Re: dom0 pvh, old projects

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sat, Sep 14, 2024 at 01:30:50PM -0400, Greg Troxel wrote:
> (I am in the middle of updating to xenkernel418-20240909.)
> 
> 1) pvh dom0
> 
> I tried to boot a dom0 pvh, with older xenkernel418.  My dom0 is
> up-to-date netbsd-10 (well, from September 2).  xen booted and then I
> got a blank screen and hang when transferring to NetBSD.
> 
> The boot lines that work (PV) and hang (PVH) are:
> 
> menu=Xen PV:gop 6;load /netbsd-XEN3_DOM0.gz bootdev=dk1 rndseed=/var/db/entropy-file console=pc;multiboot /xen.gz cet=no-ibt console=vga dom0_mem=12000M
> menu=Xen PVH:gop 6;load /netbsd bootdev=dk1 rndseed=/var/db/entropy-file console=pc;multiboot /xen.gz cet=no-ibt console=vga dom0=pvh dom0_mem=12000M

My boot line is similar:
menu=Boot Xen:load /netbsd root=ld0 console=pc;multiboot /xen-debug.gz dom0_mem=24G console=vga dom0=pvh

But I also have
userconf=disable i915drmkms*
userconf=disable nouveau*
userconf=disable radeon*

And my kernel config file is:
include "arch/amd64/conf/GENERIC"

# DRMKMS driver
no i915drmkms*     at pci?
no radeon*         at pci?
no nouveau*        at pci?
no options      DRM_LEGACY

options         DOM0OPS
pseudo-device  xenevt
pseudo-device  xvif
pseudo-device  xbdback

no options DDB_COMMANDONENTER
#options DDB_COMMANDONENTER="trace"


> 
> I am not 100% certain I booted from /netbsd, but I have been booting
> from a July netbsd-10.
> 
> I know this is experimental.  Anything wrong with my boot.cfg line?

dom0 PVH is still mentionned as experimental on the Xen side for 4.18,
and "suppported with caveats" for 4.19 and 4.20:
https://xenbits.xen.org/docs/unstable/support-matrix.html

They also say:
PVH dom0 hasn't received the same test coverage as PV dom0, so it can exhibit unexpected behavior or issues on some hardware.

At least the following features are missing on a PVH dom0:

    PCI SR-IOV and Resizable BARs.
    Native NMI forwarding (nmi=dom0 command line option).
    MCE handling.
    PCI Passthrough to any kind of domUs.

On the NetBSD side it has received even less testing.

> 
> 2) There are wiki projects that look old.
> 
> https://wiki.netbsd.org/projects/project/xen-domU-pvops-pvh/

This one is completed AFAIK

> https://wiki.netbsd.org/projects/project/xen-dom0-pvh/

What is described here is also complete. 

So I guess both should be deleted.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--