From: Alex Williamson <alex.williamson@redhat.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>,
Parav Pandit <parav@mellanox.com>, Jiri Pirko <jiri@resnulli.us>,
David M <david.m.ertman@intel.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"davem@davemloft.net" <davem@davemloft.net>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Saeed Mahameed <saeedm@mellanox.com>,
"kwankhede@nvidia.com" <kwankhede@nvidia.com>,
"leon@kernel.org" <leon@kernel.org>,
"cohuck@redhat.com" <cohuck@redhat.com>,
Jiri Pirko <jiri@mellanox.com>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
Or Gerlitz <gerlitz.or@gmail.com>
Subject: Re: [PATCH net-next 00/19] Mellanox, mlx5 sub function support
Date: Fri, 8 Nov 2019 13:34:35 -0700 [thread overview]
Message-ID: <20191108133435.6dcc80bd@x1.home> (raw)
In-Reply-To: <20191108201253.GE10956@ziepe.ca>
On Fri, 8 Nov 2019 16:12:53 -0400
Jason Gunthorpe <jgg@ziepe.ca> wrote:
> On Fri, Nov 08, 2019 at 11:12:38AM -0800, Jakub Kicinski wrote:
> > On Fri, 8 Nov 2019 15:40:22 +0000, Parav Pandit wrote:
> > > > The new intel driver has been having a very similar discussion about how to
> > > > model their 'multi function device' ie to bind RDMA and other drivers to a
> > > > shared PCI function, and I think that discussion settled on adding a new bus?
> > > >
> > > > Really these things are all very similar, it would be nice to have a clear
> > > > methodology on how to use the device core if a single PCI device is split by
> > > > software into multiple different functional units and attached to different
> > > > driver instances.
> > > >
> > > > Currently there is alot of hacking in this area.. And a consistent scheme
> > > > might resolve the ugliness with the dma_ops wrappers.
> > > >
> > > > We already have the 'mfd' stuff to support splitting platform devices, maybe
> > > > we need to create a 'pci-mfd' to support splitting PCI devices?
> > > >
> > > > I'm not really clear how mfd and mdev relate, I always thought mdev was
> > > > strongly linked to vfio.
> > > >
> > >
> > > Mdev at beginning was strongly linked to vfio, but as I mentioned
> > > above it is addressing more use case.
> > >
> > > I observed that discussion, but was not sure of extending mdev further.
> > >
> > > One way to do for Intel drivers to do is after series [9].
> > > Where PCI driver says, MDEV_CLASS_ID_I40_FOO
> > > RDMA driver mdev_register_driver(), matches on it and does the probe().
> >
> > Yup, FWIW to me the benefit of reusing mdevs for the Intel case vs
> > muddying the purpose of mdevs is not a clear trade off.
>
> IMHO, mdev has amdev_parent_ops structure clearly intended to link it
> to vfio, so using a mdev for something not related to vfio seems like
> a poor choice.
Unless there's some opposition, I'm intended to queue this for v5.5:
https://www.spinics.net/lists/kvm/msg199613.html
mdev has started out as tied to vfio, but at it's core, it's just a
device life cycle infrastructure with callbacks between bus drivers
and vendor devices. If virtio is on the wrong path with the above
series, please speak up. Thanks,
Alex
> I suppose this series is the start and we will eventually see the
> mlx5's mdev_parent_ops filled in to support vfio - but *right now*
> this looks identical to the problem most of the RDMA capable net
> drivers have splitting into a 'core' and a 'function'
>
> > IMHO MFD should be of more natural use for Intel, since it's about
> > providing different functionality rather than virtual slices of the
> > same device.
>
> I don't think the 'different functionality' should matter much.
>
> Generally these multi-function drivers are build some some common
> 'core' language like queues interrupts, BAR space, etc and then these
> common things can be specialized into netdev, rdma, scsi, etc. So we
> see a general rough design with a core layer managing the raw HW then
> drivers on top of that (including netdev) using that API.
>
> The actual layering doesn't come through in the driver model,
> generally people put all the core stuff in with the netdev and then
> try and shuffle the netdev around as the 'handle' for that core API.
>
> These SFs are pretty similar in that the core physical driver
> continues to provide some software API support to the SF children (at
> least for mlx it is a small API)
>
> For instance mdev has no generic way to learn the BAR struct
> resources, so there is some extra API around the side that does this -
> in this series it is done by hackily co-opting the drvdata to
> something owned by the struct device instead of the device_driver and
> using that to access the API surface on 'struct mlx5_sf *', which
> includes the BAR info and so forth.
