[Qemu-devel] Re: [PATCH 9/9] Introduce VLANClientState::cleanup()

[Anthony Liguori <aliguori@us.ibm.com>]

Jan Kiszka wrote:
> That would only allow one such pair per VM.
>   

id basically becomes another type of vlan id.  To have multiple nics, 
you do:

-net tap,vlan=off,id=1234 -net nic,model=virtio,vlan=off,id=1234
-net tap,vlan=off,id=4321 -net nic,model=virtio,vlan=off,id=4321

And this goes back to the notion of having all device 
front-ends/back-ends have some sort of identifier to associate one to 
the other.

> Why not keeping all the existing infrastructure, just locking a vlan
> against becoming more than a point-to-point link once some conflicting
> optimization was applied? That should be easy to implement and to
> explain to the user.
>   

I think you're suggesting the same thing as me, except you are saying 
make vlan=off implicit, and use vlan=XXX instead of id=XXX.

We can still make vlan=off implicit, and default id=0, so that -net tap 
net nic,model=virtio does the right thing.  However, if a user 
explicitly says -net tap,vlan=1 -net nic,model=virtio,vlan=1, it behaves 
like it used to.

-- 
Regards,

Anthony Liguori