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Re: [Xen-devel] [PATCH 10/14] Nested Virtualization: svm specific implem

To: Christoph Egger <Christoph.Egger@xxxxxxx>
Subject: Re: [Xen-devel] [PATCH 10/14] Nested Virtualization: svm specific implementation
From: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Date: Tue, 17 Aug 2010 17:57:55 +0100
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At 16:49 +0100 on 17 Aug (1282063795), Christoph Egger wrote:
> > Can you explain why we shouldn't sync the vTPR and the vlapic state when
> > the guest is in nested mode?
> When the vcpu is in guest mode then v->arch.hvm_svm.vmcb->vintr.fields.tpr
> represents the tpr of the l2 guest. The l2 guest is not allowed to touch the
> l1 guest's vTPR.

Hmmm.  I'm not sure I understand exactly what the hardware vTPR should
contain when the L2 is running; I'll have to think back about exactly
what the sync of vtpr <-> vlapic means and whether the L2 guest can
cause surprising things to happen by setting the vTPR.


Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

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