Re: dom0 pvh, old projects

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

Manuel Bouyer <bouyer%antioche.eu.org@localhost> writes:

>> 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*

A good hint but my hardware is too new to have anything recognized:

  genfb0 at pci0 dev 2 function 0: Intel Alder Lake Graphics (32EU) (rev. 0x0c)
  genfb0: framebuffer at 0x4000000000, size 1920x1200, depth 32, stride 7680
  wsdisplay0 at genfb0 kbdmux 1: console (default, vt100 emulation)
  wsmux1: connecting to wsdisplay0
  drm at genfb0 not configured

> 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"

So:

  - It seems DOM0OPS is necessary and that makes sense.

    + Will GENERIC with DOM0OPS still boot bare metal?
    + Should it be in GENERIC?
    + Should we have XEN3_DOM0PVH with this defined?

  - The other pseudodevices are the dom0 halves of the pv ops.
  
    + Will GENERIC with these still boot bare metal?
    + Should they be in GENERIC?
    + Should we have XEN3_DOM0PVH with this defined?

(Or maybe alternatively a DOM0PVH.include that has them, for people to
add?)

> 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.

Thanks!  Added to the howto.

>> 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.

I have used my [magic wand](cvs rm -f) and they are gone.