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

[Paolo]

> On Wed, 30 Aug 2017 08:03:31 +0200
> Thomas Huth wrote:

> >  NET0="-net vde,vlan=0,sock=/var/run/vde.ctl00 -net 
> > nic,vlan=0,model=rtl8139,macaddr=$NIC0MAC"
> >  NET1="-net vde,vlan=1,sock=/var/run/vde.ctl01 -net 
> > nic,vlan=1,model=rtl8139,macaddr=$NIC1MAC"
> > 
> > Now I guess this is impossbile to achieve with netdev?
> > How may I tell to qemu that the guest's NIC0 has to be wired to the vde 
> > switch vde.ctl00 run on host has, and NIC1 to vde.ctl01?  
> 
> It should be doable. Could you please try something like this:
> 
>  NET0="-netdev vde,id=v0,sock=/var/run/vde.ctl00 -device 
> rtl8139,netdev=v0,mac=$NIC0MAC"
>  NET1="-netdev vde,id=v1,sock=/var/run/vde.ctl01 -device 
> rtl8139,netdev=v1,mac=$NIC1MAC"
> 
> I haven't tested it though, so you still might have to tweak it. Run qemu
> with "-device rtl8139,?" to see the options of the rtl8139 device.

Just tested. Those lines work very well. Here are mines (I've a group kvm):

NET0="-netdev vde,id=v0,sock=/var/run/vde.ctl00,group=kvm,mode=0770 -device 
rtl8139,netdev=v0,mac=$NIC0MAC"
NET1="-netdev vde,id=v1,sock=/var/run/vde.ctl01,group=kvm,mode=0770 -device 
rtl8139,netdev=v1,mac=$NIC1MAC"

Can't understand why the guest OS (windows 7) reinstalls the network cards 
(nothing should have changed from it's point of view), but it's ok.
All I needed to keep the list of NICs short and minimal, was to disable and 
uninstall the two network cards inside the windows environment before the 
migration from the -net to -netdev syntax, and, of course to reassign the 
IP/subnet mask/etc after the next boot.

Thank you

Paul