Linux-RDMA Archive on lore.kernel.org
 help / color / Atom feed
From: Jason Wang <jasowang@redhat.com>
To: Jason Gunthorpe <jgg@ziepe.ca>,
	Alex Williamson <alex.williamson@redhat.com>
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: Mon, 11 Nov 2019 10:19:23 +0800
Message-ID: <30d00588-cc19-fdc8-330e-d98b8611a75e@redhat.com> (raw)
In-Reply-To: <20191108210545.GG10956@ziepe.ca>


On 2019/11/9 上午5:05, Jason Gunthorpe wrote:
> On Fri, Nov 08, 2019 at 01:34:35PM -0700, Alex Williamson wrote:
>> 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,
> Well, I think Greg just objected pretty strongly.
>
> IMHO it is wrong to turn mdev into some API multiplexor. That is what
> the driver core already does and AFAIK your bus type is supposed to
> represent your API contract to your drivers.
>
> Since the bus type is ABI, 'mdev' is really all about vfio I guess?
>
> Maybe mdev should grow by factoring the special GUID life cycle stuff
> into a helper library that can make it simpler to build proper API
> specific bus's using that lifecycle model? ie the virtio I saw
> proposed should probably be a mdev-virtio bus type providing this new
> virtio API contract using a 'struct mdev_virtio'?


Yes, and probably just decouple the vfio a little bit more from mdev, 
and allow mdev to register multiple types of buses. Vfio-mdev still go 
for mdev bus, but for virtio and other they will go their own.

Thanks


>
> I only looked briefly but mdev seems like an unusual way to use the
> driver core. *generally* I would expect that if a driver wants to
> provide a foo_device (on a foo bus, providing the foo API contract) it
> looks very broadly like:
>
>    struct foo_device {
>         struct device dev;
>         const struct foo_ops *ops;
>    };
>    struct my_foo_device {
>        struct foo_device fdev;
>    };
>
>    foo_device_register(&mydev->fdev);
>
> Which means we can use normal container_of() patterns, while mdev
> seems to want to allocate all the structs internally.. I guess this is
> because of how the lifecycle stuff works? From a device core view it
> looks quite unnatural.
>
> Jason


  parent reply index

Thread overview: 131+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-07 16:04 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
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
2019-11-09  0:12                   ` Jason Gunthorpe
2019-11-09  0:45                     ` Parav Pandit
2019-11-11  2:19                 ` Jason Wang [this message]
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 publically 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=30d00588-cc19-fdc8-330e-d98b8611a75e@redhat.com \
    --to=jasowang@redhat.com \
    --cc=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

Linux-RDMA Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-rdma/0 linux-rdma/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-rdma linux-rdma/ https://lore.kernel.org/linux-rdma \
		linux-rdma@vger.kernel.org
	public-inbox-index linux-rdma

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-rdma


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git