Porting 2.0.7 to newer linux kernel

Porting 2.0.7 to newer linux kernel

[Michal Ludvig]

Hi there,

I'm trying to port Xen 2.0.7 to a more recent kernels than the last 
supported 2.6.12. Why? Because my server is far far away and I'm not 
going to remotely upgrade Xen 2.0 to Xen 3.0 and then fly over there to 
fix it. And after all it's a good coding excercise ;-)

Anyway, going in small steps, thus doing 2.6.13 first. After half a day 
of work it finally compiles but an attempt to create domain with this 
kernel ends up with "Error: Error creating domain: (0, 'Error')" and the 
domain is still present in xm list:

# xm create -c bobek-x2
Using config file "bobek-x2".
Error: Error creating domain: (0, 'Error')
# xm list
Name              Id  Mem(MB)  CPU  State  Time(s)  Console
Domain-0           0      251    0  r----    145.4
Domain-2           2      128    0  --p--      0.0

Where can I get more info on what goes wrong? Can I run the kernel or 
hypervisor in some verbose or debug mode? So far I only got some info 
from xm log, but not too useful:

[2006-02-28 23:14:35 xend] DEBUG (XendDomainInfo:720) init_domain> 
Created domain=2 name=bobek-x2 memory=128
[2006-02-28 23:14:35 xend] INFO (console:94) Created console id=12 
domain=2 port=9602
[2006-02-28 23:14:36 xend] ERROR (SrvBase:162) op=create: Error creating 
domain: (0, 'Error')
Traceback (most recent call last):
   File "/usr/lib/python2.3/site-packages/xen/xend/server/SrvBase.py", 
line 107, in _perform
     val = op_method(op, req)
   File 
"/usr/lib/python2.3/site-packages/xen/xend/server/SrvDomainDir.py", line 
71, in op_create
     raise XendError("Error creating domain: " + str(ex))
XendError: Error creating domain: (0, 'Error')
[2006-02-28 23:14:36 xend] INFO (XendRoot:116) EVENT> 
xend.console.create [12, 2, 9602]
[2006-02-28 23:14:52 xend] INFO (XendRoot:116) EVENT> xend.domain.create 
['Domain-2', '2']

Thanks for any hints!

Michal Ludvig

Re: Porting 2.0.7 to newer linux kernel

[Michal Ludvig]

Michal Ludvig wrote:
> Hi there,
> 
> I'm trying to port Xen 2.0.7 to a more recent kernels than the last 
> supported 2.6.12. Why? Because my server is far far away and I'm not 
> going to remotely upgrade Xen 2.0 to Xen 3.0 and then fly over there to 
> fix it. And after all it's a good coding excercise ;-)
> 
> Anyway, going in small steps, thus doing 2.6.13 first. After half a day 
> of work it finally compiles but an attempt to create domain with this 
> kernel ends up with "Error: Error creating domain: (0, 'Error')" and the 
> domain is still present in xm list:

All right, I got a little bit further. Now the domain gets successfully 
created but the kernel dies immediately:

~# xm create -c bobek-x2
Using config file "/etc/xen/bobek-x2".
Started domain bobek-x2, console on port 9608
************ REMOTE CONSOLE: CTRL-] TO QUIT ********

************ REMOTE CONSOLE EXITED *****************
~#

Could someone advise me where is the very first entry point in the 
kernel that gets executed once the domain is created? Since there is no 
useful content in arch/xen/boot I'm somehow lost as to where the kernel 
starts.

Thanks for any pointers!

Michal

Re: Re: Porting 2.0.7 to newer linux kernel

[Keir Fraser]

On 1 Mar 2006, at 03:01, Michal Ludvig wrote:

> Could someone advise me where is the very first entry point in the 
> kernel that gets executed once the domain is created? Since there is 
> no useful content in arch/xen/boot I'm somehow lost as to where the 
> kernel starts.

The entry point is in arch/xen/kernel/head.S (or maybe 
arch/xen/i386/kernel/head.S).


  -- Keir