Re: [Qemu-devel] [PATCH] net: Allow specifying ifname for qemu-bridge-helper

[Paolo Bonzini]

Il 30/11/2012 11:02, Michael Tokarev ha scritto:
>> I do like the idea of using a common prefix for the default name
>> of tap devices. Something like "qvif%d" instead of "tap%d" in tap
>> initialization code. But something tells me this could break
>> compatibility with external management software where something
>> might be expecting the interface name to start with tap.
>
> Does any management interface use this bridge-helper functionality? 

Libvirt uses it if you're running libvirtd without privileges.  GNOME
Boxes is a 1-line patch away from using it, but it's Fedora-specific and
not included in any distro.

Paolo

> If it were me, I'd always created the tap fd in the management layer
> and passed the tap fd# (or at least ifname= of an existing iface) to
> qemu.  Bridge helper is useful for users calling qemu directly, not
> for management software.  Sure, such users are also important -
> including compatibility.  But I don't think current unpredictable
> tapNN names was a good idea to start with, and that it's good idea to
> rely on this prefix in firewall rules or whatnot.