Re: [Xen-devel] Page tables in Xen

[Tim Deegan <Tim.Deegan@xxxxxxxxxx>]

At 20:47 +0800 on 05 Dec (1196887651), tgh wrote:
> hi
> in the PV mode, when VM is migrated, the shadow page table will be 
> created , that is ,the every active process pagetable in the guestOS 
> will have a copy in the VMM, while the original one is maintianed as 
> virtual-to-physical address mapping , is it right?

Yes, though as I said we only shadow pagetables on demand when they are used.

> then, when the 
> guestOS process is scheduled , the shadow page table will be set into 
> the CR3 and the CPU address mapping will be worked with the shadow 
> pagetable rather than the original one, is it right?

Yes.

> while every update 
> to the process original pagetable in the guestOS will be trap into the 
> VMM , where the shadow pagetable is updated and coherented with the 
> original one, is it right?

Yes.

Why are you asking this, by the way?  Are you trying to write code, 
or debug a problem, or write documentation?  

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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