Linux RDMA and InfiniBand development
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From: Leon Romanovsky <leon@kernel.org>
To: Parav Pandit <parav@nvidia.com>
Cc: "Ertman, David M" <david.m.ertman@intel.com>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH 1/6] Add ancillary bus support
Date: Fri, 2 Oct 2020 14:45:45 +0300	[thread overview]
Message-ID: <20201002114545.GB3094@unreal> (raw)
In-Reply-To: <BY5PR12MB432201FCEA970DA28AB06166DC310@BY5PR12MB4322.namprd12.prod.outlook.com>

On Fri, Oct 02, 2020 at 11:27:43AM +0000, Parav Pandit wrote:
>
>
> > From: Leon Romanovsky <leon@kernel.org>
> > Sent: Friday, October 2, 2020 4:44 PM
>
> [..]
> > > > ../../../devices/pci0000:00/0000:00:0b.0/mlx5_core.eth.2
> > > This gives you the ability to not load the netdevice and rdma device of a VF
> > and only load the vdpa device.
> > > These are real use case that users have asked for.
> > > In use case one, they are only interested in rdma device.
> > > In second use case only vdpa device.
> > > How shall one achieve that without spinning of the device for each class?
> >
> > Why will it be different if ancillary device is small PCI core?
> > If you want RDMA, you will use specific ancillary driver that connects to that
> > small PCI logic.
>
> I didn't follow, wwhat is PCI core and PCI logic in this context?

mlx5_core is PCI core/logic - ancillary device
mlx5_ib/mlx5_en/mlx5_vdpa - ancillary drivers

>
> Not sure if you understood the use case.
> Let me try again.
> Let say there are 4 VFs enabled.
> User would not like to create netdev for 3 VFs (0 to 2) ; user only wants rdma device for these VFs 0 to 2.
> User wants only vdpa device for 4th VF.
> User doesn't want to create rdma device and netdevice for the 4th VF.
> How one shall achieve this?

It depends on how N-to-1 bus will be implemented. For example, devlink
already allows to disable RoCE on specific function, nothing prohibits
to extend it to support other classes.

> It is easily achievable with current ancillary device instantiation per class proposal.

It is byproduct of 1-to-1 connection and not specific design decision.

>
> > Being nice to the users and provide clean abstraction are important goals too.
> Which part of this makes not_nice_to_users and what is not abstracted.
> I lost you.

Your use case perfectly presented not_nice_to_users thing. Users are
interested to work on functions (VF/PF/SF) and configure them without
need to dig into the sysfs directories to connect ancillary classes
and their indexes to the real functions.

Thanks

  reply	other threads:[~2020-10-02 11:45 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-01  5:05 [PATCH 0/6] Ancillary bus implementation and SOF multi-client support Dave Ertman
2020-10-01  5:05 ` [PATCH 1/6] Add ancillary bus support Dave Ertman
2020-10-01  8:32   ` Leon Romanovsky
2020-10-01 17:20     ` Ertman, David M
2020-10-01 17:40       ` Leon Romanovsky
2020-10-01 18:29         ` Parav Pandit
2020-10-01 19:32           ` Leon Romanovsky
2020-10-02  5:29             ` Parav Pandit
2020-10-02  6:20               ` Leon Romanovsky
2020-10-02  8:42                 ` Parav Pandit
2020-10-02 11:13                   ` Leon Romanovsky
2020-10-02 11:27                     ` Parav Pandit
2020-10-02 11:45                       ` Leon Romanovsky [this message]
2020-10-02 11:56                         ` Parav Pandit
2020-10-01  5:05 ` [PATCH 2/6] ASoC: SOF: Introduce descriptors for SOF client Dave Ertman
2020-10-01  5:05 ` [PATCH 3/6] ASoC: SOF: Create client driver for IPC test Dave Ertman
2020-10-01  5:05 ` [PATCH 4/6] ASoC: SOF: ops: Add ops for client registration Dave Ertman
2020-10-01  5:05 ` [PATCH 5/6] ASoC: SOF: Intel: Define " Dave Ertman
2020-10-01  5:05 ` [PATCH 6/6] ASoC: SOF: debug: Remove IPC flood test support in SOF core Dave Ertman
2020-10-03  9:04 ` [PATCH 0/6] Ancillary bus implementation and SOF multi-client support Leon Romanovsky
2020-10-03  9:10   ` Greg KH
2020-10-03  9:24     ` Leon Romanovsky
2020-10-03  9:32       ` Greg KH
2020-10-05  1:20     ` Ertman, David M

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