From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
[mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Mike Viau
Sent: Saturday, April 24, 2010 23:50
To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: RE: [Xen-users] Serial console - Xen 4.0 - debugging pv_ops 2.6.31dom0
kernel
> Sat, 24 Apr 2010 17:39:55 -0400
<greno@xxxxxxxxxxx> wrote:
> Matej Zary wrote:
> > Well, it seems, problem is the IO ports Kouwell PCI card - 01:0a.0
Communication controller: NetMos Technology PCI 9835 Multi-I/O Controller (rev
01).
> >
> > COM ports work in standard Lenny kernel like charm, but when I remove
these modules, they caese to work - so it seems they need special driver to
work - so I assume that's the reason they don't work during xen boot process
(or I'm wrong? :) ).
> >
> > lsmod
> >
> > parport_serial 11264 0
> > parport_pc 31016 1 parport_serial
> > parport 41776 1 parport_pc
> >
> >
> > Any ideas? (or advice on proven PCI card with COM ports that are
usable for monitoring xen boot process)?
> >
> >
> > Regards
> >
> > Matej
> >
> >
> > -----Original Message-----
> > From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
[mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Matej Zary
> > Sent: Monday, April 19, 2010 4:57 PM
> > To: xen-users@xxxxxxxxxxxxxxxxxxx
> > Subject: [Xen-users] Serial console - Xen 4.0 - debugging pv_ops
2.6.31 dom0 kernel
> >
> > Hello all,
> >
> > I compiled from source Xen 4.0 with the default 2.6.31.13 pv_ops dom0
kernel on barebone Debian Lenny installation. Problem is, this dom0 kernel
won't boot. First complaining about ioapic, so I tried with noioapci, still no
luck (the screen blackens during boot and computer reboots). :( So here comes
serial console. This PC is older shady Asrock nForce 430 board with AMD Athlon
X2 1,9 Ghz CPU => no onboard serial port. Therefore I added PCI card with
i/o ports.
> >
> > dmesg | grep tty
> > [ 0.004000] console [tty0] enabled
> > [ 0.923873] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
> > [ 0.924008] 00:0a: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
> > [ 7.887891] 0000:01:0a.0: ttyS1 at I/O 0xec00 (irq = 18) is a 16550A
> > [ 7.887891] 0000:01:0a.0: ttyS2 at I/O 0xe480 (irq = 18) is a 16550A
> >
> >
> > According to http://wiki.xensource.com/xenwiki/XenSerialConsole I
used usb->com cable on my laptop and tried the link test with minicom on
both sides - chatting worked flawlessly (using /dev/ttyS1 on "server"
side).
> >
> > Problem is, I'm not able configure boot options for Xen to work with
this serial port. My grub menu.lst (one from many experiments):
> >
> > title Xen 4.0, Linux kernel 2.6.31.13 with serial console
> > root (hd0,0)
> > kernel /boot/xen-4.0.gz dom0_mem=512M loglvl=all guest_loglvl=all
com2=115200, 8n1, 0xec00, 18 console=com2
> > module /boot/vmlinuz-2.6.31.13 root=/dev/sda1 ro console=hvc0
earlyprintk=xen nomodeset
> > module /boot/initrd.img-2.6.31.13
> >
> > Tried many variations, but still no luck getting the xen boot process
on my serial connected console.
> >
> > Any hints?
> >
> >
> > Many thanks.
> >
> > Matej
> >
> >
> Marej,
> I am facing same problem as you. Cannot get pv_ops dom0 kernel to
> boot on my hardware (AMD) and trying to get console output from MB w/o
> serial port. I thought in 2.6.31 kernels there was support for USB
> console? I had seen this somewhere but cannot find it now. Not sure
> how USB console would be configured to other machine. The only way I
> can think to do this is with a USB-RS232 dongle.
>
I hate to be the be the one to give you the bad news but a USB dongle does not
load up in the kernel early enough to capture the Xen hypervisor boot messages.
As far as my understanding goes a USB serial dongle can not even be used to log
the dom0 kernel messages as the usb drivers need to be loaded in memory before
the serial port can be made and this is much latter in the kernel's boot-up.
-M
This stands to reason
regarding a USB->R232 driver, however, does anyone know if most BIOSes “Legacy
USB” support settings apply to RS232 as well, or only to PS/2 and removable
media? I ask because if the “Legacy USB” settings apply to USB->RS232 as
well, then appropriately configuring them in the BIOS would prevent the
hypervisor from knowing the serial port wasn’t a standard physical one (much
like booting to DOS or OS/2 on a thumb drive or external USB hard drive doesn’t
require those operating systems to have a USB driver at all).
Dustin
