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[Xen-devel] [Shadow Paging] Clarification Guest Paging Table Write Prote

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Subject: [Xen-devel] [Shadow Paging] Clarification Guest Paging Table Write Protection
From: Amit Dang <amitdang@xxxxxxxxxxx>
Date: Thu, 30 Apr 2009 13:52:07 +0000
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    I am new to Xen and trying to understand how Shadow Paging works. I require clarification on following point:

How does Xen write protects guest page table?
What I could understand reading code & other sources is that, when ever cr3 gets updated, control gets transferred to the hypervisor which then does the emulation for the instruction and write protects the guest page table. But the confusion is, cr3 contains Pseuso-physical address of the guest page table, but to protect this page protection bit is required to be set in its page table entry. How does Xen get page table entry for the address in cr3?

Thanks in advance,

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