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/
Home Products Support Community News


Re: [Xen-devel] [PATCH] Add new location of Linux direct-map to theplace

To: Ian Pratt <Ian.Pratt@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Add new location of Linux direct-map to theplaces to look for writable mappings
From: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Date: Mon, 15 Sep 2008 09:31:55 +0100
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>, xen-devel mailing list <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Mon, 15 Sep 2008 01:32:23 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <DD74FBB8EE28D441903D56487861CD9D35C65107@xxxxxxxxxxxxxxxxxxxxxx>
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: <de76405a0809120838kee79064s6e81254a6ad0ebce@xxxxxxxxxxxxxx> <46f44832-0241-48ff-a6d2-d278003d42a1@default> <DD74FBB8EE28D441903D56487861CD9D35C65107@xxxxxxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.17 (2007-11-01)
At 20:19 +0100 on 12 Sep (1221250763), Ian Pratt wrote:
> What would also be interesting would be a shadow pagetable mode that
> stored 'back pointers' to enable one to easily find all the shadow PTEs
> that point to a page. This would be useful for some of the more fancy
> shadow pagetable modes that are interesting from a research POV, as well
> as coping with guests that use some other mechanism for updating PTEs
> (if such guests exist).

ISTR we decided not to do this when we were planning shadow2, because it
doubles the memory overhead and adds extra bookkeeping to the fast
paths.  Not to say it wouldn't be interesting, though. :)


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

Xen-devel mailing list