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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@suse.de>,
	virtualization@lists.osdl.org, Chris Wright <chrisw@sous-sol.org>,
	xen-devel@lists.xensource.com,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [Xen-devel] Re: [patch 17/24] Xen-paravirt_ops: avoid having a bad	selector in %gs during context switch
Date: Wed, 21 Feb 2007 15:29:37 -0800	[thread overview]
Message-ID: <45DCD5E1.5070201@goop.org> (raw)
In-Reply-To: <45DCD4D0.2000101@vmware.com>

Zachary Amsden wrote:
> I agree with that, but especially because this is not even the right
> place to save and clear gs; when userspace uses an LDT based %gs, you
> need to do this all the way back in mmu_context.h before you switch
> the LDT out. 

Yeah.  This patch was really just to shut my debug Xen build up.  
There's no correctness issue one way or the other, so it doesn't really
matter that it doesn't catch LDT-using processes.

> And I noticed this martian hanging out in mmu_context.h:
>
> #define deactivate_mm(tsk, mm)                  \
>        asm("movl %0,%%gs": :"r" (0));

Yeah, I've always wondered what this is for.  Its a remnant of a
remnant, I think.

    J

  reply	other threads:[~2007-02-21 23:29 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20070221205254.169835700@goop.org>
     [not found] ` <20070221205323.770169136@goop.org>
2007-02-21 22:10   ` Andi Kleen
2007-02-21 22:14     ` Jeremy Fitzhardinge
2007-02-21 22:16     ` Keir Fraser
2007-02-21 23:25     ` [Xen-devel] " Zachary Amsden
2007-02-21 23:29       ` Jeremy Fitzhardinge [this message]
     [not found] ` <20070221205322.869165491@goop.org>
2007-02-21 22:15   ` [patch 05/24] Xen-paravirt_ops: Add pagetable accessors to pack and unpack pagetable entries Andi Kleen
2007-02-21 22:20     ` Jeremy Fitzhardinge
2007-02-21 23:20     ` Rusty Russell
2007-02-21 23:27       ` [Xen-devel] " Jeremy Fitzhardinge
     [not found] ` <20070221205323.842917348@goop.org>
2007-02-22  3:10   ` [patch 18/24] Xen-paravirt_ops: Some generic early printk & boot console fixups Andrew Morton
2007-02-22  5:48     ` Jeremy Fitzhardinge
2007-02-22  8:33       ` Gerd Hoffmann

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