Re: [Qemu-devel] [PATCH] virtio-net: Do not filter VLANs without F_CTRL_VLAN

[Amos Kong]

On Wed, Mar 19, 2014 at 11:38:57PM +0100, Stefan Fritsch wrote:
> Hi,
> 
> Am Dienstag, 25. Februar 2014, 11:06:33 schrieb Amos Kong:
> > > > On Wed, Feb 12, 2014 at 10:46:28PM +0100, Stefan Fritsch wrote:
> > > > > If VIRTIO_NET_F_CTRL_VLAN is not negotiated, do not filter out
> > > > > all
> > > > > VLAN-tagged packets but send them to the guest.
> 
> 
> AFAICS, no fix has been committed, yet. Is there anything I need to do 
> to get this fixed?
 
Michael asked in IRC to continually add a RxState for vlan in
RxFilter notification through QMP events.

(sorry I didn't talk too much becaused I'm in meeting)

I mentioned in [1] [2], we don't need to add this new state
if we apply patch Stefan's patch[3]

Michael said Stefan's fix is wrong, but the problem exists.
The problem is the bug fixed by [3], not the problem that was
mentioned in [4] 


Michael, what's wrong with Stefan's patch?


Thanks, Amos

[1] http://lists.gnu.org/archive/html/qemu-devel/2014-02/msg03835.html
[2] https://lists.gnu.org/archive/html/qemu-devel/2014-02/msg04434.html
[3] virtio-net: Do not filter VLANs without F_CTRL_VLAN
[4] https://lists.gnu.org/archive/html/qemu-devel/2014-02/msg02604.html


> > > > Can we just update receive_filter() to filter out VLAN-tagged
> > > > packets only when VIRTIO_NET_F_CTRL_VLAN is negotiated?
> > 
> > If we change receive_filter(), we also need a flag to indicate
> > management this feature isn't negotiated, management will do some
> > additional operation to host device to get same effect.
> >  
> > 
> > > We could. But this adds a (very small) per-packet overhead while
> > > my patch  only adds overhead during reset. Therefore I didn't
> > > take that approach. But if changing receive_filter() makes
> > > management much easier, that could be acceptable.
> > 
> > Actually your solution is better, QEMU will return a long list
> > [0,1,2,...4095] to management, host device will filter all the vlan
> > packets and send to QEMU.
> > 
> > So the problem raised by mst doesn't exist.
> 
> Cheers,
> Stefan
> 

-- 
                        Amos.