Re: Recent XEN3_DOM0 begaviour

[Brad Spencer <brad%anduin.eldar.org@localhost>]

Chavdar Ivanov <ci4ic4%gmail.com@localhost> writes:

> Hi,
>
> I recently restored my earlier NetBSD/XEN setup on an old(ish) HP
> EliteBook laptop; it all went rather well using xen packages for 4.11.
> I then added a couple of disks to the system (one - the internal
> mSATA, the other - on the tray replacing the DVD) with the intention
> to use the second one as storage for XEN guests. I formatted this one
> as GPT and added a couple of disks:
> .....

[snip]

> It all works well, with the exception that when I reboot the host
> under XEN using the usual
>
> menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=2048M
>
> the kernel decides that it has been booted from dk0, instead of wd0,
> and I have to be present for the boot and point wd0 to be the boot
> disk (BTW if I point at this moment to dk1/dk0 I am able to boot the
> guest on bare metal using the same XEN3_DOM0 kernel... ).
>
> Is there any means to force XEN3_DOMU to use wd0 as boot device? This
> doesn't happen if I use the normal /netbsd kernel, it can see dk0/dk1
> but proceeds to booot from wd0 by default.
>
> Or perhaps I have to modify XEN3_DOM0 ?
>
>
> Chavdar


Yes, this is possible.  NetBSD is using the multiboot protocol to boot
Xen DOM0.  There is a man page at 'man 8 multiboot' or 'man 8
x86/multiboot'.  I used to have to use the root= option on previous
versions of my DOM0 systems, but have not had to do that recently due to
hardware reorgs.  If I remember things correctly, you should be able to
change your menu as follows:

menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc root=wd0a;multiboot /xen.gz dom0_mem=2048M

You may also want to add dom0_max_vcpus=1 as well.  The world will
likely be different once PVHVM is available, but for now, a DOM0 can not
use more than one CPU:

menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc root=wd0a;multiboot /xen.gz dom0_mem=2048M dom0_max_vcpus=1





-- 
Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS - http://anduin.eldar.org