Re: [Xen-devel] [PATCH 3/5] svm: implement instruction fetch par

To:	Andre Przywara <andre.przywara@xxxxxxx>
Subject:	Re: [Xen-devel] [PATCH 3/5] svm: implement instruction fetch part of DecodeAssist
From:	Keir Fraser <keir@xxxxxxx>
Date:	Mon, 18 Apr 2011 13:37:21 +0100
Cc:	xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date:	Mon, 18 Apr 2011 05:38:31 -0700
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On 15/04/2011 13:22, "Andre Przywara" <andre.przywara@xxxxxxx> wrote:

> Newer SVM implementations (Bulldozer) copy up to 15 bytes from the
> instruction stream into the VMCB when a #PF or #NPF exception is
> intercepted. This patch makes use of this information if available.
> This saves us from a) traversing the guest's page tables, b) mapping
> the guest's memory and c) copy the instructions from there into the
> hypervisor's address space.
> This speeds up #NPF intercepts quite a lot and avoids cache and TLB
> trashing.

Rewritten quite a bit and applied as c/s 23238. You probably should check it
still works and with the performance improvement you expect. :-)

 -- Keir

> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> 
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Re: [Xen-devel] [PATCH 3/5] svm: implement instruction fetch part of Dec