Re: [PATCH 0/4 for 2.3] vhost-user live migration support

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

On Fri, Dec 11, 2015 at 11:26:55AM +0300, Pavel Fedin wrote:
>  Hello!
> 
>  I am currently testing this patchset with qemu and have problems.

Hi,

Thanks for testing!
> 
>  The guest migrates correctly, but after the migration it cries in the log:
> 
> Vhost user backend fails to broadcast fake RARP

Yes, because I have enabled it yet on DPDK side, and I was intended to
try it in the v2 patchset, which is likely to be sent out next week.

	--yliu

> 
>  and pinging the (new) host doesn't work. When i migrate it back to the old host, the network resumes working.
> 
>  I have analyzed the code, and this problem happens because we support neither VHOST_USER_PROTOCOL_F_RARP, nor
> VIRTIO_NET_F_GUEST_ANNOUNCE. Since the latter seems to be related only to guest, i simply enabled it in qemu by force, and after
> this the network doesn't work at all.
>  Can anybody help me and explain how the thing works? I expected that gratuitous ARP packets are harmless, but they seem to break
> things somehow. And what was used for testing the implementation?
> 
> Kind regards,
> Pavel Fedin
> Expert Engineer
> Samsung Electronics Research center Russia
> 
>