Fri, 04 May 2007 10:07:08 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: "Eric W. Biederman" <ebiederm@xmission.com>
CC: Jeremy Fitzhardinge <jeremy@goop.org>,
       Rusty Russell <rusty@rustcorp.com.au>, Andi Kleen <ak@suse.de>,
       Chris Wright <chrisw@sous-sol.org>, Zachary Amsden <zach@vmware.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 3/3] boot bzImages under paravirt
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Eric W. Biederman wrote:
> 
> We have real mystery historical cases in Gujin and ELILO.  So it
> probably makes sense at this point to force a gdt reload if we can and
> otherwise require all of the segments %ds, %es, %fs, %gs to be loaded
> with a valid segment, that we can reach everything we need to touch
> from.
> 

I think we should avoid using %fs and %gs (no use for them, anyway); but
 I think it's a decent expectation to have %cs, %ds, %es, and %ss set up.

Gujin seems to have a near-zero user community, so if they have to rev
their code it wouldn't be a big deal (the author keeps trying to push
some crack-smoking "Gujin native" patches into the kernel, too), but
breaking ELILO would hurt anyone using Intel Macs.

	-hpa