Re: [Xen-users] Xen as virtual KVM

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

> Pretty good idea, the original theory was to have the dom0 "invisible" to
> the end-user, but I think that this would work well enough.

How about you log into the dom0 using the default X server, but run all the 
virtual machines on a separate X server...  e.g. set up a script something 
like:

#!/bin/sh

X :1 # start X server on display 1
compiz-fusion -display :1 # or whatever you type ;-)

vncviewer blah blah foo # repeated for each VM to start viewer on each desktop

You can then switch between the "dom0" X server, and the X server viewing all 
the domUs using Alt+F7, Alt+F8.  And between the desktops on the domU display 
using ctrl-alt-left/right, with a spiffy cube rotation effect ;-)

Obviously, this is all still running in dom0 so it isn't quite what you 
wanted.  But it should look pretty awesome, and you can use it with both HVM 
and paravirtualised guests.  If you ever get it working, it'd be great to see 
a video of "OS switching" on Youtube ;-)

Cheers,
Mark

> Even if the 
> virtual framebuffer doesn't support full screen, it would be possible to do
> this with either VNC or simple XDM/Rdesktop.
> It would work 'well enough' for our purposes at this time, and if I really
> need high performance video, I can always do it within the dom0.
>
> I'll keep an eye out for the expanded support for HVMs and PCI-passthrough.
>
> On 6/26/07, Mark Williamson <mark.williamson@xxxxxxxxxxxx> wrote:
> > > Just so that you understand it: It's perfectly possible to use ALL
> > > versions of OS's as HVM domains, so you could just set up your Linux
> > > and Windows domains to use HVM all the way - the graphics may not be as
> > > snappy as you get on real hardware, but it's definitely usable for
> > > testing purposes. And the advantage here is that you don't need any
> > > "messing about", and you can even leave all of them running at once and
> > > just click on the task-bar for which one you want to run at any given
> > > time (or run several in parallel - you just can't see all of them if
> > > you don't have a HUGE display on Dom0).
> >
> > In fact, you could try running a virtual machine display full screen on
> > each
> > virtual desktop, then switch between them using ctrl+alt+left/right -
> > that way you can have a different OS on each side of a cube (and be able
> > to zoom
> > out and look at all of them at once).
> >
> > Cheers,
> > Mark
> >
> > > --
> > > Mats
> > >
> > > > On 6/26/07, Petersson, Mats <Mats.Petersson@xxxxxxx> wrote:
> > > >     > -----Original Message-----
> > > >     > From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
> > > >     > [mailto: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
> > > >
> > > > <mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx> ] On Behalf Of
> > > >
> > > >     > Brandon Reno
> > > >     > Sent: 26 June 2007 15:28
> > > >     > To: xen-users@xxxxxxxxxxxxxxxxxxx
> > > >     > Subject: [Xen-users] Xen as virtual KVM
> > > >     >
> > > >     > I'm looking at doing something that may seem a little bit
> > > >     > odd, I would like to use xen to virtualize several desktop
> > > >     > environments, with a specific keystroke configured to switch
> > > >     > to that environment.
> > > >     > I will have either gentoo or debian as a dom0.  this will be
> > > >     > used only for management of the virtual machines.
> > > >     > I will have several full desktop environments for
> > > >
> > > > different users.
> > > >
> > > >     > For example, I will be using Gentoo with KDE/Beryl (soon to
> > > >     > be Fusion or whatever they are changing their name to)
> > > >     > I'd like to have a test environment for various trials of
> > > >     > different other flavours and for development
> > > >     > Additionally, I will be buying a new computer, supporting
> > > >     > AMD-V, will want to have 3 additional environments, Windows
> > > >     > XP and Vista, for application testing, and one
> > > >
> > > > Windows DE for my Wife.
> > > >
> > > >     > To accellerate as much as possible the different
> > > >     > environments,  I would need to setup the PCI video card to
> > > >     > passthrough to whichever domU is active.  It is not necessary
> > > >     > for more than one environment to be active and running at any
> > > >     > given time.
> > > >     > My theory is to simply configure each environment to pass
> > > >     > through the video card, and drop one environment (suspend?),
> > > >     > and switch to the next.  Do you see any problems with this
> > > >     > configuration, or have any advice?
> > > >
> > > >     You can do it with VNC/SDL in fully-virtual domains
> > > > with a virtual
> > > >     graphics card. That's a (nearly) no-brainer.
> > > >
> > > >     But unless you have at least two graphics cards in the
> > > > machine, Dom0
> > > >     will need to own the graphics card - it uses the VGA as
> > > > console during
> > > >     startup at the very least. So you need a second
> > > > graphics card to start
> > > >     with. I've seen complaints that pass-through of
> > > > graphics doesn't work,
> > > >     but don't take my word for it.
> > > >
> > > >     Using PCI passthrough, you would definitely have to
> > > > suspend ("xm save")
> > > >     the domain and resume another ("xm resstore") when
> > > > switching from one
> > > >     domain to another. Note that this takes several seconds
> > > > per save/restore
> > > >     cycle for any reasonable size domain - just writing
> > > > 128MB to the disk at
> > > >     50MB/s takes 2.5s or so, and there is more work than
> > > > this involved in
> > > >     the save-process.
> > > >
> > > >     HVM domains (Windows for example) can't use PCI
> > > > passthrough, at all, at
> > > >     this time (there's work to allow ONE instance of
> > > > Windows to do that -
> > > >     but that's still some way off, and I wouldn't rely on
> > > > this for the next
> > > >     3-6 months at least, although I'm not sure how far off
> > > > it really is).
> > > >
> > > >     > Additionally, I would need to write a program or series of
> > > >     > scripts to manage the switching of DEs, which doesn't seem to
> > > >     > be too much of a problem, except that it would need to
> > > >     > capture a few specific keystrokes (i.e. win+f1 thru win+f5)
> > > >     > to actually call the switch.
> > > >
> > > >     Why? What's wrong with clicking buttons/menus or typing
> > > > into a window
> > > >     someplace?
> > > >
> > > >     > I'm not sure where I would need to start to do this should
> > > >     > this program monitor /dev/input for the keypress, or would
> > > >     > this need to go into the hypervisor?
> > > >
> > > >     That's a good question - Dom0 doesn't (strictly) own
> > > > the keyboard, but
> > > >     you'd certainly have an easier task intercepting this
> > > > in Dom0 than you'd
> > > >     have in the Hypervisor, since the hypervisor won't
> > > > actually be able to
> > > >     make the switch happen anyways, so you NEED to get to
> > > > Dom0 someway
> > > >     anywyas to achieve this.
> > > >
> > > >     --
> > > >     Mats
> > > >
> > > >     > I currently have a few VMs on my server computer running
> > > >     > things like a webserver, samba share, Kerberos
> > > >     > Authentication, etc. and have been very happy with xen.  I'd
> > > >     > like to take the chance to document my findings on this
> > > >     > unique setup in case someone else would be interested.
> > > >     >
> > > >     > Any advice would be appreciated, or better yet, if someone
> > > >     > has done something like this, I'd like to hear about their
> > > >     > successes/failures.
> > > >     > Thanks,
> > > >     > Brandon Reno
> > >
> > > _______________________________________________
> > > Xen-users mailing list
> > > Xen-users@xxxxxxxxxxxxxxxxxxx
> > > http://lists.xensource.com/xen-users
> >
> > --
> > Dave: Just a question. What use is a unicyle with no seat?  And no
> > pedals! Mark: To answer a question with a question: What use is a
> > skateboard? Dave: Skateboards have wheels.
> > Mark: My wheel has a wheel!



-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users