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] I cannot get any message from domU by console / pv_ops d

To: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Subject: Re: [Xen-devel] I cannot get any message from domU by console / pv_ops domU kernel crashes with xen_create_contiguous_region failed
From: Michael D Labriola <mlabriol@xxxxxxxx>
Date: Tue, 22 Dec 2009 08:04:45 -0500
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>, xen-devel-bounces@xxxxxxxxxxxxxxxxxxx, ?????? <peb1611@xxxxxxxxx>
Delivery-date: Tue, 22 Dec 2009 05:05:12 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <1261473615.5965.3829.camel@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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote on 12/22/2009 04:20:15 AM:

> On Tue, 2009-12-22 at 08:42 +0000, Pasi Kärkkäinen wrote:
> > >    (early) [    0.000000] PCI-DMA: Using Xen software bounce
> > buffering for IO
> > >    (Xen-SWIOTLB)
> > >    (early) [    0.000000] Kernel panic - not syncing:
> > >    <3>xen_create_contiguous_region failed
> > > 
> > 
> > Did you try cgroup_disable=memory kernel option? 
> I think this is more likely to relate to the failure to initialise
> swiotlb due to the failure of xen_create_contiguous_region, leading to a
> panic. IIRC the guest won't be privileged enough to make this call
> unless it has PCI passthrough enabled.
> In a pre-pvops kernel the swiotlb would be inactive in a domU unless
> specifically requested on the command line but in Jeremy's xen/master
> branch it looks like it is unconditionally enabled for dom0 and domU as
> a consequence of:
>         commit 4bc6b1a9dd5d7447af8c3d27c1449f73f5f764ec
>         Author: root <root@xxxxxxxxxxxxxxxxxxxxx>
>         Date:   Thu Nov 5 16:33:10 2009 -0500
>             Enable Xen-SWIOTLB if running in [non-]privileged and 
> disable the Xen-IOMMU if an IOMMU is detected.
> On a related note I don't think the xen-swiotlb code should panic() if
> it cannot allocate the contiguous region (at least in domU). Chances are
> if it hasn't got privilege to make the fixups it isn't going to have any
> devices.

I ran into the same problem yesterday, traced it back to that exact 
commit.  Reverting it makes my domUs work, but feels like the wrong thing 
to do.  How do I make sure xen_create_contiguous_region is privileged 
enough?  I've got the PCI frontend and backend  built in to my kernel 
(used the x86 fedora .config from the pv_ops wiki).


Xen-devel mailing list

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