Re: [PATCH v2 COLOPre 03/13] libxc/restore: zero ioreq page only one time

[Wen Congyang <wency@cn.fujitsu.com>]

On 06/11/2015 09:25 PM, Paul Durrant wrote:
>> -----Original Message-----
>> From: Yang Hongyang [mailto:yanghy@cn.fujitsu.com]
>> Sent: 11 June 2015 13:59
>> To: Paul Durrant; Wen Congyang; Andrew Cooper; xen-devel@lists.xen.org
>> Cc: Wei Liu; Ian Campbell; guijianfeng@cn.fujitsu.com;
>> yunhong.jiang@intel.com; Eddie Dong; rshriram@cs.ubc.ca; Ian Jackson
>> Subject: Re: [Xen-devel] [PATCH v2 COLOPre 03/13] libxc/restore: zero ioreq
>> page only one time
>>
>>
>>
>> On 06/11/2015 06:20 PM, Paul Durrant wrote:
>>>> -----Original Message-----
>>>> From: Wen Congyang [mailto:wency@cn.fujitsu.com]
>>>> Sent: 11 June 2015 09:48
>>>> To: Paul Durrant; Andrew Cooper; Yang Hongyang; xen-
>> devel@lists.xen.org
>>>> Cc: Wei Liu; Ian Campbell; guijianfeng@cn.fujitsu.com;
>> [...]
>>>
>>>>
>>>> In our implementation, we don't start a new emulator. The codes can
>> work,
>>>> but some bugs may be not triggered.
>>>>
>>>
>>> How do you reconcile the incoming QEMU save record with the running
>> emulator state?
>>
>> We introduce a qmp command "xen-load-devices-
>> state"(libxl__qmp_restore) which
>> can restore the emulator state. The step of resotre emulator state at a
>> checkpoint is:
>>
>> 1. libxl__qmp_stop    -> vm_stop() in qemu
>> 2. libxl__qmp_restore -> load_vmstate() in qemu
>> 3. libxl__qmp_resume  -> vm_start() in qemu
>>
> 
> Ok, that sounds like the ideal time to hook back into Xen by creating a new ioreq server.

I have some questions about ioreq server:
1. If we use old version xen and newest version qemu, is it OK? Is default
   ioreq server created when the guest is created. xen_create_ioreq_server() does
   nothing, and xen_get_ioreq_server_info() will get the default ioreq server information.
   Is it right?
2. Why we create a default ioreq server when getting the hvm param if there is already a
   not default ioreq server?
3. In the far end, we will clear the ioreq page, and this ioreq page is used for default
   ioreq server, is it right?

Thanks
Wen Congyang

> 
>   Paul
> 
>>>
>>>    Paul
>>>
>>>> Thanks
>>>> Wen Congyang
>>>>
>>>>>
>>>>>    Paul
>>>>>
>>>>>>
>>>>>> Thanks
>>>>>> Wen Congyang
>>>>>>
>>>>>>>
>>>>>>>    Paul
>>>>>>>
>>>>>>>> We will set to the guest to a new state, the old state should be
>>>> dropped.
>>>>>>>>
>>>>>>>> Thanks
>>>>>>>> Wen Congyang
>>>>>>>>
>>>>>>>>>
>>>>>>>>>    Paul
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Thanks
>>>>>>>>>> Wen Congyang
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>    Paul
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>> Thanks
>>>>>>>>>>>> Wen Congyang
>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> ~Andrew
>>>>>>>>>>>>> .
>>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> .
>>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> .
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> Xen-devel mailing list
>>>>>>>> Xen-devel@lists.xen.org
>>>>>>>> http://lists.xen.org/xen-devel
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Xen-devel mailing list
>>>>>>> Xen-devel@lists.xen.org
>>>>>>> http://lists.xen.org/xen-devel
>>>>>>> .
>>>>>>>
>>>>>
>>>>> .
>>>>>
>>>
>>>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@lists.xen.org
>>> http://lists.xen.org/xen-devel
>>> .
>>>
>>
>> --
>> Thanks,
>> Yang.
> .
>