Re: [Xen-users] Debian Repository

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Wed, Jan 13, 2010 at 10:56:04AM -0000, Ian Tobin wrote:
> Sorry im a bit confused, why have they added DomU support but no Dom0 
> support?  
>

It's a long story. The 'original' Xenlinux patches (around Linux 2.6.18 
timeframe, 
including dom0 support) were submitted for inclusion in upstream Linux,
but the patches were considered too intrusive, ie. they modified too
much non-Xen generic x86 code, so the patches were not accepted into Linux.

That's when Xensource, VMware etc started working on a general
paravirtualization framework for Linux. This was called pv_ops (paravirt_ops). 
It took a long time to get the generic pv_ops framework in shape and merged in 
Linux, 
and then after that Xen pv_ops domU support was merged in mainline Linux.

See here for history/changelog: http://wiki.xensource.com/xenwiki/XenParavirtOps

Today upstream/mainline Linux contains Xen domU support using the pv_ops 
framework.

> I was under the impression that pv_ops replaces Dom0 and you can run domU on 
> pv_ops?
> 

Jeremy (from Citrix/Xensource) is working on adding dom0 support to
Linux pv_ops, so that mainline Linux can function as a dom0 kernel.

Currently pv_ops dom0 patches are in Jeremy's git tree, and not yet
accepted into upstream Linux. Jeremy is working hard on this.

See XenParavirtOps wiki page for status updates.

> That saying do i need a Dom0 if using pv_ops ?
> 

Uhm.. you always need dom0 to manage and run Xen.
Dom0 kernel can be based on pv_ops, or the old 'xenlinux' patches.

Hopefully that clears it up.

-- Pasi

> Ian
> 
> -----Original Message-----
> From: Pasi Kärkkäinen [mailto:pasik@xxxxxx] 
> Sent: 13 January 2010 09:59
> To: Ian Tobin
> Cc: xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-users] Debian Repository
> 
> On Wed, Jan 13, 2010 at 09:30:52AM -0000, Ian Tobin wrote:
> > Just another quick one, if i downloaded the latest kernel from kernel.org 
> > and compiled it would this have support for the latest XEN release?
> > 
> 
> vanilla kernel from kernel.org has Xen domU (guest) support included,
> using the Linux pv_ops framework.
> 
> Dom0 support is not yet included in kernel.org kernels.
> 
> List of various dom0 capable kernels and patches here:
> http://wiki.xensource.com/xenwiki/XenDom0Kernels
> 
> -- Pasi
> 
> > 
> > 
> > -----Original Message-----
> > From: Pasi Kärkkäinen [mailto:pasik@xxxxxx] 
> > Sent: 13 January 2010 09:23
> > To: Ian Tobin
> > Cc: xen-users@xxxxxxxxxxxxxxxxxxx
> > Subject: Re: [Xen-users] Debian Repository
> > 
> > On Wed, Jan 13, 2010 at 09:07:17AM -0000, Ian Tobin wrote:
> > > If Debian is not going to be supported for much longer what would the 
> > > next best OS be?
> > >
> > 
> > If you read the posts, they're actively working on fixing the packages.
> > 
> > -- Pasi
> > 
> > > 
> > > 
> > > -----Original Message-----
> > > From: Pasi Kärkkäinen [mailto:pasik@xxxxxx] 
> > > Sent: 12 January 2010 14:20
> > > To: Ian Tobin
> > > Cc: xen-users@xxxxxxxxxxxxxxxxxxx
> > > Subject: Re: [Xen-users] Debian Repository
> > > 
> > > On Tue, Jan 12, 2010 at 04:16:31PM +0200, Pasi Kärkkäinen wrote:
> > > > On Tue, Jan 12, 2010 at 12:44:32PM -0000, Ian Tobin wrote:
> > > > >    Hi,
> > > > > 
> > > > > 
> > > > > 
> > > > >    Im trying to install Netware and Windows 2008 server but im having
> > > > >    problems with it reading the ISO.  Im guessing this is because im 
> > > > > running
> > > > >    version 3.2.1 debian packages so i want to upgrade to unstable and 
> > > > > use the
> > > > >    3.4 deb packages.
> > > > > 
> > > > > 
> > > > > 
> > > > >    My problem is that there isn't a kernel package so when booting 
> > > > > you cant
> > > > >    boot into xenified kernel mode.  If i try and use a kernel from 
> > > > > the stable
> > > > >    tree it messes things up.
> > > > > 
> > > > > 
> > > > > 
> > > > >    How is everyone else running the 3.4 packages? Ive read about 
> > > > > pv_ops but i
> > > > >    don't know how to install or use it.
> > > > > 
> > > > > 
> > > > > 
> > > > >    Any ideas?
> > > > > 
> > > > 
> > > > I think the Debian Xen 3.4.2 debs are also missing qemu-dm required
> > > > for Xen HVM guests. 
> > > > 
> > > > Debian developers are working on adding qemu-dm back to the packages 
> > > > (it was removed because the Debian Xen maintainer didn't want to 
> > > > maintain
> > > > it, he thought managing/patching Qemu was too much work for him).
> > > > 
> > > > There was discussion about this on xen-devel and on debian pkg-xen
> > > > mailinglists:
> > > > 
> > > > http://lists.xensource.com/archives/html/xen-devel/2009-12/msg00716.html
> > > > and
> > > > http://blog.xen.org/index.php/2009/12/15/support-to-be-removed-from-debian-squeeze-call-for-volunteers/
> > > > 
> > > > You could always compile your own Xen dom0 kernel, there are many
> > > > options for that:
> > > > 
> > > > http://wiki.xensource.com/xenwiki/XenDom0Kernels
> > > > 
> > > 
> > > At the moment Linux 2.6.31.9 with OpenSUSE 2.6.31-10 Xen patches might
> > > be a good option for you as a dom0 kernel.
> > > 
> > > -- Pasi
> > > 
> > > 
> > > 
> > 
> > 
> 
> 

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