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

[Wen Congyang]

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.

> 
>> 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.

Thanks
Wen Congyang

> 
> Thanks.
> HATAYAMA, Daisuke
> 
>