WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Intercepting memory operations of a guest

To: Sina Bahram <sbahram@xxxxxxxxx>
Subject: Re: [Xen-devel] Intercepting memory operations of a guest
From: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Date: Tue, 9 Dec 2008 10:09:11 +0000
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 09 Dec 2008 02:09:39 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <97E3D7A472E04436BB0AAD8EEC86CD6A@neutrino>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <DD171F58596F42818CD66D989CA2EAD4@neutrino> <20081208101217.GQ25331@xxxxxxxxxxxxxxxxxxxxx> <97E3D7A472E04436BB0AAD8EEC86CD6A@neutrino>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.17 (2007-11-01)
Hi,

At 11:54 -0500 on 08 Dec (1228737297), Sina Bahram wrote:
> What do you mean by the statement that it won't catch "all changes" but only
> those seen by the mmu?
 
You might not see changes made before a pagetable is used for the first
time, or after it stops being used.  Potentially you might miss other
changes as well.  But you are guaranteed that if any pagetable state is
ever seen by the hardware, (that is, used in a VA->PA translation) you
will have seen that state first.

> Also, where can I read more about what enabling shadow page tables means for
> pv guests?

Not much documentation, I'm afraid.  The source code has some comments
in it (xen/arch/x86/mm/shadow/*) and there's always the live-migration
paper for an overview, though implementation details there are quite out
of date:
http://www.cl.cam.ac.uk/research/srg/netos/papers/2005-nsdi-migration.pdf
 
Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Citrix Systems (R&D) Ltd.
[Company #02300071, SL9 0DZ, UK.]

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel