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

[Jan Kiszka]

On 2011-10-07 14:25, Wen Congyang wrote:
> 于 2011/10/7 18:16, Jan Kiszka 写道:
>> On 2011-10-07 11:46, Wen Congyang wrote:
>>> Currently, virsh dump uses monitor command migrate to dump guest's memory
>>> to file, and we can use crash to analyze the file.
>>>
>>> Unfortunately, virsh dump can not work if guest uses host pci device. The
>>> reason is that the device's status is also needed to migrate to remote 
>>> machine,
>>> and the host pci device's status is not stored in qemu. So it is 
>>> unmigratable.
>>>
>>> I think we can  we can add a option to qmp command migrate(eg: skip) to 
>>> allow
>>> the user to skip the check, and this option should be used only when dumping
>>> the guest's memory.
>>
>> Why not simply attach gdb? That works independently of migration.
> 
> If qemu has some problem, we can use gdb to debug it. But if guest os 
> has problem
> (eg:kernel panic and kdump does not work), we should dump guest's memory 
> and use
> crash to analyze.

qemu-system-xxx -s (or "gdbserver" via monitor if qemu is already
running), gdb vmlinux, then "target remote :1234".

Jan

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