Subject: Re: [vserver] Karmic guest problem with xorg and mtrr
From: Herbert Poetzl <herbert@13thfloor.at>
Date: Mon, 28 Dec 2009 21:31:30 +0100

On Mon, Dec 28, 2009 at 02:12:36PM -0500, 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

> 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.  

you shouldn't need a real x11 (hardware) for that, or
to be precise, it would make the whole virtual desktop
approach rather useless ...

> It worked fine under Hardy but something must have changed in Karmic.

probably everything changed ... strace is your friend

> I'll keep digging and let the list know what I find.

good luck,
Herbert

> If anyone has already fought this battle, please
> let me know! - John