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Re: [Xen-devel] [PATCH] fxsave/fxrstor adjustments

To: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] fxsave/fxrstor adjustments
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Mon, 24 Apr 2006 17:14:18 +0100
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On 24 Apr 2006, at 16:31, Jan Beulich wrote:

This patch addresses CVE-2006-1056 (information leak from fxsave/fxrstor on AMD CPUs) and also adjusts 64-bit handling so that full 64-bit RIP/RDP values get saved/restored. More fine-grained handling may be needed if 32-bit processes are expected to properly see their selectors (native Linux doesn't currently do that either, but there is a patch to adjust
it there).

Why does this patch (and the one in Linux use 'emms' in the fxsave path rather than 'ffree st(7)' which is what AMD recommends in their published advisory? Is the former faster?

 -- Keir

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