NetBSD 10.0 RC1 PVH and XenServer/XCP

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

I'm testing NetBSD 10.0 RC1 on Citrix Hypervisor 8.2 CU1 with uEFI boot 
mode. I don't expect any difference on XCP or the upcoming new XenServer 8 
release.

I got a few hints from Chavdar's 2020 post:
http://mail-index.netbsd.org/port-xen/2020/05/03/msg009719.html

The default settings of the Other install media VM template sets 
platform:vidirian=true. With vidirian=true:

- ld0 at nvme0 is detected (nvme0 at pci0 dev 7 function 0: Intel product 
5845 (rev. 0x02))
- wm0 is detected
- cd0 is detected (cd0 at atapibus0 drive 1: <QEMU DVD-ROM, QM00004, 2.5+> 
cdrom removable)
- no PVH devices are detected
- boot device is <unknown>, so drops to root device: prompt
- entering cd0a at root device: prompt (and accepting defaults for 
dump device, filesystem and init path) allows the installer to start
- a standard GPT install is succesful and the machine will boot

After the install, you can get the VM's UUID (from either XenCenter or 
by using xe vm-list name-label="VMNAME") and switch viridian to false:

xe vm-param-set uuid=VMUUID platform:viridian=false

With viridian=false:
- detects xennet0, not wm0
- detects xbd0, not ld0 at nvme0
- neither cd0 or xbd1 are detected (*)
- inserting an ISO image does nothing (on a PV VM a new xbd1 device would 
be created)
- spurious wd0 device aappears spamming the dmesg with errors. I suspect 
this is probably down to attempting wedge autodiscovery
wd0 at atabus0 drive0
wd0: <ST506>
wd0: 69632 KB, 1024 cyl, 8 head, 17 sec, 512 byte/sect x 139264 sectors
wd0d: error reading fsbn 0 (wd0 nb 0; cn 0 tn 0 sn 0), xfer 30, retry 0
wd0: (aborted command)
- userconf=disable wd in /boot.cfg stops the above

Both viridian modes give warnings such as:
WARNING: NVRAM century is XX but RTC year is 2023
(where XX is a changing two-digit number)

Because of (*) above, you cannot install with viridian=false as the ISO 
image is not accessible, so you get dropped to a root device: prompt with 
no useful device options.

It is also not possible to boot an alternative kernel (such as 
netbsd-INSTALL.gz) as the boot loader appears unable to read anything 
except for files in the root of the ISO:

> ls
: Not a directory
> boot /and64/binary/kernel/netbsd-INSTALL.gz
boot: cd0a:/and64/binary/kernel/netbsd-INSTALL.gz: No such file or 
directory

--
Stephen