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[Xen-devel] page fault handling in Xen

To: xen-devel@xxxxxxxxxxxxxxxxxxx, xen-users@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] page fault handling in Xen
From: jeet <jeet_sat12@xxxxxxxxxxx>
Date: Fri, 2 Mar 2007 14:39:49 +0530 (IST)
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Hi All,

I am trying to understand Shadow page fault handling in Xen for x86_64 in Intel 

As per my understanding when guest can update it own page table without causing 
VM exit in xen

when some process requires some memory (pages) this will cause page fault and 
control goes to guest OS
the guest then allocate page from its own psuedo address space and make entries 
in guest page table which contain
mapping of virtual to psuedo physical memory and

But when actual write occurs to that page, page fault occurs which will cause 
vm exit in xen.

Xen then will update the page mfn in shadow page table and return control back 
to guest by vn entry.

Is this understanding it correct? so there would be only one vn exit/entry?

please do reply back 

Thanks in advance


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