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Re: [Xen-devel] some questions about the HVM

To: WangWei???? <wangwei.cs@xxxxxxxxx>
Subject: Re: [Xen-devel] some questions about the HVM
From: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Date: Fri, 26 Mar 2010 16:58:56 +0000
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Hi, 

At 14:00 +0000 on 26 Mar (1269612028), WangWei???? wrote:
> I have a question about the VMEXIT in HVM.
> Does the behavior of modifying the pte of guest OS cause a vmexit.

When using shadow pagetables, yes (more precisely, modifying a page that
is shadowed causes a VMEXIT).  When using hardware-assisted paging (NPT
or EPT), no.

> If so ,the vmexit reason is page fault or something else ?

It's a page fault, because shadowed pages are always mapped read-only in
the shadow page tables.

Why do you want to know?

Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

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