[PATCH] incompatibility of netfront driver with bonding module

[Yosuke Iwamatsu <y-iwamatsu@ab.jp.nec.com>]

Masroor Vettuparambil wrote:
> Yes, I could do a live migration of pass-through domain using bonding.  

That's great!

Thanks,
   Yosuke

> -----Original Message-----
> From: Yosuke Iwamatsu [mailto:y-iwamatsu@ab.jp.nec.com] 
> Sent: Thursday, April 10, 2008 5:35 PM
> To: Masroor Vettuparambil
> Cc: xen-devel@lists.xensource.com
> Subject: Re: [PATCH] incompatibility of netfront driver with bonding
> module
> 
> Thank you.
> 
> Now I'm curious if you really succeeded the live migration of
> passthrough domains, using pci-hotplug and bonding.
> (Currently I have one testing machine and can only try local migration.)
> 
> -- Yosuke
> 
> Masroor Vettuparambil wrote:
>> The attached patch provides the arp link monitoring support for 
>> netfront.
>> Also it prevents setting the mac while the interface is up.
>>
>> Regards
>> Masroor
>>
>> -----Original Message-----
>> From: Yosuke Iwamatsu [mailto:y-iwamatsu@ab.jp.nec.com]
>> Sent: Monday, April 07, 2008 12:36 PM
>> To: Masroor Vettuparambil
>> Cc: xen-devel@lists.xensource.com
>> Subject: incompatibility of netfront driver with bonding module
>>
>> Masroor Vettuparambil wrote:
>>> Thanks for your work.
>>> I could manage the live migration using a simple check in netfront 
>>> while resuming on destination.
>>>
>>> if (!(netdev->flags & IFF_SLAVE))
>>> 	memcpy(netdev->dev_addr, info->mac, ETH_ALEN); But this will
>> work
>>> only if the interface is enslaved.
>>>
>>> In your patch, should we let to change the MAC while interface is up?
>> It might be desirable, but I don't know for now if we can achieve it 
>> easily.
>>
>>> I need to include the support for arp link monitoring to netfront.
>> Is link monitoring really necessary?
>> If you mean you use link monitoring to change the active slave of the 
>> bond0, I think we can do that using ifenslave command inside domU.
>>   #ifenslave bond0 eth1     -> enslave new netif(eth1) to bonding
> device
>>   #ifenslave -d bond0 eth0  -> release old netif(eth0) from bonding
>>
>> Regards,
>>    Yosuke
>>
>>> Regards
>>> Masroor,
>>>  
>>>
>>> -----Original Message-----
>>> From: Yosuke Iwamatsu [mailto:y-iwamatsu@ab.jp.nec.com]
>>> Sent: Thursday, April 03, 2008 12:00 PM
>>> To: Masroor Vettuparambil
>>> Cc: xen-devel@lists.xensource.com
>>> Subject: incompatibility of netfront driver with bonding module
>>>
>>> Hi,
>>>
>>> Masroor Vettuparambil wrote:
>>>> 1. Normally, bonding will inherit the mac from the first slave and 
>>>> assign it to all the other slaves added later. So the mac of vif 
>>>> will
>>>> be updated. But during migration, the mac of vif is getting updated 
>>>> from xenstore(/vm/). So how about having a set_mac_address entry in 
>>>> netfront that update the xenstore?
>>>> So I need help, especially on #1. Is it ok to update the xenstore 
>>>> /vm/ keys from domU? how to do this?
>>> I tried a bit to find out the way to update /vm/ keys from frontend, 
>>> but didn't succeed. Either way, I don't think it is a good idea to 
>>> update the xenstore key of the vif mac address, because the original 
>>> mac will be lost and we won't be able to reset it e.g. after the 
>>> guest
>> reboot.
>>> So the attached patch adds set mac_address() support to netfront.
>>> It doesn't touch xenstore at all, but just preserves the modified mac
> 
>>> address in netfront_info structure and keeps using it after
> migration.
>>> Thanks,
>>> -----------------------
>>> Yosuke Iwamatsu
>>>          NEC Corporation