Re: [dpdk-dev] discussion: creating a new class for vdpa driversxiao.w.wang@intel.com

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 12/6/19 10:05 AM, Andrew Rybchenko wrote:
> On 12/6/19 8:32 AM, Liang, Cunming wrote:
>>
>>
>>> -----Original Message-----
>>> From: Bie, Tiwei <tiwei.bie@intel.com>
>>> Sent: Friday, December 6, 2019 12:28 PM
>>> To: Matan Azrad <matan@mellanox.com>
>>> Cc: Wang, Xiao W <xiao.w.wang@intel.com>; Thomas Monjalon
>>> <thomas@monjalon.net>; maxime.coquelin@redhat.com; Wang, Zhihong
>>> <zhihong.wang@intel.com>; Yigit, Ferruh <ferruh.yigit@intel.com>; Shahaf Shuler
>>> <shahafs@mellanox.com>; Ori Kam <orika@mellanox.com>; dev@dpdk.org; Slava
>>> Ovsiienko <viacheslavo@mellanox.com>; Asaf Penso <asafp@mellanox.com>; Olga
>>> Shern <olgas@mellanox.com>; Liang, Cunming <cunming.liang@intel.com>
>>> Subject: Re: discussion: creating a new class for vdpa
>>> driversxiao.w.wang@intel.com
>>>
>>> On Thu, Dec 05, 2019 at 01:26:36PM +0000, Matan Azrad wrote:
>>>> Hi all
>>>>
>>>> As described in RFC “[RFC] net: new vdpa PMD for Mellanox devices”, a
>>>> new vdpa drivers is going to be added for Mellanox devices – mlx5_vdpa
>>>>
>>>> The only vdpa driver now is the IFC driver that is located in net directory.
>>>>
>>>> The IFC driver and the new mlx5_vdpa driver provide the vdpa ops and
>>>> not the eth_dev ops.
>>>>
>>>> All the others drivers in net provide the eth-dev ops.
>>>>
>>>> I suggest to create a new class for vdpa drivers, to move IFC to this
>>>> class and to add the mlx5_vdpa to this class too.
>>>>
>>>> Later, all the new drivers that implements the vdpa ops will be added
>>>> to the vdpa class.
>>>
>>> +1. Sounds like a good idea to me.
>> +1
> 
> vDPA drivers are vendor-specific and expected to talk to vendor
> NIC. I.e. there are significant chances to share code with
> network drivers (e.g. base driver). Should base driver be moved
> to drivers/common in this case or is it still allows to have
> vdpa driver in drivers/net together with ethdev driver?
> 

That's a good point.

For example, for the Virtio vDPA driver, I placed it in th Virtio PMD
directory, so that we can re-use the Virtio-pci layer.
On the other hand, for the specific Virtio case, it may be preferable
to have a common directory. Doing that, the Virtio-pci layer could be
reused by Virtio PMD, Virtio vDPA, but also Virtio Crypto drivers.

I plan to submit again my Virtio vDPA next week as it didn't make it in
v19.11. I'll wait for an agreement on this topic before proceeding.

Thanks,
Maxime