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Re: [Xen-devel] PV guest + shadow paging



Hi,

At 19:01 +0800 on 22 Oct (1193079674), tgh wrote:
> what is the auto_translated_physmap ?

A shadow pagetable mode where Xen does the translation between
guest-physical and machine-physical addresses for PV guests.  Normally
PV guests do that translation themselves, because it's faster, and Xen
does it for HVM guests because they can't do it themseves.

> how does it work?

It doesn't, at least not in xen-unstable.  As I said, I believe some
research projects have it working in their own trees because it's useful
for things like deterministic replay of guest execution.

> and what about 
> other mechanisms and how many mechanisms for paging are there in xen ?

Plenty.  There are between two and eighteen shadow modes, depending on
how you'd like to count them, hardware support for using two sets of
pagetables at once, normal PV guest paging, writeable pagetables, grant
tables for letting one guest see another guest's pages, and IOMMU
support for paging DMA.  Probably one or two more in there somewhere.

Tim.

-- 
Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>, XenSource UK Limited
Registered office c/o EC2Y 5EB, UK; company number 05334508

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