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

[Maxime Coquelin <maxime.coquelin@redhat.com>]

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(+)
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime