Re: Unable to single-step in kvm, always results in a resume

Nicholas Amon
2010-01-22T03:54:32Z

So now I can step instruction but my breakpoints do not work. I have
verified that disabling kvm restores the breakpoint functionality. Any
suggestions?

Thanks,

Nicholas

Jan Kiszka wrote:
> Hi Nicholas,
>
> please don't drop CCs on reply.
>
> Nicholas Amon wrote:
>
>> Hi Jan,
>>
>> Thanks for responding. Yes, I am able to step instruction when I
>> disable kvm w/ the no-kvm option. My host kernel is 64bit 2.6.27 and
>> the program that I am debugging is 32 bit but starts in real mode. But
>> the KVM module I am running is from kvm-88. Is there anyway I can check
>> the version definitively?
>>
>
> kvm modules issue a message when being loaded, check your kernel log.
> qemu-kvm gives you the version via -version.
>
> OK, the problems you see is likely related to the very old versions you
> use. Update to recent kvm-kmod (2.6.32 series) and qemu-kvm (0.12
> series) and retry.
>
> Jan
>
>
>> Thanks,
>>
>> Nicholas
>>
>> Jan Kiszka wrote:
>>
>>> Jan Kiszka wrote:
>>>
>>>
>>>> Nicholas Amon wrote:
>>>>
>>>>
>>>>> Hi All,
>>>>>
>>>>> I am trying to single-step through my kernel using qemu and kvm. I have
>>>>> run qemu via: qemu-system-x86_64 -s -S -hda
>>>>> /home/nickamon/lab1/obj/kernel.img and also connected to the process
>>>>> using gdb.
>>>>>
>>>>> Problem is that whenever I try and step instruction, it seems to resume
>>>>> my kernel rather than allowing me to progress instruction by
>>>>> instruction. I have built the kvm snapshot from git and still no luck.
>>>>> Tried following the code for a few hours and have no luck. Any
>>>>> suggestions?
>>>>>
>>>>>
>>>> What's you host kernel or kvm-kmod version?
>>>>
>>>>
>>>>
>>> ...and does -no-kvm make any difference (except that it's much slower)?
>>>
>>> Jan
>>>
>>>
>>>
>
>

--
Nicholas Amon
Senior Software Engineer
Xceedium Inc.
Office: 201-536-1000 x127
Cell: 732-236-7698
namon@Xceedium.com

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