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From: Jason Gunthorpe <jgg@nvidia.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Joerg Roedel <joro@8bytes.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Christoph Hellwig <hch@infradead.org>,
	Kevin Tian <kevin.tian@intel.com>,
	Ashok Raj <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Dan Williams <dan.j.williams@intel.com>,
	rafael@kernel.org, Diana Craciun <diana.craciun@oss.nxp.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Eric Auger <eric.auger@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
	Jacob jun Pan <jacob.jun.pan@intel.com>,
	Chaitanya Kulkarni <kch@nvidia.com>,
	Stuart Yoder <stuyoder@gmail.com>,
	Laurentiu Tudor <laurentiu.tudor@nxp.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Li Yang <leoyang.li@nxp.com>, Dmitry Osipenko <digetx@gmail.com>,
	iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 03/13] PCI: pci_stub: Suppress kernel DMA ownership auto-claiming
Date: Thu, 30 Dec 2021 20:40:19 -0400	[thread overview]
Message-ID: <20211231004019.GH1779224@nvidia.com> (raw)
In-Reply-To: <20211230222414.GA1805873@bhelgaas>

On Thu, Dec 30, 2021 at 04:24:14PM -0600, Bjorn Helgaas wrote:

> I was speculating that maybe the DMA ownership claiming must be done
> *before* the driver's .probe() method?  

This is correct.

> If DMA ownership could be claimed by the .probe() method, we
> wouldn't need the new flag in struct device_driver.

The other requirement is that every existing driver must claim
ownership, so pushing this into the device driver's probe op would
require revising almost every driver in Linux...

In effect the new flag indicates if the driver will do the DMA
ownership claim in it's probe, or should use the default claim the
core code does.

In almost every case a driver should do a claim. A driver like
pci-stub, or a bridge, that doesn't actually operate MMIO on the
device would be the exception.

Jason

  reply	other threads:[~2021-12-31  0:40 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-17  6:36 [PATCH v4 00/13] Fix BUG_ON in vfio_iommu_group_notifier() Lu Baolu
2021-12-17  6:36 ` [PATCH v4 01/13] iommu: Add device dma ownership set/release interfaces Lu Baolu
2021-12-17  6:36 ` [PATCH v4 02/13] driver core: Set DMA ownership during driver bind/unbind Lu Baolu
2021-12-22 12:47   ` Greg Kroah-Hartman
2021-12-22 17:52     ` Jason Gunthorpe
2021-12-23  2:08     ` Lu Baolu
2021-12-23  3:02     ` Lu Baolu
2021-12-23  7:13       ` Greg Kroah-Hartman
2021-12-23  7:23         ` Lu Baolu
2021-12-31  0:36           ` Jason Gunthorpe
2021-12-17  6:36 ` [PATCH v4 03/13] PCI: pci_stub: Suppress kernel DMA ownership auto-claiming Lu Baolu
2021-12-29 20:42   ` Bjorn Helgaas
2021-12-30  5:34     ` Lu Baolu
2021-12-30 22:24       ` Bjorn Helgaas
2021-12-31  0:40         ` Jason Gunthorpe [this message]
2021-12-31  1:10           ` Lu Baolu
2021-12-31  1:58             ` Lu Baolu
2022-01-03 19:53             ` Jason Gunthorpe
2022-01-04  1:54               ` Lu Baolu
2021-12-31  1:06         ` Lu Baolu
2021-12-17  6:36 ` [PATCH v4 04/13] PCI: portdrv: " Lu Baolu
2021-12-29 21:16   ` Bjorn Helgaas
2021-12-30  5:49     ` Lu Baolu
2021-12-17  6:37 ` [PATCH v4 05/13] iommu: Add security context management for assigned devices Lu Baolu
2021-12-17  6:37 ` [PATCH v4 06/13] iommu: Expose group variants of dma ownership interfaces Lu Baolu
2021-12-17  6:37 ` [PATCH v4 07/13] iommu: Add iommu_at[de]tach_device_shared() for multi-device groups Lu Baolu
2021-12-21 16:50   ` Robin Murphy
2021-12-21 18:46     ` Jason Gunthorpe
2021-12-22  4:22       ` Lu Baolu
2021-12-22  4:25         ` Lu Baolu
2021-12-22 20:26       ` Robin Murphy
2021-12-23  0:57         ` Jason Gunthorpe
2021-12-23  5:53           ` Lu Baolu
2021-12-23 14:03             ` Jason Gunthorpe
2021-12-24  1:30               ` Lu Baolu
2021-12-24  2:50                 ` Jason Gunthorpe
2021-12-24  6:44                   ` Lu Baolu
2022-01-04  1:53                   ` Lu Baolu
2021-12-24  3:19         ` Lu Baolu
2021-12-24 14:24           ` Jason Gunthorpe
2021-12-17  6:37 ` [PATCH v4 08/13] vfio: Set DMA USER ownership for VFIO devices Lu Baolu
2021-12-17  6:37 ` [PATCH v4 09/13] vfio: Remove use of vfio_group_viable() Lu Baolu
2021-12-17  6:37 ` [PATCH v4 10/13] vfio: Delete the unbound_list Lu Baolu
2021-12-17  6:37 ` [PATCH v4 11/13] vfio: Remove iommu group notifier Lu Baolu
2021-12-17  6:37 ` [PATCH v4 12/13] iommu: Remove iommu group changes notifier Lu Baolu
2021-12-17  6:37 ` [PATCH v4 13/13] drm/tegra: Use the iommu dma_owner mechanism Lu Baolu
2022-01-04  5:23 ` [PATCH v4 00/13] Fix BUG_ON in vfio_iommu_group_notifier() Lu Baolu

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