Re: [dpdk-dev] [RFC 00/14] mlx5: support SubFunction

[Parav Pandit <parav@nvidia.com>]

Hi Chenbo,

> From: Xia, Chenbo <chenbo.xia@intel.com>
> Sent: Tuesday, June 15, 2021 7:41 AM
> 
> Hi Thomas,
> 
> > From: Thomas Monjalon <thomas@monjalon.net>
> > Sent: Friday, June 11, 2021 3:54 PM
[..]

> 
> Yes. In our term it's called Assignable Device Interface (ADI) introduced in
> Intel Scalable IOV (https://01.org/blogs/2019/assignable-interfaces-intel-
> scalable-i/o-virtualization-linux)
> 
> And vfio-mdev is chosen to be the software framework for it. I start to realize
> there is difference between SF and ADI: SF considers multi-function devices
> which may include net/regex/vdpa/... 
Yes. net, rdma, vdpa, regex ++.
And eventually vfio_device to map to VM too.

Non mdev framework is chosen so that all the use cases of kernel only, or user only or mix modes can be supported.

> But ADI only focuses on the
> virtualization of the devices and splitting devices to logic parts and providing
> huge number of interfaces to host APP. I think SF also considers this but is
> mainly used for multi-function devices (like DPU in your term?
> Correct me if I'm wrong).
> 
SF also supports DPU mode too but it is in addition to above use cases.
SF will expose mdev (or a vfio_device) to map to a VM.

> And I also noticed that the mdev-based interface can only be used in
> userspace but aux-based interface can also be used by other kernel sub-
> system (like for net, wrap it as netdev).
Correct.