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] Re: xen crash in tmem: checking a xen pfn for domain own

To: "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx>, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx>
Subject: Re: [Xen-devel] Re: xen crash in tmem: checking a xen pfn for domain ownership
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: Mon, 20 Sep 2010 08:16:57 +0100
Cc: Xen-devel <Xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Mon, 20 Sep 2010 00:17:51 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C8B980F6.6C37%keir.fraser@xxxxxxxxxxxxx>
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: <C8B96331.23693%keir.fraser@xxxxxxxxxxxxx> <C8B980F6.6C37%keir.fraser@xxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>>> On 17.09.10 at 21:32, Keir Fraser <keir.fraser@xxxxxxxxxxxxx> wrote:
> Oh, depending on what you want to do with the page you may well want to
> get_page(current->domain, page). You don't hold a lock on the domain's p2m,
> so page ownerships can change under your feet, and hence getting a reference
> to the page, and checking the page's ownership at the same time, might be
> wise. And if you want to modify the page you should probably use
> get_page_and_type(..., PGT_writable_page).

That's particularly important for the pv case, where gfn_to_mfn() is
a no-op.

Jan


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