xen discuss - May 2008 - Switching serial console between dom0 and Xen

I installed OpenSolaris from SXDE 1/08 (build 79a), which also includes Solaris
xVM. I configured Xen to output its messages to the serial console, as described
here: http://www.opensolaris.org/os/community/xen/docs/serial-console/. When I
booted xVM, everything worked as expected: I was able to see Xen messages on the
serial console and I was also able to switch the console between Xen and dom0
(by pressing Ctrl-a three times), and saw console messages from dom0.

Then I downloaded Xen source from the build 79 on-gate:
http://dlc.sun.com/osol/on/downloads/b79/. I built a new xen.gz image and copied
it on the machine where I run Solaris xVM. Then I booted the newly compiled
xen.gz image, and found that although I was still able to switch the console
between Xen and dom0, I was not getting any output from dom0 (I did get the
output from Xen). I did not change the dom0 guest. It was the guest that comes
with SXDE 1/08 (b79) and that was able to print to serial console when the
xen.gz from SXDE 1/08 was loaded. All I did was recompile xen.gz, and now dom0
can''t output to serial console.

Any idea what could be the reason?
 
 
This message posted from opensolaris.org

Alexandra (Sasha) Fedorova wrote:
> I installed OpenSolaris from SXDE 1/08 (build 79a),
> which also includes Solaris xVM. I configured Xen to
> output its messages to the serial console, as
> described here:
> http://www.opensolaris.org/os/community/xen/docs/serial-console/.
> When I booted xVM, everything worked as
> expected: I was able to see Xen messages on the
> serial console and I was also able to switch the
> console between Xen and dom0 (by pressing Ctrl-a
> three times), and saw console messages from dom0. 
> 
> Then I downloaded Xen source from the build 79
> on-gate: http://dlc.sun.com/osol/on/downloads/b79/. I
> built a new xen.gz image and copied it on the machine
> where I run Solaris xVM. Then I booted the newly
> compiled xen.gz image, and found that although I was
> still able to switch the console between Xen and
> dom0, I was not getting any output from dom0 (I did
> get the output from Xen). I did not change the dom0
> guest. It was the guest that comes with SXDE 1/08
> (b79) and that was able to print to serial console
> when the xen.gz from SXDE 1/08 was loaded. All I did
> was recompile xen.gz, and now dom0 can''t output to
> serial console. 
> 
> Any idea what could be the reason?
I''m using option "-B console=ttya" on the unix line in 
the /boot/grub/menu.lst file to send dom0 console output
to the serial console.

Like this (But in this exsample I''m using com2 / ttyb):

    title Solaris xVM, Console ttyb
    kernel$ /boot/$ISADIR/xen.gz com2=9600,8n1 console=com2
    module$ /platform/i86xpv/kernel/$ISADIR/unix
/platform/i86xpv/kernel/$ISADIR/unix -B console=ttyb -kv
    module$ /platform/i86pc/$ISADIR/boot_archive
 
 
This message posted from opensolaris.org

On Tue, May 20, 2008 at 04:08:21AM -0700, Jürgen Keil
wrote:
> Alexandra (Sasha) Fedorova wrote:
>
> > I installed OpenSolaris from SXDE 1/08 (build 79a),
> > which also includes Solaris xVM. I configured Xen to
> > output its messages to the serial console, as
> > described here:
> > http://www.opensolaris.org/os/community/xen/docs/serial-console/.
> > When I booted xVM, everything worked as
> > expected: I was able to see Xen messages on the
> > serial console and I was also able to switch the
> > console between Xen and dom0 (by pressing Ctrl-a
> > three times), and saw console messages from dom0.
> >
> > Then I downloaded Xen source from the build 79
> > on-gate: http://dlc.sun.com/osol/on/downloads/b79/. I
> > built a new xen.gz image and copied it on the machine
> > where I run Solaris xVM. Then I booted the newly
> > compiled xen.gz image, and found that although I was
> > still able to switch the console between Xen and
> > dom0, I was not getting any output from dom0 (I did
> > get the output from Xen). I did not change the dom0
> > guest. It was the guest that comes with SXDE 1/08
> > (b79) and that was able to print to serial console
> > when the xen.gz from SXDE 1/08 was loaded. All I did
> > was recompile xen.gz, and now dom0 can''t output to
> > serial console.
> >
> > Any idea what could be the reason?
>
> I''m using option "-B console=ttya" on the unix line in
> the /boot/grub/menu.lst file to send dom0 console output
> to the serial console.
>
> Like this (But in this exsample I''m using com2 / ttyb):
>
>     title Solaris xVM, Console ttyb
>     kernel$ /boot/$ISADIR/xen.gz com2=9600,8n1 console=com2
>     module$ /platform/i86xpv/kernel/$ISADIR/unix
/platform/i86xpv/kernel/$ISADIR/unix -B console=ttyb -kv
>     module$ /platform/i86pc/$ISADIR/boot_archive
>
actually, in the scenario above the "-B console=ttyb" option to unix
is
unnecessary.  by default, solaris detects what xen is using for it''s
console
device and uses the same thing.  (you can of course override that with the
-B or an entry in bootenv.rc, if you want the consoles to go to
different devices.)

