Re: Problems booting netbsd DOM0 (and domU!)

[Greg Troxel <gdt%lexort.com@localhost>]

"Greg A. Woods" <woods%planix.ca@localhost> writes:

> At Wed, 27 Dec 2023 16:49:47 -0800, "Greg A. Woods" <woods%planix.ca@localhost> wrote:
> Subject: Re: Problems booting netbsd DOM0 (and domU!)
>>
>> Which brings me to realize "dom0=msr_relaxed" on the Xen command line
>> should have allowed the older XEN3_DOM0 kernel to boot, and I thought I
>> had tried that but it didn't work (though perhaps I got the syntax wrong).
>
> I can now confirm that "dom0=pv,msr-relaxed=1" on the Xen command line in
> /boot.cfg will allow an older unpatched NetBSD XEN3_DOM0 kernel to boot!
>
> This should greatly ease the upgrade path for anyone trying to update
> Xen on a machine still running legacy NetBSD kernels.

For the HOWTO, is the dom0=pv part necessary?  I would think this is the
default.


I think the text to be added is:

  When the dom0 kernel is NetBSD 8 and earlier, and NetBSD 9 before
  2021-04-17 (9.3 is ok), Xen 4.15 and later require
  "dom0=msr-relaxed=1" on the boof.cfg line.  (See
  /src/sys/arch/x86/x86/pmap.c revision 1.410.)

Is that right?