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Re: [Xen-devel] Serial console problem with Xen 3.0

To: "Michael Paesold" <mpaesold@xxxxxx>
Subject: Re: [Xen-devel] Serial console problem with Xen 3.0
From: "Amitayu Das" <amitayudas@xxxxxxxxx>
Date: Fri, 7 Apr 2006 10:47:56 -0400
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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I finally got it working. Let me mention the steps below. Please point out if I'm doing something wrong or weird:

1. We need to config the kernel to support this functionality and recompile krenel for this. In order to do that, follow these steps:

a. go to xen root directory
b. go to linux-2.6.12-xen0
c. make ARCH=xen menuconfig
d. enable options for
   Device Driver --> Character Device -->Serial Drivers

Enable appropriate options and save the new configrations.
e. recompile the kernel and install the new kernel.
f. Put the following entries into the /etc/grub.conf:

serial --unit=0 --speed=9600 --word=8 --parity=no --stop=1
terminal --timeout=10 serial console

title Ourxen (Mar 17-xen0)
        root (hd0,0)
        kernel /xen.gz dom0_mem=131072
        module /vmlinuz- ro root=LABEL=/ rhgb quiet console=tty0  console=ttyS0,9600n8
        module /initrd-
g. reboot the machine with the new image

Currently, this is working for me. If someone can tell me a better way to do the things, that'd be great !!


On 4/7/06, Michael Paesold <mpaesold@xxxxxx> wrote:
Stephen C. Tweedie wrote:
> On Wed, 2006-04-05 at 00:40 -0400, Amitayu Das wrote:
>> 1. I can boot normal Linux FC4 kernel and direct its output to serial
>> console (and see the messages in a separate monitor) using the options
>> as mentioned in the grub.conf.
>>     If I do the exactly the same (meaning, whatever you can see as
>> uncommeted lines in the xen-related portion of the grub.conf),
>>     I can't see the messages in the separate monitor.
> Right, because you commented out the xen.gz com1=... line, so there's no
> HV serial console.  You need that enabled.
>> 2. If I uncomment the third line in the following:
>> #       kernel /xen.gz dom0_mem=131072 com1=9600,8n1
>> then Xen even does not boot up.
> I've seen this a lot --- for me, adding "sync_console" to that xen.gz
> line cures it.  Does that help for you?

Me too. Adding "sync_console" at least repaired the console *output*. I
still have the problem that keyboard input does not reach linux, as it
seems. Here is my config:

serial --unit=0 --speed=38400 --word=8 --parity=no --stop=1
terminal --timeout=10 serial console
title CentOS ( 2.6.16-2.EL4xen0)
        root (hd0,0)
        kernel /xen.gz-2.6.16-2.EL4 com1=38400,8n1 conswitch=s sync_console
        module /vmlinuz-2.6.16-2.EL4xen0 ro root=LABEL=/1 console=tty0
        module /initrd-2.6.16-2.EL4xen0.img

Using the same config for native linux gives me a working console access
(NB. I have agetty in inittab). In Xen/Linux I get all boot messages (from
linux and Xen), but when I hit the login prompt, no keyboard input is
excepted. I am using minicom on the other side of the cable.

Additionally, pressing CTRL-A (or CTRL-S after changing the key) three times
does *not* give me access to the Xen console.

Any additional hints how I could get this working? (NB. this is
xen-unstable, just a two days old, on x86 with an Intel 7210 board).

Best Regards,
Michael Paesold

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