Re: [Xen-devel] Page tables in Xen

[tgh <wwwwww4187@xxxxxxxxxxx>]

Thank you for explanation
I have read the code ,and want to comfirm some confusion,and then try to 
write something new,if nessary
the shadow pagetable on demand ,means a whole pagetable copy when the 
process is scheduled, or just a part of the process's pagetable is copied
thanks in advance
cheers

Tim Deegan åé:
> 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.
>
>   

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