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-users

RE: [Xen-users] AMD or Intel?

To: "lists" <lists@xxxxxxxxxxxxx>
Subject: RE: [Xen-users] AMD or Intel?
From: "Petersson, Mats" <Mats.Petersson@xxxxxxx>
Date: Fri, 25 May 2007 12:51:04 +0200
Cc: xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Fri, 25 May 2007 03:50:57 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <4656BB09.8040108@xxxxxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: Aceet+v6Na/EKrs2SH23vBTSDtwbMQAAfcZw
Thread-topic: [Xen-users] AMD or Intel?
> On a somewhat related topic, my understanding is that 
> Barcelona/K10 will
> provide hardware (IO-MMU?) that will allow expansion cards (PCI, AGP,
> PCIe, etc.) to be virtualised. Currently, if an expansion card were to
> attempt to access RAM in a guest it would be accessing the RAM at that
> address in the host, i.e., memory accesses in guests are not mapped to
> the appropriate memory in the host. Is it true that Barcelona/K10 will
> provide functionality to solve this problem? If so, has any work been
> done on supporting this hardware in Xen?

Sorry to disappoint, the upcoming "barcelona" core will have some
improvements to the AMD-V implementation, in particular the nested
paging feature, but I can clearly say that it doesn't have IOMMU.

Nested paging allows the guest to run without intercepts of the
page-table-updates, avoiding the code handling "shadow paging"
altogether. It will speed up most HVM guests, particularly those that do
a lot of page-table updates (such as creating/destroying processes a lot
- kernel compile for example). 

The work to support IOMMU in Xen will happen when we're closer to having
hardware with support for this. 

I'm not entirely sure (nor could I really tell anyone anyways) when the
IOMMU will be available, but it's very unlikely to happen this year, I
would think. 

--
Mats



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

<Prev in Thread] Current Thread [Next in Thread>