Question about vDPA support for live migration

Sean Mooney smooney at
Thu Sep 9 11:25:21 UTC 2021

On Thu, 2021-09-09 at 15:47 +0800, Jeffrey Zhang wrote:
> Hey everyone,
> I am testing vDPA on OpenStack Wallaby. I have set it up successfully. But
> I found there are several features that are not implemented, including
> live/code migration[0], which I wanted.
> Anyone know what's the latest progress about this. when will the live
> migration feature land?
> I found no talk about this.
high i had planned on anding some more feature in xena but i was not able to work on it this cycle

live migration is not a feature we can enable currently as qemu does not support it so it will likely be the Z or A
cycle before live migration will be supported.

currently we really only support boot, start/stop/reboot (hard and soft)/rebuild and vm delete in termes of lifecycle events.

i had hoped to add shelve, evacuate, resize and cold migration in xena but i will try to find time to work on it in yoga instead.
resize to same host works but we blocked it sicne resize to different host was untested.
shelve works but unshelve failed and i did not have time to understand why during wallaby
suspend fails because i have not extended it to unplug the vdpa devices like pci devices and libvirt managed_save requires that.
if resize to different host works cold migrate will too they go hand in hand.
evacuate is just rebuild to adifferent host i suspect it will mostly work but like cold migrate it was untested and we will need to ensure the
devices are claimed correctly. interface attach works but it blocked because qemu raised an error if we tried to detach
im hopintg that with a newer version of qemu this will just work.

there are todos in the code that note most of this if you or other have time to work on this then please do.
i currently have issue getting the hardware to work on this deploy as a result its not easy for me to work on this currently.

while i do have 2 phsyical nics that support vdpa the servier i intended to use fot finsih this work are too old
to be able to boot with them installed. i dont have access to the server i used for the inital developemt as that was
a loan that is normaly used for ci and QE testing so i dont really have an option of uing it for protracted period of time
to do developement.

> [0]
> <>
> <>
> releasenotes/notes/vdpa-cc2300d2c46c150b.yaml
> Thanks.

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