Re: VM not booting anymore after Ubuntu upgrade

["André Weidemann" <Andre.Weidemann@web.de>]

On 04.08.2010 12:31, Avi Kivity wrote:
> On 08/04/2010 10:38 AM, André Weidemann wrote:
>>
>>> Please enable ftrace:
>>>
>>> # mount -t debugfs debugfs /sys/kernel/debug
>>> # cd /sys/kernel/debug/tracing
>>> # echo 100000 > buffer_size_kb
>>> # echo kvm > set_event
>>> # echo 1 > tracing on
>>>
>>> run the guest and kill qemu immediately when you get to the blank screen
>>> (use SDL so you can see it immediately). Then post
>>> /sys/kernel/debug/trace somewhere.
>>
>> I ran the trace and put the ouptut here:
>> http://ilpss8.dyndns.org/~andrew/qemu-kvm.trace.gz
>>
>
>
> <...>-26008 [001] 5175193.046430: kvm_exit: reason exception rip 0xfc842
> <...>-26008 [001] 5175193.046430: kvm_page_fault: address fc842
> error_code 9
> <...>-26008 [001] 5175193.046432: kvm_entry: vcpu 0
> <...>-26008 [001] 5175193.046434: kvm_exit: reason cr_access rip 0xfc796
> <...>-26008 [001] 5175193.046435: kvm_cr: cr_write 0 = 0x10
> <...>-26008 [001] 5175193.046442: kvm_entry: vcpu 0
> <...>-26008 [001] 5175193.046444: kvm_exit: reason exception rip 0xfc799
> <...>-26008 [001] 5175193.046447: kvm_entry: vcpu 0
> <...>-26008 [001] 5175193.046449: kvm_exit: reason exception rip 0xfc799
> <...>-26008 [001] 5175193.046449: kvm_page_fault: address feffd066
> error_code 9
> <...>-26008 [001] 5175193.046453: kvm_inj_virq: irq 13
>
> #GP at fc799.
>
> fc78f: 0f 20 c0 mov %cr0,%eax
> fc792: 66 83 e0 fe and $0xfffffffe,%eax
> fc796: 0f 22 c0 mov %eax,%cr0
> fc799: ea 9e c7 00 f0 ljmp $0xf000,$0xc79e
>
> I think we're in big real mode and your kernel has trouble emulating the
> ljmp. Can you try latest seabios[1]? Commit 0f788893a8bba has a workaround.
>
>
> [1] git://git.linuxtogo.org/home/kevin/seabios.git

Thank you very much. Running qemu-kvm with the latest seabios fixed the 
problem. The VM is running fine again.

Best Regards
  André