From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: Yan Zhao <yan.y.zhao@intel.com>,
kvm@vger.kernel.org, libvir-list@redhat.com,
qemu-devel@nongnu.org, kwankhede@nvidia.com, eauger@redhat.com,
xin-ran.wang@intel.com, corbet@lwn.net,
openstack-discuss@lists.openstack.org, shaohe.feng@intel.com,
kevin.tian@intel.com, Parav Pandit <parav@mellanox.com>,
jian-feng.ding@intel.com, dgilbert@redhat.com,
zhenyuw@linux.intel.com, hejie.xu@intel.com,
bao.yumeng@zte.com.cn,
Alex Williamson <alex.williamson@redhat.com>,
eskultet@redhat.com, smooney@redhat.com,
intel-gvt-dev@lists.freedesktop.org,
Cornelia Huck <cohuck@redhat.com>, Jiri Pirko <jiri@mellanox.com>,
dinechin@redhat.com, devel@ovirt.org
Subject: Re: device compatibility interface for live migration with assigned devices
Date: Tue, 18 Aug 2020 09:55:27 +0100 [thread overview]
Message-ID: <20200818085527.GB20215@redhat.com> (raw)
In-Reply-To: <a51209fe-a8c6-941f-ff54-7be06d73bc44@redhat.com>
On Tue, Aug 18, 2020 at 11:24:30AM +0800, Jason Wang wrote:
>
> On 2020/8/14 下午1:16, Yan Zhao wrote:
> > On Thu, Aug 13, 2020 at 12:24:50PM +0800, Jason Wang wrote:
> > > On 2020/8/10 下午3:46, Yan Zhao wrote:
> > > > > driver is it handled by?
> > > > It looks that the devlink is for network device specific, and in
> > > > devlink.h, it says
> > > > include/uapi/linux/devlink.h - Network physical device Netlink
> > > > interface,
> > >
> > > Actually not, I think there used to have some discussion last year and the
> > > conclusion is to remove this comment.
> > >
> > > It supports IB and probably vDPA in the future.
> > >
> > hmm... sorry, I didn't find the referred discussion. only below discussion
> > regarding to why to add devlink.
> >
> > https://www.mail-archive.com/netdev@vger.kernel.org/msg95801.html
> > >This doesn't seem to be too much related to networking? Why can't something
> > >like this be in sysfs?
> >
> > It is related to networking quite bit. There has been couple of
> > iteration of this, including sysfs and configfs implementations. There
> > has been a consensus reached that this should be done by netlink. I
> > believe netlink is really the best for this purpose. Sysfs is not a good
> > idea
>
>
> See the discussion here:
>
> https://patchwork.ozlabs.org/project/netdev/patch/20191115223355.1277139-1-jeffrey.t.kirsher@intel.com/
>
>
> >
> > https://www.mail-archive.com/netdev@vger.kernel.org/msg96102.html
> > >there is already a way to change eth/ib via
> > >echo 'eth' > /sys/bus/pci/drivers/mlx4_core/0000:02:00.0/mlx4_port1
> > >
> > >sounds like this is another way to achieve the same?
> >
> > It is. However the current way is driver-specific, not correct.
> > For mlx5, we need the same, it cannot be done in this way. Do devlink is
> > the correct way to go.
> >
> > https://lwn.net/Articles/674867/
> > There a is need for some userspace API that would allow to expose things
> > that are not directly related to any device class like net_device of
> > ib_device, but rather chip-wide/switch-ASIC-wide stuff.
> >
> > Use cases:
> > 1) get/set of port type (Ethernet/InfiniBand)
> > 2) monitoring of hardware messages to and from chip
> > 3) setting up port splitters - split port into multiple ones and squash again,
> > enables usage of splitter cable
> > 4) setting up shared buffers - shared among multiple ports within one chip
> >
> >
> >
> > we actually can also retrieve the same information through sysfs, .e.g
> >
> > |- [path to device]
> > |--- migration
> > | |--- self
> > | | |---device_api
> > | | |---mdev_type
> > | | |---software_version
> > | | |---device_id
> > | | |---aggregator
> > | |--- compatible
> > | | |---device_api
> > | | |---mdev_type
> > | | |---software_version
> > | | |---device_id
> > | | |---aggregator
> >
>
> Yes but:
>
> - You need one file per attribute (one syscall for one attribute)
> - Attribute is coupled with kobject
>
> All of above seems unnecessary.
>
> Another point, as we discussed in another thread, it's really hard to make
> sure the above API work for all types of devices and frameworks. So having a
> vendor specific API looks much better.
From the POV of userspace mgmt apps doing device compat checking / migration,
we certainly do NOT want to use different vendor specific APIs. We want to
have an API that can be used / controlled in a standard manner across vendors.
