linux-kernel - Re: [patch 17/24] Xen-paravirt_ops: avoid having a bad selector in %gs during context switch

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Date:	Wed, 21 Feb 2007 23:10:02 +0100
From:	Andi Kleen <ak@...e.de>
To:	virtualization@...ts.osdl.org
Cc:	Jeremy Fitzhardinge <jeremy@...p.org>,
	Chris Wright <chrisw@...s-sol.org>,
	xen-devel@...ts.xensource.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [patch 17/24] Xen-paravirt_ops: avoid having a bad selector in %gs during context switch


>  	/*
> +	 * Temporary hack: zero gs now that we've saved it so that Xen
> +	 * doesn't try to reload the old value after changing the GDT
> +	 * during the context switch.  This can go away once Xen has
> +	 * been taught to only reload %gs when it absolutely must.
> +	 */
> +	loadsegment(gs, 0);

Sorry, but i don't really want that unconditionally in the context switch.
Adding a paravirt ops for it would be also ugly. Can Xen be fixed?

-Andi
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