Re: [Xen-users] Re: Update the kernel?

["Steven Maresca" <lightyear4@xxxxxxxxx>]

Please forgive the format of this message (or lack thereof); it is a
rough summary of the things I've collected about paravirt ops and xen.

Largely the work of Jeremy Fitzhardinge of Xensource/Citrix (and
lately Ian Cambell), the xen paravirt_ops implementation is functional
for domUs and in rapid development for dom0.

The vanilla kernel.org linux kernel can (today, and since .23-ish) be
compiled as a xen domU kernel.  Partial compile considerations are
present in the xen wiki at
http://wiki.xensource.com/xenwiki/Kernel.org_Linux_on_Xen -- that
said, if you fire up make menuconfig  and search for XEN, you'll see
all of the required config flags to make an unprivileged guest.  Note:
High Memory Support/PAE is required for 32bit; if not enabled, the xen
stuff will be masked. The 'Processor type and features' menu contains
'Paravirtualized guest support' where Xen guest support will exist as
an option if preconditions are met.

Required reading on the "State of Xen in Upstream Linux" is here, from
July. http://lists.xensource.com/archives/html/xen-devel/2008-07/msg01426.html
As stated in that post to xen-devel, Jeremy was originally aiming for
(in july) for a dom0 kernel with 2.6.28, which is now in RC.
That said, and per this more recent post,
http://lists.xensource.com/archives/html/xen-devel/2008-11/msg00205.html
the current target is .29

For general information, see http://wiki.xensource.com/xenwiki/XenParavirtOps.
OId, still partly relevant information can be found here
http://xenbits.xensource.com/ext/paravirt_ops/

Jeremy Fitzhardinge's patch queue is here
http://xenbits.xensource.com/paravirt_ops/patches.hg/
As noted in the previous portion of the thread, the bulk of xen dom0
patches were submitted to upstream linux for consideration just
recently. See 
http://lists.xensource.com/archives/html/xen-devel/2008-11/msg00268.html

Upstream comments and progress on xen can be seen here
http://marc.info/?l=linux-kernel&w=2&r=1&s=xen&q=b

Xen Summit June 2008 Paravirt ops presentation here
http://www.xen.org/xensummit/xensummit_summer_2008.html (definitely
check this out)
A note: early dom0 paravirt ops work was performed by Stephen Tweedie
and Mark McLoughlin of redhat/fedora, probably Dan Berrange in some
respects as well, though I cannot recall.  Some of their work remains
to be merged with the current efforts.


Very general guide to compiling:
Pull from Ingo Molnar's git tip and jeremy's patches. Following the
order of patches contained in the 'series' file, first apply the x86
patches and then the xen patches.

If the tree is in a consistent state - i.e. jeremy et al left it in at
least a state capable of compilation (devs need sleep too) - then you
can at minimum compile a dom0 kernel based upon the current upstream
which runs your system for userspace, etc if not a guest. That said,
ongoing blktap work has permitted guests to boot, though I do not know
if new changes have introduced issues preventing that.

Well, that was a very dense spew of information, some gross
generalizations and repetition, but I hope that this helps someone.

