[dpdk-dev] [PATCH 0/4 for 2.3] vhost-user live migration support

Pavel Fedin p.fedin at samsung.com
Wed Dec 16 08:05:31 CET 2015


 Hello!

> 1. if vhost-user backend (or say, DPDK) supports GUEST_ANNOUNCE, and
>    send another RARP (or say, GARP, I will use RARP as example),
>    then there will be two RARP later on the line, right? (since the
>    QEMU one is sent unconditionally from qemu_announce_self).

 qemu_announce_self() is NOT unconditional. It applies only to emulated physical NICs and bypasses virtio/vhost. So it will not send anything at all for vhost-user.

> 2. if the only thing vhost-user backend is to send another same RARP
>    when got SEND_RARP request, why would it bother if QEMU will
>    unconditionally send one?

 See above, it won't send one.
 It looks to me like qemu_announce_self() is just a poor man's solution which even doesn't always work (because GARP should reassociate an existing IP with new MAC, shouldn't it? and qemu doesn't know the IP and just sets both src and dst to 0.0.0.0).

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia




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