[Crash-utility] Re: [PATCH 1/2] Add x86_64 linux-2.6.27 support: Catch up the PAGE_OFFSET change.

[Ken'ichi Ohmichi]

Hello Dave,

Dave Anderson wrote:
>> I think that a new virtualization_init() function is a good idea.
>>
>> How about checking whether "Xen" exists in PT_NOTE section of an vmcore
>> at virtualization_init()? I feel that it is safer than reading a xen_start_info
>> pointer.
>>
>> $ readelf -n vmcore
>> Notes at offset 0x00000120 with length 0x00001388:
>>   Owner         Data size       Description
>>   CORE          0x00000150      NT_PRSTATUS (prstatus structure)
>>   Xen           0x00000020      Unknown note type: (0x01000002)  <----- HERE
>>   CORE          0x00000150      NT_PRSTATUS (prstatus structure)
>>   Xen           0x00000020      Unknown note type: (0x01000002)  <----- HERE
>>   Xen           0x00000050      Unknown note type: (0x01000001)  <----- HERE
>>   VMCOREINFO_XEN                0x00000fe4      Unknown note type: (0x00000000)
>> $
> 
> Well there may be a couple issues with that approach.  First, we need
> a way to handle/recognize it on live systems. And second, I believe we'll need
> a way to differentiate a pv_ops/xen kernel from a "dedicated" xen kernel.
> And my guess is that the vmcore notes will not differentiate between the
> two "flavors" of xen kernel (unless there's an entry in the VMCOREINFO_XEN
> that will somehow differentiate the two).

Thank you for the good comment. I understand your plan, and I think it is
better than mine.


Thanks
Ken'ichi Ohmichi