Re: [Qemu-devel] [PATCH v3 0/5] Add migration support for VFIO device

[Neo Jia <cjia@nvidia.com>]

On Thu, Feb 21, 2019 at 05:52:53AM +0000, Tian, Kevin wrote:
> > From: Kirti Wankhede [mailto:kwankhede@nvidia.com]
> > Sent: Thursday, February 21, 2019 1:25 PM
> > 
> > On 2/20/2019 3:52 PM, Dr. David Alan Gilbert wrote:
> > > * Kirti Wankhede (kwankhede@nvidia.com) wrote:
> > >> Add migration support for VFIO device
> > >
> > > Hi Kirti,
> > >   Can you explain how this compares and works with Yan Zhao's
> > > set?
> > 
> > This patch set is incremental version of my previous patch set:
> > https://patchwork.ozlabs.org/cover/1000719/
> > This takes care of the feedbacks received on previous version.
> > 
> > This patch set is different than Yan Zhao's set.
> > 
> 
> I can help give some background about Yan's work:
> 
> There was a big gap between Kirti's last version and the overall review
> comments, especially this one:
> https://www.mail-archive.com/qemu-devel@nongnu.org/msg576652.html

Hi Kevin,

> 
> Then there was no reply from Kirti whether she agreed with the comments
> and was working on a new version.

Sorry, we should ack on those comments when we have received them last time.

> 
> Then we think we should jump in to keep the ball moving, based on
> a fresh implementation according to recommended direction, i.e. focusing
> on device state management instead of sticking to migration flow in kernel
> API design.
> 
> and also more importantly we provided kernel side implementation based
> on Intel GVT-g to give the whole picture of both user/kernel side changes.
> That should give people a better understanding of how those new APIs
> are expected to be used by Qemu, and to be implemented by vendor driver.
> 
> That is why Yan just shared her work.

Really glad to see the v2 version works for you guys, appreciate for the driver
side changes.

> 
> Now it's great to see that Kirti is still actively working on this effort and is
> also moving toward the right direction. Let's have a close look at two
> implementations and then choose a cleaner one as base for future
> enhancements. :-)

Yes, the v3 has addressed all the comments / concerns raised in the v2, I think
we should take a look and keep moving.

Just a quick thought - would be possible / better to have Kirti focus on the QEMU 
patches and Yan take care GVT-g kernel driver side changes? This will give us
the best testing coverage. Hope I don't step on anybody's toes here. ;-)

Thanks,
Neo

> 
> Thanks
> Kevin