[Qemu-discuss] changing from net to netdev with vde switches and double nics

[Paolo]

Hello everyone,

I'm at loss as to how to translate from net to netdev syntax the following 
lines:

NET0="-net vde,vlan=0,sock=/var/run/vde.ctl00 -net 
nic,vlan=0,model=rtl8139,macaddr=$NIC0MAC -net 
tap,vlan=0,ifname=pub2,script=no,downscript=no"

NET1="-net vde,vlan=1,sock=/var/run/vde.ctl01 -net 
nic,vlan=1,model=rtl8139,macaddr=$NIC1MAC -net 
tap,vlan=1,ifname=prv2,script=no,downscript=no"

Usage for lines above is: qemu blah blah blah $NET0 $NET1 blah blah
(obviously NIC0MAC and NIC1MAC are declared before in the script)

these syntax, which has been working flawlessly for ages on my pc, creates two 
network cards (pubX, prvX) for each one of my virtual machines. Each of the two 
network cards is attached to a vde switch, so all of pubX cards (X is the 
machine) are attached to vsw0 (virtaul switch 0) and all of prvX cards are 
attached to vsw1. The rationale behind this is to attach each qemu machine to a 
private vlan (172.16.y.z) and to a public vlan (192.168.w.t) at the same time.
This way the public lan is used when connected to the internet, the private lan 
works always (i.e. with the router inaccessible) for accessing samba 
directories on the host (of course, firewalled, ip restricted and so on).

Translation from net to netdev is simple for the nic (-device) part and for the 
tap part alike, but how can I tell qemu that the vdeswitch with socket 
/var/run/vde.ctl00 belongs to the same virtual lan of tap pub2 with device 
rtl8139 and mac address NIC0MAC?

Translating from net to netdev we lose the vlan=X info.

Thank you for reading

Paul