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
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next prev parent reply other threads:[~2020-08-18 8:56 UTC|newest]
Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-13 23:29 device compatibility interface for live migration with assigned devices Yan Zhao
2020-07-14 10:21 ` Daniel P. Berrangé
2020-07-14 12:33 ` Sean Mooney
[not found] ` <20200714110148.0471c03c@x1.home>
[not found] ` <eb705c72cdc8b6b8959b6ebaeeac6069a718d524.camel@redhat.com>
2020-07-14 21:15 ` Sean Mooney
2020-07-14 16:16 ` Alex Williamson
2020-07-14 16:47 ` Daniel P. Berrangé
2020-07-14 20:47 ` Alex Williamson
2020-07-15 9:16 ` Daniel P. Berrangé
2020-07-14 17:19 ` Dr. David Alan Gilbert
2020-07-14 20:59 ` Alex Williamson
2020-07-15 8:20 ` Yan Zhao
2020-07-15 8:49 ` Feng, Shaohe
2020-07-17 14:59 ` Alex Williamson
2020-07-17 18:03 ` Dr. David Alan Gilbert
2020-07-17 18:30 ` Alex Williamson
2020-07-15 8:23 ` Dr. David Alan Gilbert
[not found] ` <CAH7mGatPWsczh_rbVhx4a+psJXvkZgKou3r5HrEQTqE7SqZkKA@mail.gmail.com>
2020-07-17 15:18 ` Alex Williamson
2020-07-16 4:16 ` Jason Wang
2020-07-16 8:32 ` Yan Zhao
2020-07-16 9:30 ` Jason Wang
2020-07-17 16:12 ` Alex Williamson
2020-07-20 3:41 ` Jason Wang
2020-07-20 10:39 ` Sean Mooney
2020-07-21 2:11 ` Jason Wang
2020-07-21 0:51 ` Yan Zhao
2020-07-27 7:24 ` Yan Zhao
2020-07-27 22:23 ` Alex Williamson
2020-07-29 8:05 ` Yan Zhao
2020-07-29 11:28 ` Sean Mooney
2020-07-29 19:12 ` Alex Williamson
2020-07-30 3:41 ` Yan Zhao
2020-07-30 13:24 ` Sean Mooney
2020-07-30 17:29 ` Alex Williamson
2020-08-04 8:37 ` Yan Zhao
2020-08-05 9:44 ` Dr. David Alan Gilbert
2020-07-30 1:56 ` Yan Zhao
2020-07-30 13:14 ` Sean Mooney
2020-08-04 16:35 ` Cornelia Huck
2020-08-05 2:22 ` Jason Wang
2020-08-05 2:16 ` Yan Zhao
2020-08-05 2:41 ` Jason Wang
2020-08-05 7:56 ` Jiri Pirko
2020-08-05 8:02 ` Jason Wang
2020-08-05 9:33 ` Yan Zhao
2020-08-05 10:53 ` Jiri Pirko
2020-08-05 11:35 ` Sean Mooney
2020-08-07 11:59 ` Cornelia Huck
2020-08-13 15:33 ` Cornelia Huck
2020-08-13 19:02 ` Eric Farman
2020-08-17 6:38 ` Cornelia Huck
2020-08-10 7:46 ` Yan Zhao
2020-08-13 4:24 ` Jason Wang
2020-08-14 5:16 ` Yan Zhao
2020-08-14 12:30 ` Sean Mooney
2020-08-17 1:52 ` Yan Zhao
2020-08-18 3:24 ` Jason Wang
2020-08-18 8:55 ` Daniel P. Berrangé [this message]
2020-08-18 9:06 ` Cornelia Huck
2020-08-18 9:24 ` Daniel P. Berrangé
2020-08-18 9:38 ` Cornelia Huck
[not found] ` <3a073222-dcfe-c02d-198b-29f6a507b2e1@redhat.com>
2020-08-18 9:16 ` Daniel P. Berrangé
2020-08-18 9:36 ` Cornelia Huck
2020-08-18 9:39 ` Parav Pandit
2020-08-19 3:30 ` Yan Zhao
2020-08-19 5:58 ` Parav Pandit
2020-08-19 9:41 ` Jason Wang
2020-08-19 6:57 ` [ovirt-devel] " Jason Wang
2020-08-19 6:59 ` Yan Zhao
2020-08-19 7:39 ` Jason Wang
2020-08-19 8:13 ` Yan Zhao
2020-08-19 9:28 ` Jason Wang
2020-08-20 12:27 ` Cornelia Huck
2020-08-21 3:14 ` Jason Wang
2020-08-21 14:52 ` Cornelia Huck
2020-08-31 3:07 ` Jason Wang
2020-08-19 17:50 ` Alex Williamson
2020-08-20 0:18 ` Yan Zhao
2020-08-20 3:13 ` Alex Williamson
2020-08-20 3:09 ` Yan Zhao
2020-08-19 2:54 ` Jason Wang
2020-08-20 0:39 ` Yan Zhao
2020-08-20 1:29 ` Sean Mooney
2020-08-20 4:01 ` Yan Zhao
2020-08-20 5:16 ` Sean Mooney
2020-08-20 6:27 ` Yan Zhao
2020-08-20 13:24 ` Sean Mooney
2020-08-26 8:54 ` Yan Zhao
2020-08-20 3:22 ` Alex Williamson
2020-08-20 3:16 ` Yan Zhao
2020-08-25 14:39 ` Cornelia Huck
2020-08-26 6:41 ` Yan Zhao
2020-08-28 13:47 ` Cornelia Huck
2020-08-28 14:04 ` Sean Mooney
2020-08-31 4:43 ` Yan Zhao
2020-09-08 14:41 ` Cornelia Huck
2020-09-09 2:13 ` Yan Zhao
2020-09-10 12:38 ` Cornelia Huck
2020-09-10 12:50 ` Sean Mooney
2020-09-10 18:02 ` Alex Williamson
2020-09-11 0:56 ` Yan Zhao
2020-09-11 10:08 ` Cornelia Huck
2020-09-11 10:18 ` Tian, Kevin
2020-09-11 16:51 ` Alex Williamson
2020-09-14 13:48 ` Zeng, Xin
2020-09-14 14:44 ` Alex Williamson
2020-09-09 5:37 ` Yan Zhao
2020-08-31 2:23 ` Yan Zhao
2020-08-19 2:38 ` Jason Wang
2020-08-18 9:32 ` Parav Pandit
2020-08-19 2:45 ` Jason Wang
2020-08-19 5:26 ` Parav Pandit
2020-08-19 6:48 ` Jason Wang
2020-08-19 6:53 ` Parav Pandit
2020-07-29 19:05 ` Dr. David Alan Gilbert
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