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Re: [Xen-devel] Re: what's the purpose of linear page table (PML4 entry

To: weiming <zephyr.zhao@xxxxxxxxx>
Subject: Re: [Xen-devel] Re: what's the purpose of linear page table (PML4 entry 258)
From: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Date: Tue, 1 Apr 2008 08:52:18 +0000
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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At 08:47 +0000 on 01 Apr (1207039678), Tim Deegan wrote:
> At 14:15 -0400 on 31 Mar (1206972951), weiming wrote:
> > I find that it give the same pte value as I manually walking the 4 level
> > page table directory.
> > So I guest it facilitates the locating of a pte from va. It removes the
> > 4-level looking up process: pgd->pud->pmd->pt->pte
> > It saves time. Am I right?
> IIRC, it just does that walk internally and hands back the answer. 

Excuse me, not enough coffee.  Yes, it uses the linear mapping of the
pagetable to save time.


Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Citrix Systems (R&D) Ltd.
[Company #02300071, SL9 0DZ, UK.]

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