[dpdk-dev] [PATCH v2] kni: use kni_ethtool_ops only with unknown drivers

[Ferruh Yigit]

On 12/1/2018 11:12 AM, Igor Ryzhov wrote:
> Hi Stephen,
> 
> I also do not see the point of the current implementation of ethtool
> support.
> That's why I sent this patch – it enables ethtool_ops for all devices,
> independent of the underlying driver.

I tried to clarify this in the patch, but it doesn't enable ethtool_ops for
underlying driver.

> Right now only .get_link is supported, but I am thinking about
> implementation of a larger set of functions, using req/resp queue, like
> netdev_ops functions are working.

You should go to userspace to get device information, right. Since now userspace
has the driver. So a channel between kernel and userspace is required.
Please share your plans/design on this support.

> 
> Regarding the KNI itself, we use it as Linux mirror of physical port for:
> 1. Port configuration from Linux – such functions as set_mac, change_mtu,
> etc. And ethtool_ops will be used the same way.
> 2. Passing control-plane packets to Linux.
> 
> Can virtio user be used the same way, as a mirror of physical port?
> 
> Best regards,
> Igor
> 
> On Sat, Dec 1, 2018 at 2:38 AM Stephen Hemminger <stephen at networkplumber.org>
> wrote:
> 
>> On Fri, 30 Nov 2018 22:47:50 +0300
>> Igor Ryzhov <iryzhov at nfware.com> wrote:
>>
>>> Current implementation of kni_ethtool_ops just uses corresponding
>>> ethtool_ops function of underlying driver for all functions except for
>>> .get_link. This commit sets kni->net_dev->ethtool_ops directly to the
>>> ethtool_ops of the corresponding driver.
>>>
>>> For unknown drivers (all but ixgbe and i40e) we still use
>>> kni_ethtool_ops with implemented .get_link function.
>>>
>>> Signed-off-by: Igor Ryzhov <iryzhov at nfware.com>
>>
>> Why does KNI still support ethtool which:
>>   1. Only works on a subset of devices
>>   2. Requires a 3rd implmentation of the HW device (Linux, DPDK, and KNI)
>>
>> Then again why does KNI exist at all? What is missing from virtio user
>> which
>> is faster anyway.
>>