[libvirt] Re: Supporting vhost-net and macvtap in libvirt for QEMU
Anthony Liguori
aliguori at linux.vnet.ibm.com
Thu Dec 17 19:43:35 UTC 2009
Arnd Bergmann wrote:
> On Thursday 17 December 2009, Daniel P. Berrange wrote:
>
>> On Wed, Dec 16, 2009 at 07:48:08PM -0600, Anthony Liguori wrote:
>>
>>
>>> The more interesting invocation of vhost-net though is one where the
>>> vhost-net device backs directly to a physical network card. In this
>>> mode, vhost should get considerably better performance than the current
>>> implementation. I don't know the syntax yet, but I think it's
>>> reasonable to assume that it will look something like -net
>>> tap,dev=eth0. The effect will be that eth0 is dedicated to the guest.
>>>
>> Ok, so in this model you have to create a dedicated ethXX device for
>> every guest, no sharing ?
>>
>
> I think so, but it could be any of
> * a physical NIC dedicated to the guest, e.g. if you want to run a firewall
> on that guest and provide connectivity to all other guests to that, or if
> you have lots of real NICs
> * an IOV adapter with separate physical or virtual functions
> * a VMDq adapter that shows multiple queues on the same PCI function
> as separate network interfaces
> * a macvlan device in VEPA or bridge mode
>
I don't think a macvlan device is quite the same thing (mainly because
there is not finite number of them). I think <source vepa="on"
dev="eth0"/> probably would make more sense as a UI.
But then libvirt needs to be able to create/destroy macvlan devices on
demand.
---
Regards,
Anthony Liguori
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