Re: Booting a NetBSD 4 domU on a Linux dom0?

[Chris Ross <cross+netbsd%distal.com@localhost>]

On Mar 29, 2007, at 4:19 AM, Manuel Bouyer wrote:
> The changes to use a linux dom0 should only be marginal, and you'll  
> spot
> them easily (device names in the config file, mostly) if you  
> already have
> a linux domU running.

  Yup.  Tho the Linux domU's we're running are being fully  
virtualized, rather than having any knowledge of Xen.

> Running 32 or 64bit linux ? NetBSD/Xen only runs on 32bit hosts for  
> now.

  Ahh, okay then.  That'll be a stopper.  We're running a x86_64  
linux dom0 on these machines.  So, no domU's that aren't 64-bit, I  
presume.  (I mean, in theory you could make a 32-bit one work, but I  
can't imagine why the Xen folks would've.  ;-) )

> For Xen native domU, the kernel is loaded from dom0's filesystem.
> the disk/cdrom/whatever images used for virtual disks are only used  
> once
> the kernel is running.
> What you need to do the install is the netbsd-INSTALL_XEN3_DOMU.gz  
> kernel.
> Once the install is complete, halt the domU and boot it with
> netbsd-XEN3_DOMU.gz

  Cool.  If I get to the point where I can try this, I now know  
how.  Thanks much!

> This I don't know, I've never tried it on a 64bit OS. I ran NetBSD/ 
> i386
> on a para-virtualized guest on a i386 dom0, and it's as fast as a  
> native Xen
> guest for CPU-bound tasks. I/O are slow.

  Hmm.  I may be crossing terms here.  I think what I mean by  
paravirtualized is what you're calling "native Xen".  ie, a domU that  
knows it's on Xen and uses the hypervisor to get basically direct  
access to the hardware, rather than working through "virtual" devices.

> No, we don't have 64bit support in Xen yet.

  K.  That's something that's fully possible, right, just not yet  
working?  Is it something folks are working on?

  Thanks again for all of the information.  Much appreciated.

                                    - Chris