Re: [Qemu-devel] [ Patch 1/2] virtio-net rsc: support coalescing ipv4 tcp traffic

[Jason Wang]

On 03/18/2016 02:38 PM, Wei Xu wrote:
>
>
> On 2016年03月18日 13:20, Jason Wang wrote:
>>
>> On 03/18/2016 12:17 PM, Wei Xu wrote:
>>>>>>> +static ssize_t virtio_net_receive(NetClientState *nc,
>>>>>>> +                                  const uint8_t *buf, size_t size)
>>>>>>> +{
>>>>>>> +    if (virtio_net_rsc_bypass) {
>>>>>>> +        return virtio_net_do_receive(nc, buf, size);
>>>>>> You need a feature bit for this and compat it for older machine
>>>>>> types.
>>>>>> And also need some work on virtio spec I think.
>>>>> yes, not sure which way is good to support this, hmp/qmp/ethtool,
>>>>> this
>>>>> is gonna to support win guest,
>>>>> so need a well-compatible interface, any comments?
>>>> I think this should be implemented through feature bits/negotiation
>>>> instead of something like ethtool.
>>> Looks this feature should be turn on/off dynamically due to the spec,
>>> so maybe this should be managed from the guest, is there any reference
>>> code for this?
>> Then you may want to look at implementation of
>> VIRTIO_NET_F_CTRL_GUEST_OFFLOADS.
> Have a short look at it, do you know how to control the feature bit? 
> both when lauching vm and changing it during runtime? 

Virtio spec and maybe windows driver source code can give you the answer.