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Re: [Xen-devel] A question about guest_walk_tables

from [Tim Deegan]

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To:	"Tian, Kevin" <kevin.tian@xxxxxxxxx>
Subject:	Re: [Xen-devel] A question about guest_walk_tables
From:	Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Date:	Wed, 5 Dec 2007 10:34:44 +0000
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At 18:22 +0800 on 05 Dec (1196878922), Tian, Kevin wrote:
> Hi, Tim,
>       Just a curious question. Any reason why sh_page_fault can't
> benefit vtlb_lookup to skip heavy-weight guest_walk_tables, like other
> places like sh_gva_to_gfn?

For cases when we go on to make the shadow pagetables, we need the full
walk available so we know which MFNs to shadow.

I don't know whether it would be worth adding a vtlb lookup for the
real-fault case; the fast-path code for not-present and MMIO catches a
lot of genuine faults already.  We should definitely add the walk result
to the vTLB in any case.

Thanks,

Tim.

-- 
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Citrix Systems.
[Company #5334508: XenSource UK Ltd, reg'd c/o EC2Y 5EB, UK.]

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