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] Xen support for AMD's IOMMU

To: "Mark Williamson" <mark.williamson@xxxxxxxxxxxx>, xen-users@xxxxxxxxxxxxxxxxxxx
Subject: RE: [Xen-users] Xen support for AMD's IOMMU
From: "Petersson, Mats" <Mats.Petersson@xxxxxxx>
Date: Mon, 26 Feb 2007 18:42:46 +0100
Cc: Daniel McAllansmith <dm.maillists@xxxxxxxxx>
Delivery-date: Mon, 26 Feb 2007 09:42:29 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <200702261740.13302.mark.williamson@xxxxxxxxxxxx>
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: AcdZzSGQI0d/MPUeRya1yKwrFArbUwAABFdA
Thread-topic: [Xen-users] Xen support for AMD's IOMMU
 

> -----Original Message-----
> From: M.A. Williamson [mailto:maw48@xxxxxxxxxxxxxxxx] On 
> Behalf Of Mark Williamson
> Sent: 26 February 2007 17:40
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Cc: Petersson, Mats; Daniel McAllansmith
> Subject: Re: [Xen-users] Xen support for AMD's IOMMU
> 
> > > What is the status of support for AMD's (hardware/Pacifica)
> > > IOMMU in xen
> > > 3.0.2/3/4?
> >
> > Considering that we haven't yet got a part available with IOMMU, the
> > software to fullfill that function is pretty much a moot 
> point, right?
> 
> There's some sort of memory permissions table for PCI devices 
> though, isn't 
> there?  I vaguely remember it being in the arch manual, but I haven't 
> actually known any software use it (at least in the context of Xen!)

Yes, that's called "DEV" or "Device Exclusion Vector", and I'm also
unaware of any software that is commonly available that uses this. It
doesn't actually solve the most commonly requested feature in IOMMU,
which is the ability to run a HVM-guest using a PCI-device, and I wasn't
really considering the "security aspect" of IOMMU when I wrote my answer
[and the DEV feature is definitely not usable to solve the PCI-device in
HVM problem]. 

--
Mats
> 
> Cheers,
> Mark
> 
> > As to a direct answer to the question: There is no AMD 
> IOMMU software in
> > 3.0.{2,3,4}. There's been a patch supplied by Mark 
> Langsdorf to use the
> > GART in the current AMD64 architecture for IOMMU operations 
> (same way as
> > the Linux kernel itself uses this portion of the chip). 
> This is NOT to
> > be confused with the REAL IOMMU design.
> >
> > --
> > Mats
> >
> > > Thanks
> > > Daniel
> > >
> > > _______________________________________________
> > > Xen-users mailing list
> > > Xen-users@xxxxxxxxxxxxxxxxxxx
> > > http://lists.xensource.com/xen-users
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
> 
> -- 
> Dave: Just a question. What use is a unicyle with no seat?  
> And no pedals!
> Mark: To answer a question with a question: What use is a skateboard?
> Dave: Skateboards have wheels.
> Mark: My wheel has a wheel!
> 
> 
> 



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