Re: [PATCH v3 3/6] vbus: add a "vbus-proxy" bus model for vbus_driverobjects

From: Gregory Haskins
Date: Wed Aug 19 2009 - 07:52:18 EST


Avi Kivity wrote:
> On 08/19/2009 02:40 PM, Gregory Haskins wrote:
>>
>>>>>> So if I whip up a virtio-net backend for vbus with a PCI compliant
>>>>>> connector, you are happy?
>>>>>>
>>>>>>
>>>>>>
>>>>> This doesn't improve virtio-net in any way.
>>>>>
>>>>>
>>>> Any why not? (Did you notice I said "PCI compliant", i.e. over
>>>> virtio-pci)
>>>>
>>>>
>>> Because virtio-net will have gained nothing that it didn't have before.
>>>
>> ??
>>
>> *) ABI is virtio-pci compatible, as you like
>>
>
> That's not a gain, that's staying in the same place.
>
>> *) fast-path is in-kernel, as we all like
>>
>
> That's not a gain as we have vhost-net (sure, in development, but your
> proposed backend isn't even there yet).
>
>> *) model is in vbus so it would work in all environments that vbus
>> supports.
>>
>
> The ABI can be virtio-pci compatible or it can be vbus-comaptible. How
> can it be both? The ABIs are different.
>
> Note that if you had submitted a virtio-net backend I'd have asked you
> to strip away all the management / bus layers and we'd have ended up
> with vhost-net.

Sigh...


>
>>>>> virtio already supports this model; see lguest and s390. Transporting
>>>>> virtio over vbus and vbus over something else doesn't gain anything
>>>>> over
>>>>> directly transporting virtio over that something else.
>>>>>
>>>>>
>>>> This is not what I am advocating.
>>>>
>>>>
>>>>
>>> What are you advocating? As far as I can tell your virtio-vbus
>>> connector plus the vbus-kvm connector is just that.
>>>
>> I wouldn't classify it anything like that, no. Its just virtio over
>> vbus.
>>
>
> We're in a loop. Doesn't virtio over vbus need a virtio-vbus
> connector? and doesn't vbus need a connector to talk to the hypervisor?
>

No, it doesnt work like that. There is only one connector.

Kind Regards,
-Greg

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