[Qemu-discuss] passthrough NIC versus bridge setup in qemu

[Martin T]

Hi!

I set up a quemu virtual machine using virsh in a way that I pass
through my physical USB NIC connected to the host machine directly to
the virtual machine. In other words, I added this to virtual machine
configuration:

    <hostdev mode='subsystem' type='usb' managed='yes'>
      <source>
        <vendor id='0x13b1'/>
        <product id='0x0041'/>
        <address bus='3' device='3'/>
      </source>
      <address type='usb' bus='0' port='1'/>
    </hostdev>

This means that I see my USB NIC in the guest machine with "lsusb" and
I get the IP address from my DHCP server. Does this setup have
advantages over more conventional bridged setup where physical NIC of
the host machine and virtual machine via "tap" interface are connected
to Linux-bridge? Does such pass-through setup provide any performance
benefits? Are there any practical reasons for such a setup?


thanks,
Martin