|   xen-users
Re: [Xen-users] Xen as virtual KVM 
| 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.  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!
 
 
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