Re: [Qemu-devel] [RFC] dump memory when host pci device is used by guest

[Sergio Durigan Junior <sergiodj@redhat.com>]

Jan Kiszka <jan.kiszka@web.de> writes:

> On 2011-11-21 06:06, Wen Congyang wrote:
>> At 11/18/2011 08:46 PM, Jan Kiszka Write:
>>> On 2011-11-16 14:29, Dave Anderson wrote:
>>>>
>>>>
>>>> ----- Original Message -----
>>>>> Hi, all
>>>>>
>>>>> 'virsh dump' can not work when host pci device is used by guest. We have
>>>>> discussed this issue here:
>>>>> http://lists.nongnu.org/archive/html/qemu-devel/2011-10/msg00736.html>>>>
>>>>> We have determined to introduce a new command dump to dump memory.
>>>>> The core file's format can be elf.
>>>>>
>>>>> I created a kdump-elf vmcore, and found that it can be used by both
>>>>> crash and gdb:
>>>>>
>> 
>>>> From an enterprise/support point of view, the wholesale replacement
>>>> of the current use of the savevm dumpfile format by "virsh dump" with
>>>> this ELF style format would be a *huge* improvement. 
>>>
>>> Yes, fully agree. Would be cool if that could actually work for both
>>> crash and gdb. Looking forward!
>> 
>> Because the memory size for x86 machine can greater than 4G, so we should
>> create elf64 format core file for 32bit OS.
>> 
>> I create a vmcore: the guest OS is 32-bit, and the vmcore is elf64 format.
>> I can use crash to anaylyze it, but gdb can not do the same thing.
>> 
>> I create a kdump-elf64 vmcore on 32-bit machine, and gdb still can not anaylyze
>> it.
>> 
>> Does gdb support elf64 format core file on x86 box?
>> 
>
> Dunno, but I'm trying to pull in some interested gdb folks.

Hello,

IIRC, GDB supports ELF64 corefiles on x86 boxes, but only when
configured with `--enable-64-bit-bfd'.  Otherwise, it won't be able to
properly understand the format.