RE: [PATCH] vhost: fix virtio blk vDPA live migration IO drop

["Pei, Andy" <andy.pei@intel.com>]

HI Maxime,

Thanks.

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Friday, July 1, 2022 9:55 PM
> To: Pei, Andy <andy.pei@intel.com>; dev@dpdk.org
> Cc: Xia, Chenbo <chenbo.xia@intel.com>; Xu, Rosen <rosen.xu@intel.com>;
> Xiao, QimaiX <qimaix.xiao@intel.com>
> Subject: Re: [PATCH] vhost: fix virtio blk vDPA live migration IO drop
> 
> 
> 
> On 6/22/22 09:47, Andy Pei wrote:
> > In the virtio blk vDPA live migration use case, before the live
> > migration process, QEMU will set call fd to vDPA back-end. QEMU and
> > vDPA back-end stand by until live migration starts.
> > During live migration process, QEMU sets kick fd and a new call fd.
> > However, after the kick fd is set to the vDPA back-end, the vDPA
> > back-end configures device and data path starts. The new call fd will
> > cause some kind of "re-configuration", this kind of "re-configuration"
> > cause IO drop.
> > After this patch, vDPA back-end configures device after kick fd and
> > call fd are well set and make sure no IO drops.
> > This patch only impact virtio blk vDPA device and does not impact net
> > device.
> >
> > Fixes: 7015b6577178 ("vdpa/ifc: add block device SW live-migration")
> >
> > Signed-off-by: Andy Pei <andy.pei@intel.com>
> > ---
> >   lib/vhost/vhost_user.c | 15 +++++++++++++++
> >   1 file changed, 15 insertions(+)
> >
> 
> Applied to dpdk-next-virtio/main.
> 
> Thanks,
> Maxime