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Re: [Xen-devel] Page tables in Xen

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? 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? 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?

Thanks in advance





Tim Deegan 写道:
At 20:12 +0800 on 05 Dec (1196885526), tgh wrote:
hi
in the PV mode,VM guestOS pagetable is virtual-to-machine address mapping,is it right?

Yes.

,and when a VM is migrated, the shadow page table mode will be enabled ,is it right?

Yes.

then, the PVguestOS pagetalbe will become the virtual-to-psuedophysical address mapping, or not?

Not.

then ,at that time ,the shadow pagetalbe is virtual-to-machine one ,is it right?

Yes.
I am still confused ,especially about the PVguestOS pagetalbe when shadow pagetable enabled for migration? is it a virtual-to-machine address mapping, or a virtual-to-psuedophysical address one ?

*All* shadow pagetables are virtual-to-machine translations.  Anything
else wouldn't be much use.

Cheers,

Tim.



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