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From: Christoph Hellwig <hch@lst.de>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jason Gunthorpe <jgg@nvidia.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Kirti Wankhede <kwankhede@nvidia.com>
Cc: David Airlie <airlied@linux.ie>,
	Tony Krowiak <akrowiak@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>, Daniel Vetter <daniel@ffwll.ch>,
	dri-devel@lists.freedesktop.org,
	Vasily Gorbik <gor@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	intel-gfx@lists.freedesktop.org,
	Jani Nikula <jani.nikula@linux.intel.com>,
	Jason Herne <jjherne@linux.ibm.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	kvm@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-s390@vger.kernel.org, Halil Pasic <pasic@linux.ibm.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>
Subject: Allow mdev drivers to directly create the vfio_device (v4)
Date: Thu, 17 Jun 2021 16:22:08 +0200	[thread overview]
Message-ID: <20210617142218.1877096-1-hch@lst.de> (raw)

This is my alternative take on this series from Jason:

https://lore.kernel.org/dri-devel/87czsszi9i.fsf@redhat.com/T/

The mdev/vfio parts are exactly the same, but this solves the driver core
changes for the direct probing without the in/out flag that Greg hated,
which cause a little more work, but probably make the result better.

Original decription from Jason below:

The mdev bus's core part for managing the lifecycle of devices is mostly
as one would expect for a driver core bus subsystem.

However instead of having a normal 'struct device_driver' and binding the
actual mdev drivers through the standard driver core mechanisms it open
codes this with the struct mdev_parent_ops and provides a single driver
that shims between the VFIO core's struct vfio_device and the actual
device driver.

Instead, allow mdev drivers implement an actual struct mdev_driver and
directly call vfio_register_group_dev() in the probe() function for the
mdev. Arrange to bind the created mdev_device to the mdev_driver that is
provided by the end driver.

The actual execution flow doesn't change much, eg what was
parent_ops->create is now device_driver->probe and it is called at almost
the exact same time - except under the normal control of the driver core.

Ultimately converting all the drivers unlocks a fair number of additional
VFIO simplifications and cleanups.

Changes since v3:
 - minor cleanup to avoid the probe_ret variable in really_probe entirely
 - use a saner name for a variable in mdev-mtty
 - use a better driver name in mdev-mtty
 - update the documentation to match the new interface

Changes since v2:
 - avoid warning spam for successful probes
 - improve the probe_count protection

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jason Gunthorpe <jgg@nvidia.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Kirti Wankhede <kwankhede@nvidia.com>
Cc: Tony Krowiak <akrowiak@linux.ibm.com>,
	Jason Herne <jjherne@linux.ibm.com>,
	kvm@vger.kernel.org, Vasily Gorbik <gor@linux.ibm.com>,
	Jonathan Corbet <corbet@lwn.net>, David Airlie <airlied@linux.ie>,
	linux-s390@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
	Cornelia Huck <cohuck@redhat.com>,
	linux-doc@vger.kernel.org, dri-devel@lists.freedesktop.org,
	Halil Pasic <pasic@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	intel-gfx@lists.freedesktop.org
Subject: [Intel-gfx] Allow mdev drivers to directly create the vfio_device (v4)
Date: Thu, 17 Jun 2021 16:22:08 +0200	[thread overview]
Message-ID: <20210617142218.1877096-1-hch@lst.de> (raw)

This is my alternative take on this series from Jason:

https://lore.kernel.org/dri-devel/87czsszi9i.fsf@redhat.com/T/

The mdev/vfio parts are exactly the same, but this solves the driver core
changes for the direct probing without the in/out flag that Greg hated,
which cause a little more work, but probably make the result better.

Original decription from Jason below:

The mdev bus's core part for managing the lifecycle of devices is mostly
as one would expect for a driver core bus subsystem.

However instead of having a normal 'struct device_driver' and binding the
actual mdev drivers through the standard driver core mechanisms it open
codes this with the struct mdev_parent_ops and provides a single driver
that shims between the VFIO core's struct vfio_device and the actual
device driver.

Instead, allow mdev drivers implement an actual struct mdev_driver and
directly call vfio_register_group_dev() in the probe() function for the
mdev. Arrange to bind the created mdev_device to the mdev_driver that is
provided by the end driver.

The actual execution flow doesn't change much, eg what was
parent_ops->create is now device_driver->probe and it is called at almost
the exact same time - except under the normal control of the driver core.

Ultimately converting all the drivers unlocks a fair number of additional
VFIO simplifications and cleanups.

Changes since v3:
 - minor cleanup to avoid the probe_ret variable in really_probe entirely
 - use a saner name for a variable in mdev-mtty
 - use a better driver name in mdev-mtty
 - update the documentation to match the new interface

Changes since v2:
 - avoid warning spam for successful probes
 - improve the probe_count protection
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

             reply	other threads:[~2021-06-17 14:23 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-17 14:22 Christoph Hellwig [this message]
2021-06-17 14:22 ` [Intel-gfx] Allow mdev drivers to directly create the vfio_device (v4) Christoph Hellwig
2021-06-17 14:22 ` [PATCH 01/10] driver core: Pull required checks into driver_probe_device() Christoph Hellwig
2021-06-17 14:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-17 14:22 ` [PATCH 02/10] driver core: Better distinguish probe errors in really_probe Christoph Hellwig
2021-06-17 14:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-17 14:22 ` [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind Christoph Hellwig
2021-06-17 14:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-17 14:22 ` [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during " Christoph Hellwig
2021-06-17 14:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-17 14:22 ` [PATCH 05/10] driver core: Export device_driver_attach() Christoph Hellwig
2021-06-17 14:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-17 14:22 ` [PATCH 06/10] vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE Christoph Hellwig
2021-06-17 14:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-17 14:22 ` [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Christoph Hellwig
2021-06-17 14:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-17 14:22 ` [PATCH 08/10] vfio/mtty: Convert to use vfio_register_group_dev() Christoph Hellwig
2021-06-17 14:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-17 14:22 ` [PATCH 09/10] vfio/mdpy: " Christoph Hellwig
2021-06-17 14:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-17 14:22 ` [PATCH 10/10] vfio/mbochs: " Christoph Hellwig
2021-06-17 14:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-17 14:47 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [01/10] driver core: Pull required checks into driver_probe_device() Patchwork
2021-06-17 15:16 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-06-17 17:12 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2021-06-23  0:05 ` Allow mdev drivers to directly create the vfio_device (v4) Jason Gunthorpe
2021-06-23  0:05   ` [Intel-gfx] " Jason Gunthorpe
2021-06-23  0:05   ` Jason Gunthorpe
2021-06-23  1:21   ` Alex Williamson
2021-06-23  1:21     ` [Intel-gfx] " Alex Williamson
2021-06-23  1:21     ` Alex Williamson

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