RE: [Xen-users] Xen as virtual KVM

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

> -----Original Message-----
> From: M.A. Williamson [mailto:maw48@xxxxxxxxxxxxxxxx] On 
> Behalf Of Mark Williamson
> Sent: 26 June 2007 18:25
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Cc: Petersson, Mats; Brandon Reno
> Subject: Re: [Xen-users] Xen as virtual KVM
> 
> > 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).

Good idea. But isn't "full-screen" broken at the moment (not sure if it
ever worked) on HVM domains?

--
Mats
> 
> 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!
> 
> 
> 



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