RE: [net-next v2 1/1] virtual-bus: Implementation of Virtual Bus

[Parav Pandit <parav@mellanox.com>]

> From: Jason Wang <jasowang@redhat.com>
> Subject: Re: [net-next v2 1/1] virtual-bus: Implementation of Virtual Bus
> 
> 
[..]

> 
> Probably, for virtio mdev we need more than just matching: life cycle
> management, cooperation with VFIO and we also want to be prepared for
> the device slicing (like sub functions).

Well I am revising my patches to life cycle sub functions via devlink interface for few reasons, as

(a) avoid mdev bus abuse (still named as mdev in your v13 series, though it is actually for vfio-mdev)
(b) support iommu
(c) manage and have coupling with devlink eswitch framework, which is very rich in several aspects
(d) get rid of limited sysfs interface for mdev creation, as netlink is standard and flexible to add params etc.

If you want to get a glimpse of old RFC work of my revised series, please refer to [1].

Jiri, Jason, me think that even virtio accelerated devices will need eswitch support. And hence, life cycling virtio accelerated devices via devlink makes a lot of sense to us.
This way user has single tool to choose what type of device he want to use (similar to ip link add link type).
So sub function flavour will be something like (virtio or sf).

So I am reviving my old RFC [1] back now in few days as actual patches based on series [2].

[1] https://lkml.org/lkml/2019/3/1/19
[2] https://lore.kernel.org/linux-rdma/20191107160448.20962-1-parav@mellanox.com/