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Re: [Xen-devel] [PATCH] vmx: last branch recording MSR emulation

To: Jan Beulich <jbeulich@xxxxxxxxxx>, Xin B Li <xin.b.li@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] vmx: last branch recording MSR emulation
From: Keir Fraser <keir@xxxxxxxxxxxxx>
Date: Thu, 09 Aug 2007 13:49:42 +0100
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On 9/8/07 13:47, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:

> Finally, with LBR registers being used in Xen itself (optionally), you'd
> expose
> hypervisor internal information to HVM's, which is generally considered a
> security risk.

Well, that's due to the current rather stupid policy of defaulting HVM MSR
reads to read the native MSR. MSR handling needs unifying and a big clean
up, just like has now happened to the control registers. Same for CPUID
(which has a similarly stupid policy to that of MSR reads).

 -- Keir

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