>
> This is probably the main difference from MFD. At least the few
> drivers I looked at, did not try and expose an SW API from the 'core'
> to the 'part', everything was usual generic driver resource stuff.
>
> Jason
next prev parent reply other threads:[~2019-11-08 20:34 UTC|newest]
Thread overview: 132+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-07 16:04 [PATCH net-next 00/19] Mellanox, mlx5 sub function support Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 01/19] net/mlx5: E-switch, Move devlink port close to eswitch port Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 02/19] net/mlx5: E-Switch, Add SF vport, vport-rep support Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 03/19] net/mlx5: Introduce SF table framework Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 04/19] net/mlx5: Introduce SF life cycle APIs to allocate/free Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 05/19] net/mlx5: E-Switch, Enable/disable SF's vport during SF life cycle Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 06/19] net/mlx5: Add support for mediated devices in switchdev mode Parav Pandit
2019-11-08 10:32 ` Jiri Pirko
2019-11-08 16:03 ` Parav Pandit
2019-11-08 16:22 ` Jiri Pirko
2019-11-08 16:29 ` Parav Pandit
2019-11-08 18:01 ` Jiri Pirko
2019-11-08 18:04 ` Jiri Pirko
2019-11-08 18:21 ` Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 07/19] vfio/mdev: Introduce sha1 based mdev alias Parav Pandit
2019-11-08 11:04 ` Jiri Pirko
2019-11-08 15:59 ` Parav Pandit
2019-11-08 16:28 ` Jiri Pirko
2019-11-08 11:10 ` Cornelia Huck
2019-11-08 16:03 ` Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 08/19] vfio/mdev: Make mdev alias unique among all mdevs Parav Pandit
2019-11-08 10:49 ` Jiri Pirko
2019-11-08 15:13 ` Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 09/19] vfio/mdev: Expose mdev alias in sysfs tree Parav Pandit
2019-11-08 13:22 ` Jiri Pirko
2019-11-08 18:03 ` Alex Williamson
2019-11-08 18:16 ` Jiri Pirko
2019-11-07 16:08 ` [PATCH net-next 10/19] vfio/mdev: Introduce an API mdev_alias Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 11/19] vfio/mdev: Improvise mdev life cycle and parent removal scheme Parav Pandit
2019-11-08 13:01 ` Cornelia Huck
2019-11-08 16:12 ` Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 12/19] devlink: Introduce mdev port flavour Parav Pandit
2019-11-07 20:38 ` Jakub Kicinski
2019-11-07 21:03 ` Parav Pandit
2019-11-08 1:17 ` Jakub Kicinski
2019-11-08 1:44 ` Parav Pandit
2019-11-08 2:20 ` Jakub Kicinski
2019-11-08 2:31 ` Parav Pandit
2019-11-08 9:46 ` Jiri Pirko
2019-11-08 15:45 ` Parav Pandit
2019-11-08 16:31 ` Jiri Pirko
2019-11-08 16:43 ` Parav Pandit
2019-11-08 18:11 ` Jiri Pirko
2019-11-08 18:23 ` Parav Pandit
2019-11-08 18:34 ` Jiri Pirko
2019-11-08 18:56 ` Parav Pandit
2019-11-08 9:30 ` Jiri Pirko
2019-11-08 15:41 ` Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 13/19] net/mlx5: Register SF devlink port Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 14/19] net/mlx5: Share irqs between SFs and parent PCI device Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 15/19] net/mlx5: Add load/unload routines for SF driver binding Parav Pandit
2019-11-08 9:48 ` Jiri Pirko
2019-11-08 11:13 ` Jiri Pirko
2019-11-07 16:08 ` [PATCH net-next 16/19] net/mlx5: Implement dma ops and params for mediated device Parav Pandit
2019-11-07 20:42 ` Jakub Kicinski
2019-11-07 21:30 ` Parav Pandit
