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Re: [Xen-devel] create shadow pages

To: ding baozeng <baozengding@xxxxxxxxx>
Subject: Re: [Xen-devel] create shadow pages
From: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Date: Thu, 4 Nov 2010 12:44:01 +0000
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At 12:30 +0000 on 04 Nov (1288873804), ding baozeng wrote:
> I alloc some memory (some pages)in the hvm domU kernel space, but not
> map it. So the kernel space could not access the memory by its guest
> tables. But I would access it by shadow pages for some use.

Why can't you just map it with the guest pagetables?  Having it only in
the shadow pagetables would be confusing.  What if the guest kernel
wants to map something else at that virtual address?

> When the
> shadow pages are built, they should be in memory always and should not
> be paged out.  Then how to create the shadow pages for the memory?

The easiest thing would be to change guest_walk_tables to insert your
mappings as if they were in the guest pagetables.  That way all the
users in Xen will be consisitent.  



Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

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