Re: [Qemu-devel] [PATCH COLO-Frame v10 35/38] netfilter: Introduce a API to automatically add filter-buffer for each netdev

[Wen Congyang]

On 11/05/2015 05:21 PM, Jason Wang wrote:
> 
> 
> On 11/05/2015 04:52 PM, Wen Congyang wrote:
>> On 11/05/2015 03:43 PM, zhanghailiang wrote:
>>>> Hi Jason,
>>>>
>>>> On 2015/11/4 10:56, Jason Wang wrote:
>>>>>>
>>>>>>
>>>>>> On 11/03/2015 07:56 PM, zhanghailiang wrote:
>>>>>>>> Signed-off-by: zhanghailiang <address@hidden>
>>>>>>>> Cc: Jason Wang <address@hidden>
>>>>>>
>>>>>> Commit log please.
>>>>>>
>>>>>>>> ---
>>>>>>>> v10: new patch
>>>>>>>> ---
> 
> [...]
> 
>>>>>>>> +}
>>>>>>>> +/*
>>>>>>>> +* This will be used by COLO or MC FT, for which they will need
>>>>>>>> +* to buffer all the packets of all VM's net devices, Here we check
>>>>>>>> +* and automatically add netfilter for netdev that doesn't attach any 
>>>>>>>> buffer
>>>>>>>> +* netfilter.
>>>>>>>> +*/
>>>>>>>> +void qemu_auto_add_filter_buffer(NetFilterDirection direction, Error 
>>>>>>>> **errp)
>>>>>>>> +{
>>>>>>>> +    char *queue = g_strdup(NetFilterDirection_lookup[direction]);
>>>>>>>> +
>>>>>>>> +    qemu_foreach_netdev(netdev_add_filter_buffer, queue,
>>>>>>>> +                                        errp);
>>>>>>>> +    g_free(queue);
>>>>>>>> +}
>>>>>>>> +
>>>>>>
>>>>>> This make me think for following questions:
>>>>>>
>>>>>> - What if a nic is hot added after this "automatically" filter add?
>> IIRC, we don't allow the user to hotplug a device when colo is running.
>>
>> Thanks
>> Wen Congyang
>>
> 
> Even in the future? And how could forbid the user to do this, management?

If we allow the user to hotplug a device, we need to auto hotplug the same 
device
in the secondary qemu. It is hard to implement it now.

We can add a new flag(for example: MONITOR_CMD_COLO_UNSUPPORTED), and do the 
check
in handle_user_command() and handle_qmp_command().

Thanks
Wen Congyang

> 
> Thanks
> .
>