2019-11-08 1:16 ` Jakub Kicinski
2019-11-08 6:37 ` Christoph Hellwig
2019-11-08 15:29 ` Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 17/19] net/mlx5: Add mdev driver to bind to mdev devices Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 18/19] Documentation: net: mlx5: Add mdev usage documentation Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 19/19] mtty: Optionally support mtty alias Parav Pandit
2019-11-08 6:26 ` Leon Romanovsky
2019-11-08 10:45 ` Jiri Pirko
2019-11-08 15:08 ` Parav Pandit
2019-11-08 15:15 ` Jiri Pirko
2019-11-08 13:46 ` Cornelia Huck
2019-11-08 15:10 ` Parav Pandit
2019-11-08 15:28 ` Cornelia Huck
2019-11-08 15:30 ` Parav Pandit
2019-11-08 17:54 ` Alex Williamson
2019-11-08 9:51 ` [PATCH net-next 01/19] net/mlx5: E-switch, Move devlink port close to eswitch port Jiri Pirko
2019-11-08 15:50 ` Parav Pandit
2019-11-07 17:03 ` [PATCH net-next 00/19] Mellanox, mlx5 sub function support Leon Romanovsky
2019-11-07 20:10 ` Parav Pandit
2019-11-08 6:20 ` Leon Romanovsky
2019-11-08 15:01 ` Parav Pandit
2019-11-07 20:32 ` Jakub Kicinski
2019-11-07 20:52 ` Parav Pandit
2019-11-08 1:16 ` Jakub Kicinski
2019-11-08 1:49 ` Parav Pandit
2019-11-08 2:12 ` Jakub Kicinski
2019-11-08 12:12 ` Jiri Pirko
2019-11-08 14:40 ` Jason Gunthorpe
2019-11-08 15:40 ` Parav Pandit
2019-11-08 19:12 ` Jakub Kicinski
2019-11-08 20:12 ` Jason Gunthorpe
2019-11-08 20:20 ` Parav Pandit
2019-11-08 20:32 ` Jason Gunthorpe
2019-11-08 20:52 ` gregkh
2019-11-08 20:34 ` Alex Williamson [this message]
2019-11-08 21:05 ` Jason Gunthorpe
2019-11-08 21:19 ` gregkh
2019-11-08 21:52 ` Alex Williamson
2019-11-08 22:48 ` Parav Pandit
2019-11-09 0:57 ` Jason Gunthorpe
2019-11-09 17:41 ` Jakub Kicinski
2019-11-10 19:04 ` Jason Gunthorpe
2019-11-10 19:48 ` Parav Pandit
2019-11-11 14:17 ` Jiri Pirko
2019-11-11 14:58 ` Parav Pandit
2019-11-11 15:06 ` Jiri Pirko
2019-11-19 4:51 ` Parav Pandit
2019-11-09 0:12 ` Jason Gunthorpe
2019-11-09 0:45 ` Parav Pandit
2019-11-11 2:19 ` Jason Wang
2019-11-08 21:45 ` Jakub Kicinski
2019-11-09 0:44 ` Jason Gunthorpe
2019-11-09 8:46 ` gregkh
2019-11-09 11:18 ` Jiri Pirko
2019-11-09 17:28 ` Jakub Kicinski
2019-11-10 9:16 ` gregkh
2019-11-09 17:27 ` Jakub Kicinski
2019-11-10 9:18 ` gregkh
2019-11-11 3:46 ` Jakub Kicinski
2019-11-11 5:18 ` Parav Pandit
2019-11-11 13:30 ` Jiri Pirko
2019-11-11 14:14 ` gregkh
2019-11-11 14:37 ` Jiri Pirko
2019-11-10 19:37 ` Jason Gunthorpe
2019-11-11 3:57 ` Jakub Kicinski
2019-11-08 16:06 ` Parav Pandit
2019-11-08 19:06 ` Jakub Kicinski
2019-11-08 19:34 ` Parav Pandit
2019-11-08 19:48 ` Jakub Kicinski
2019-11-08 19:41 ` Jiri Pirko
2019-11-08 20:40 ` Parav Pandit
2019-11-08 21:21 ` Jakub Kicinski
2019-11-08 21:39 ` Jiri Pirko
2019-11-08 21:51 ` Jakub Kicinski
2019-11-08 22:21 ` Jiri Pirko
2019-11-07 23:57 ` David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191108133435.6dcc80bd@x1.home \
--to=alex.williamson@redhat.com \
--cc=cohuck@redhat.com \
--cc=davem@davemloft.net \
--cc=david.m.ertman@intel.com \
--cc=gerlitz.or@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=jakub.kicinski@netronome.com \
--cc=jgg@ziepe.ca \
--cc=jiri@mellanox.com \
--cc=jiri@resnulli.us \
--cc=kvm@vger.kernel.org \
--cc=kwankhede@nvidia.com \
--cc=leon@kernel.org \
--cc=linux-rdma@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=parav@mellanox.com \
--cc=saeedm@mellanox.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).