Re: [Qemu-devel] [RFC][PATCH 00/14 v7] introducing a new, dedicated memory dump mechanism

[Wen Congyang]

At 03/02/2012 08:49 AM, HATAYAMA Daisuke Wrote:
> From: Wen Congyang <address@hidden>
> Subject: Re: [RFC][PATCH 00/14 v7] introducing a new, dedicated memory dump 
> mechanism
> Date: Thu, 01 Mar 2012 13:16:47 +0800
> 
>> At 03/01/2012 12:42 PM, HATAYAMA Daisuke Wrote:
>>> From: Wen Congyang <address@hidden>
>>> Subject: [RFC][PATCH 00/14 v7] introducing a new, dedicated memory dump 
>>> mechanism
>>> Date: Thu, 01 Mar 2012 10:35:44 +0800
>>>
>>>> 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
>>>>
>>>> The last version is here:
>>>> http://lists.nongnu.org/archive/html/qemu-devel/2012-02/msg01007.html
>>>>
>>>> We have determined to introduce a new command dump to dump memory. The core
>>>> file's format can be elf.
>>>>
>>>> Note:
>>>> 1. The guest should be x86 or x86_64. The other arch is not supported now.
>>>> 2. If you use old gdb, gdb may crash. I use gdb-7.3.1, and it does not 
>>>> crash.
>>>
>>> Does this say the thing caused by gdb versions with no Dwarf V3
>>> support? If so, it's better to write that too explicitly here.
>>
>> I donot know why gdb crashed, and I cannot reproduce this problem now.
>>
> 
> Sorry. I meant Dwarf4. Recent GCC emits binary with Dwarf4 in default,
> and older GDBs cannot handle them although I don't know this is the
> same as what you saw.

I guess it is not, as I cannot reproduce this problem.

Thanks
Wen Congyang

> 
>>>> 3. If the OS is in the second kernel, gdb may not work well, and crash can
>>>>    work by specifying '--machdep phys_addr=xxx' in the command line. The
>>>>    reason is that the second kernel will update the page table, and we can
>>>>    not get the page table for the first kernel.
>>>> 4. The cpu's state is stored in QEMU note. You neet to modify crash to use
>>>>    it to calculate phys_base.
>>>
>>> Again, you still need to fix crash utility to recover the 1st kernel's
>>> first 640kB physical memory that has been reserved during switch from
>>> 1st kernel to 2nd kernel.
>>
>> It is another work, I will try to do it in the future.
>>
> 
> Please.
> 
> Thanks.
> HATAYAMA, Daisuke
> 
>