Booting NetBSD in pygrub

["M. Boerschig" <code+mlist@boerschig.net>]

Hi,

I'm working on NetBSD support in pygrub: I've posted my work on the
NetBSD port-xen list [1].  It adds support for FFSv2 to tools/libfsimage
and NetBSD partition/disklabel support to tools/pygrub.
I started off using xen-unstable and the xl tools on a kernel 3.2, but
I'm now on xen-4.3 and kernel 3.10.

Retrieving the kernel and arguments appears to work, but the boot
process waits for a console escape character before continuing:

 dom0# pygrub --debug --output-directory=/tmp /dev/mapper/vg00-ffsv2
 linux (kernel /tmp/boot_kernel.NR37Lm)(args "root=xbd0 ")
 dom0# md5sum /tmp/boot_kernel.NR37Lm
 9e492b31e18f7e816f3e374d7f365857  /tmp/boot_kernel.NR37Lm
 dom0# $XEN/tools/xcutils/readnotes /tmp/boot_kernel.NR37Lm
 __xen_guest: GUEST_OS=NetBSD,GUEST_VER=4.99,XEN_VER=xen-3.0,LOADER=generic,
 VIRT_BASE=0xffffffff80000000,ELF_PADDR_OFFSET=0xffffffff80000000,
 VIRT_ENTRY=0xffffffff80100000,HYPERCALL_PAGE=0x00000101,BSD_SYMTAB=yes

 dom0# xl create -c ffsv2/config
 Parsing config from ffsv2/config
 #XXX here it hangs in a xenconsole until a Control-] is enterted
 ^]
 Daemon running with PID 3635
 Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
     2006, 2007, 2008, 2009, 2010, 2011, 2012
     The NetBSD Foundation, Inc.  All rights reserved.
 Copyright (c) 1982, 1986, 1989, 1991, 1993
     The Regents of the University of California.  All rights reserved.

 NetBSD 6.1 (XEN3_DOMU)
 total memory = 512 MB
 avail memory = 487 MB
 mainbus0 (root)
 hypervisor0 at mainbus0: Xen version 4.3.1-pre
 [... snip]
 boot device: xbd0
 root on xbd0a dumps on xbd0b
 Your machine does not initialize mem_clusters; sparse_dumps disabled
 root file system type: ffs
 /etc/rc.conf is not configured.  Multiuser boot aborted.
 Enter pathname of shell or RETURN for /bin/sh: /bin/ksh
 # md5 /netbsd
 MD5 (/netbsd) = 9e492b31e18f7e816f3e374d7f365857

I've tracked this issue down to the boot hanging in a xenconsole:
xenconsoled creates a xenconsole which basically does nothing.
The boot continues with a new xenconsole after sending a control-].
I experimented with different boot arguments like "console=hvc0
xencons=tty" to no avail.

I'm really clueless about what's wrong.
Any help appreciated.

[1] http://mail-index.netbsd.org/port-xen/2013/09/02/msg008020.html