Re: [PATCH qemu-kvm] Add raw(af_packet) network backend to qemu

[Anthony Liguori <anthony@codemonkey.ws>]

On 01/27/2010 03:24 AM, Michael S. Tsirkin wrote:
> I am not sure I agree with this sentiment.  The main issue being that
> macvtap doesn't exist on all kernels :).

Neither does vhost ;-)  If it were just that as the difference, I'd be 
inclined to agree, but macvtap is much better from a security PoV.

>> Not to mention that from a user perspective, raw makes almost no sense
>> as it's an obscure socket protocol family.
>>
>> A user wants to do useful things like bridged networking or direct VF
>> assignment.  We should have -net backends that reflect things that make
>> sense to a user.
>>
>> Regards,
>>
>> Anthony Liguori
>>      
>
> I agree to that. People don't even seem to agree whether it's a raw
> socket or a packet socket :) We need a better name for this option: what
> it really does is rely on an external device to loopback a packet to us,
> so how about -net loopback or -net extbridge?
>    

Specifically for VEPA, something like:

-net extbridge,if=eth0

or even

-net vepa,if=eth0

Would be fantastic.  I think the best way to achieve this is to 
introduce a small helper that gets called and can create a macvtap 
device and hand the file descriptor back to qemu :-)  A builtin backend 
would also be fine since we don't have the helper infrastructure.

Regards,

Anthony Liguori