ed

I got it working. My problem was that I didn''t build Xen properly the
first time, so that was probably why the switching back and forth did not work.
After I performed the build properly, everything started working.
 
 
This message posted from opensolaris.org

Edward Pilatowicz wrote:
> On Tue, May 20, 2008 at 04:08:21AM -0700, Jürgen Keil wrote:
> >     title Solaris xVM, Console ttyb
> >     kernel$ /boot/$ISADIR/xen.gz com2=9600,8n1 console=com2
> >     module$
/platform/i86xpv/kernel/$ISADIR/unix/platform/i86xpv/kernel/$ISADIR/unix -B
console=ttyb -kv
> >     module$ /platform/i86pc/$ISADIR/boot_archive
> 
> actually, in the scenario above the "-B console=ttyb" option to
unix is
> unnecessary.  by default, solaris detects what xen is using for it's
console
> device and uses the same thing.  (you can of course override that with the
> -B or an entry in bootenv.rc, if you want the consoles to go to
> different devices.)
Hmm, no, I can't omit the -B console=ttyb open when the
hypervisor has it's output redirected to the com2 port;  otherwise
I get hypervisor console output on the serial line, and solaris dom0
console messages on the VGA card (that is, exactly the problem
Alexandra was complaining about).

I have SXCE snv_85 installed, and bfu'ed that multiple times.
In /boot/solaris/bootenv.rc I find this line:

    setprop console 'text'


I seems the snv_85 installer has defined that console
property; my old (more or less unmodified) snv_85 UFS
root already has it defined.
 
 
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Jürgen Keil wrote:
> Edward Pilatowicz wrote:
>> On Tue, May 20, 2008 at 04:08:21AM -0700, Jürgen Keil wrote:
> 
>>>     title Solaris xVM, Console ttyb
>>>     kernel$ /boot/$ISADIR/xen.gz com2=9600,8n1 console=com2
>>>     module$
/platform/i86xpv/kernel/$ISADIR/unix/platform/i86xpv/kernel/$ISADIR/unix -B
console=ttyb -kv
>>>     module$ /platform/i86pc/$ISADIR/boot_archive
>> actually, in the scenario above the "-B console=ttyb" option
to unix is
>> unnecessary.  by default, solaris detects what xen is using for
it's console
>> device and uses the same thing.  (you can of course override that with
the
>> -B or an entry in bootenv.rc, if you want the consoles to go to
>> different devices.)
> 
> Hmm, no, I can't omit the -B console=ttyb open when the
> hypervisor has it's output redirected to the com2 port;  otherwise
> I get hypervisor console output on the serial line, and solaris dom0
> console messages on the VGA card (that is, exactly the problem
> Alexandra was complaining about).
I think "-B console=hypervisor" on the unix line is the right thing to
do if you've set a console for xen.

-Ryan
> 
> I have SXCE snv_85 installed, and bfu'ed that multiple times.
> In /boot/solaris/bootenv.rc I find this line:
> 
>     setprop console 'text'
> 
> 
> I seems the snv_85 installer has defined that console
> property; my old (more or less unmodified) snv_85 UFS
> root already has it defined.
>  
>  
> This message posted from opensolaris.org
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Hi Jurgen, 

If you include the following line in your /boot/solaris/bootenv.rc

setprop console ttyb

then you can omit the -B console=ttyb option. At least this is what I am doing,
and I have no trouble switching between Xen and dom0 on the serial console
anymore.
 
 
This message posted from opensolaris.org