Subject: Re: [vserver] Karmic guest problem with xorg and mtrr
From: "John A. Sullivan III" <jsullivan@opensourcedevel.com>
Date: Mon, 28 Dec 2009 16:48:50 -0500

On Mon, 2009-12-28 at 14:03 -0600, Michael S. Zick wrote: 
> On Mon December 28 2009, John A. Sullivan III wrote:
> > On Sun, 2009-12-27 at 05:01 -0600, Michael S. Zick wrote: 
> > > On Sun December 27 2009, John A. Sullivan III wrote:
> > > > Hello, all.  We are trying to install an Ubuntu Karmic amd64 guest onto
> > > > a CentOS 5.4 VServer host running kernel 2.6.28.7-vs2.3.0.36.7.  apt-get
> > > > install xserver-xorg is failing on configuration. We are seeing errors
> > > > such as: 
> > > > 
> > > > kernel: vxW: [XsysctlX,31495:#40042|40042|40042] denied 22 access to
> > > > proc:ffff8801b15ca7b0[#0,65478792]
> > > > 
> > > 
> > > By design, guests do not have access to the host hardware.
> > > 
> > > You can reduce the isolation provided to a guest by granting it the
> > > access to hardware and/or changing its capability sets.
> > > For X11, that is a whole lot of added capabilities to keep it happy.
> > > 
> > > Or you can run your graphics using non-hardware X11, such as VNC.
> > > 
> > > You should be able to find information on both solutions in the Wiki.
> > > 
> > > Mike
> > > > >From what I've seen on other threads, it seems like it is trying to do
> > > > something to /proc/mtrr.  We'll do battle with this on Monday but, if
> > > > someone knows what this is off the top of their head and can point us in
> > > > the right direction, we'd certainly appreciate it.  Thanks - John
> > <snip>
> > Thanks.  Just getting back to this now.  That is what we do - these are
> > virtual desktops which we deliver using NX either via NoMachine's or
> > X2Go's (www.x2go.org) implementation.  It worked fine under Hardy but
> > something must have changed in Karmic.  I'll keep digging and let the
> > list know what I find.  If anyone has already fought this battle, please
> > let me know! - John
> > 
> 
> Karmic uses a much newer kernel, complete with changes in the mtrr handling
> and a different version of X11 to match.
> 
> You should be able to run the Karmic installation with the older kernel (I think).
<snip>
Yes, I was concerned when I read that in the release notes and it may be
the problem.  We just failed again. It appears to be in the
auto-configuration for xserver-xorg.  I don't know much about the Debian
configuration magic but I'll have to dig deeper perhaps using strace as
Herbert suggested.  The sad thing is, we really don't need much X
support and certainly no hardware but apt is probably picking up a
dependency somewhere that we really don't need.  I'll keep digging.
Thanks - John