Steve Maresca
steve [at] zentific.com


On Wed, Nov 19, 2008 at 3:00 PM,  <xen-users-request@xxxxxxxxxxxxxxxxxxx> wrote:
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> Today's Topics:
>
>   1. Re: Backup (Paras pradhan)
>   2. Setting CPU (core) frequency from dom0 (Alberto Munoz)
>   3. RE: GPLPV 0.9.12-pre4 uploaded (Venefax)
>   4. Re: Re: Update the kernel? (jonr@xxxxxxxxxx)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 19 Nov 2008 12:40:10 -0600
> From: "Paras pradhan" <pradhanparas@xxxxxxxxx>
> Subject: Re: [Xen-users] Backup
> To: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
> Cc: Xen Users <xen-users@xxxxxxxxxxxxxxxxxxx>
> Message-ID:
>        <8b711df40811191040s127fe222pbbfb5513a0e1b6f1@xxxxxxxxxxxxxx>
> Content-Type: text/plain; charset="iso-8859-1"
>
> On Tue, Nov 18, 2008 at 8:16 PM, James Harper <james.harper@xxxxxxxxxxxxxxxx
>> wrote:
>
>> > hi all,
>> >
>> > What is the preferred method/tool to backup Xen guests?
>> >
>> > Xm save and DD seems to work but 'xm save' stops the virtual machine
>> and
>> > DD is slow.
>> >
>> > Any better option?
>> >
>> > I am under CentOS/DRBD
>> >
>>
>> I use Bacula and treat the VM's like normal computers.
>>
>> Alternatively you could use LVM to create a snapshot and back that up,
>> assuming you are using LVM in the first place.
>>
>> James
>
>
>
> Thank you all for the reply.
>
>
> Here's what I did:
>
> To backup:
>
> 1) Saved the virtual machines' state using:
>
> xm save guest01 /guest01.save
>
> 2) lvcreate -s -L 2G -n guest01-snap /dev/vg/guest01-disk
>
> 3) Restored the VM
>
> xm restore /guest01.save
>
> 4) Used DD to create the image
>
> dd if=/dev/vg/guest01-snap of=/guest01.img
>
> 5) lvremove /dev/vg/guest01-snap
>
> To restore:
>
> 1) I turned off the VM (i don't like this)
>
> xm shutdown guest01
>
> 2) Then run:
>
> dd if=/guest01.img of=/dev/vg/guest01-disk
>
> 3) Turn back the VM on
>
> --
>
> My virtual machine is consuming 11GB of space. Now when i do DD while
> restoring it took a lot of time.
>
>
> ---
> 10737418240 bytes (11 GB) copied, 1189.42 seconds, 9.0 MB/s
>
> ---
>
>
> Is this normal?
>
>
> I don't know if the process that I have used is fine or not. Need views on
> this.
>
>
>
> Thanks
>
> Paras.
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> ------------------------------
>
> Message: 2
> Date: Wed, 19 Nov 2008 10:50:12 -0800
> From: Alberto Munoz <amunoz0221@xxxxxxxxxxx>
> Subject: [Xen-users] Setting CPU (core) frequency from dom0
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Message-ID:
>        <fe5f99e40811191050m3cf00eb4wd5a522471962376@xxxxxxxxxxxxxx>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hello everyone,
>
> I am running some experiments that require changing the frequency of a CPU
> in a SunFire machine (32-core quad socket AMD Barcelona).
>
> For what I have found (bits and pieces but not a comprehensive description),
> there are two meachisms for controlling core (most probably socket)
> frequency in Xen:
>
> A- The older (xen-3.2.1) mechnism through dom0 (option cpufreq=dom0-kernel),
> which for what I gather uses a module in dom0 (cpufreqd?) that allows one to
> set cpu frequency.
>
> B- The newer (xen-3.3), which has moved the governor to the hypervisor
> (option cpufreq=xen), which other than a utility to read processor P and C
> states (xenpm) does not (yet) allow user (dom0) control of CPU frequency.
>
> My first question is whetherot what I have written above is accurate. My
> second question is where can I find detailed information on how to set up my
> system to make use of A above and be able to set cpu frequency "manually"
> from Dom0 (assuming that is still possible in Xen 3.3).
>
> I am running the latest testing version of Xen 3.3 (about a week old).
>
> Any information would be greatly appreciated.
>
> Thank you,
>
> Alberto
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> ------------------------------
>
> Message: 3
> Date: Wed, 19 Nov 2008 14:22:17 -0500
> From: "Venefax" <venefax@xxxxxxxxx>
> Subject: RE: [Xen-users] GPLPV 0.9.12-pre4 uploaded
> To: "'Innuendo'" <k.ader@xxxxxxxxxx>,   <xen-users@xxxxxxxxxxxxxxxxxxx>
> Message-ID: <027c01c94a7c$23e8cfb0$6bba6f10$@com>
> Content-Type: text/plain;       charset="US-ASCII"
>
> I just upgraded my win2k3 virtual machine from the Suse Drivers to pre-4,
> and while it works, my mouse now is several inches from the target, on the
> graphics console. Is there any workaround that would make the internal and
> external mouse work together?
> Yours
> Federico
>
> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Innuendo
> Sent: Wednesday, November 19, 2008 1:10 PM
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-users] GPLPV 0.9.12-pre4 uploaded
>
>
>
>
> James Harper wrote:
>>
>> I've just uploaded 0.9.12-pre4 to http://www.meadowcourt.org/downloads
>>
>
> Hi James,
>
> thx for your great work! I will give latest drivers a try next weekend.
> Before start a test, what's up with xm hotplug commands like block-attach
> and block-detach in latest build? Are they still bypassed or does latest
> driver handle hotpluggin, e.g. for cd-rom  media change purpose. Is
> Uninstall util now able to remove drivers and service completely?
>
> kindly regards
>
> --
> View this message in context:
> http://www.nabble.com/GPLPV-0.9.12-pre4-uploaded-tp20578814p20585803.html
> Sent from the Xen - User mailing list archive at Nabble.com.
>
>
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>
>
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 19 Nov 2008 10:58:47 -0900
> From: jonr@xxxxxxxxxx
> Subject: Re: [Xen-users] Re: Update the kernel?
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Message-ID: <20081119105847.4a7k4sx6fc40w440@xxxxxxxxxxxxxx>
> Content-Type: text/plain;       charset=ISO-8859-1;     DelSp="Yes";
>        format="flowed"
>
> Quoting Ferenc Wagner <wferi@xxxxxxx>:
>
>
>> There are published patches for 2.6.28, which make it possible to boot
>> it in dom0 and create (as yet unusable) domUs.  Devs hope something
>> like that will be merged into 2.6.29.  So it doesn't sound that far...
>> --
>> Regards,
>> Feri.
>>
>
> Are there a set of patches for a kernel that will allow the domU to
> work? I have been trying to find a Suse or Debian kernel with the
> patches but cannot seem to find them. Does anybody know where these
> are kept? I know I am probably missing the obvious so I will take the
> beating to get the info. :)
>
>
> Jon
>
>
>
>
>
>
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