RE: [PATCH V4 1/3] net/filter: Remove vnet_hdr from filter-mirror and filter-redirector

[Zhang, Chen]

> -----Original Message-----
> From: Jason Wang <jasowang@redhat.com>
> Sent: Wednesday, October 27, 2021 2:45 PM
> To: Zhang, Chen <chen.zhang@intel.com>
> Cc: qemu-dev <qemu-devel@nongnu.org>; Markus Armbruster
> <armbru@redhat.com>; Li Zhijian <lizhijian@cn.fujitsu.com>
> Subject: Re: [PATCH V4 1/3] net/filter: Remove vnet_hdr from filter-mirror
> and filter-redirector
> 
> On Wed, Oct 27, 2021 at 2:40 PM Zhang, Chen <chen.zhang@intel.com>
> wrote:
> >
> >
> >
> > > -----Original Message-----
> > > From: Jason Wang <jasowang@redhat.com>
> > > Sent: Wednesday, October 27, 2021 2:24 PM
> > > To: Zhang, Chen <chen.zhang@intel.com>
> > > Cc: qemu-dev <qemu-devel@nongnu.org>; Markus Armbruster
> > > <armbru@redhat.com>; Li Zhijian <lizhijian@cn.fujitsu.com>
> > > Subject: Re: [PATCH V4 1/3] net/filter: Remove vnet_hdr from
> > > filter-mirror and filter-redirector
> > >
> > >
> > > 在 2021/10/27 下午2:19, Zhang, Chen 写道:
> > > >>
> > > mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_
> > > h
> > > >> dr
> > > >> _support][,position=head|tail|id=<id>][,insert=behind|before]``
> > > >>> +    ``-object
> > > >>> + filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all
> > > >>> + |rx| tx [,position=head|tail|id=<id>][,insert=behind|before]``
> > > >> I wonder if we break management layer. If yes, maybe it's better
> > > >> to keep the vnet_hdr_support here.
> > > > Yes and no,   With this series of patches, filters have ability to
> automatically
> > > > Configure the appropriate vnet_hdr_support flag according to the
> > > > current
> > > environment.
> > > > And can report error when can't fixing the vnet_hdr(The user
> > > > cannot fix it
> > > from the previous way ).
> > > > So I think no need for the user to configure this option, some
> > > > relevant
> > > background knowledge required.
> > > >
> > > > For the management layer, keep the vnet_hdr_support may be
> > > meaningless except for compatibility.
> > > > In this situation, Do you think we still need to keep the
> > > > vnet_hdr_support
> > > for management layer?
> > >
> > >
> > > So it depends on whether management layer like libvirt has already
> > > supported this. If yes, we may get errors using new qemu with old libvirt?
> >
> > As far as I know, Current management layer like upstream libvirt is no COLO
> official support yet.
> > And some real CSPs use libvirt passthrough qmp command to Qemu for
> manage COLO VM.
> 
> So the question still, it looks to me it requires the modification of the 
> layers
> on top of libvirt? If the answer is yes, we'd better keep that compatibility.
> 

Yes, I will keep the vnet_hdr_support and add some comments to update it in 
next version.

Thanks
Chen

> > It is no harm to users to reduce some unnecessary parameters. But if
> > you think compatibility is more important, I will restore this parameter in
> next version.
> 
> Thanks
> 
> >
> > Thanks
> > Chen
> >
> >
> >
> >
> > >
> > > Thanks
> > >
> > > > Enable/disable it do the same things for filters.
> > > >
> > > > Thanks
> > > > Chen
> > > >
> >