From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Stuart Yoder <stuyoder@gmail.com>,
rafael@kernel.org, David Airlie <airlied@linux.ie>,
linux-pci@vger.kernel.org,
Thierry Reding <thierry.reding@gmail.com>,
Diana Craciun <diana.craciun@oss.nxp.com>,
Dmitry Osipenko <digetx@gmail.com>, Will Deacon <will@kernel.org>,
Ashok Raj <ashok.raj@intel.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Christoph Hellwig <hch@infradead.org>,
Kevin Tian <kevin.tian@intel.com>,
Chaitanya Kulkarni <kch@nvidia.com>,
Alex Williamson <alex.williamson@redhat.com>,
kvm@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
Dan Williams <dan.j.williams@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Cornelia Huck <cohuck@redhat.com>,
linux-kernel@vger.kernel.org, Li Yang <leoyang.li@nxp.com>,
iommu@lists.linux-foundation.org,
Jacob jun Pan <jacob.jun.pan@intel.com>,
Daniel Vetter <daniel@ffwll.ch>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v4 07/13] iommu: Add iommu_at[de]tach_device_shared() for multi-device groups
Date: Tue, 4 Jan 2022 09:53:47 +0800 [thread overview]
Message-ID: <1a22fecf-9cba-76f8-7dc4-88a56b2457cd@linux.intel.com> (raw)
In-Reply-To: <20211224025036.GD1779224@nvidia.com>
On 12/24/21 10:50 AM, Jason Gunthorpe wrote:
>>> We don't need _USER anymore because iommu_group_set_dma_owner() always
>>> does detatch, and iommu_replace_group_domain() avoids ever reassigning
>>> default_domain. The sepecial USER behavior falls out automatically.
>> This means we will grow more group-centric interfaces. My understanding
>> is the opposite that we should hide the concept of group in IOMMU
>> subsystem, and the device drivers only faces device specific interfaces.
> Ideally group interfaces would be reduced, but in this case VFIO needs
> the group. It has sort of a fundamental problem with its uAPI that
> expects the container is fully setup with a domain at the moment the
> group is attached. So deferring domain setup to when the device is
> available becomes a user visible artifact - and if this is important
> or not is a whole research question that isn't really that important
> for this series.
>
> We also can't just pull a device out of thin air, a device that hasn't
> been probed() hasn't even had dma_configure called! Let alone the
> lifetime and locking problems with that kind of idea.
>
> So.. leaving it as a group interface makes the most sense,
> particularly for this series which is really about fixing the sharing
> model in the iommu core and deleting the BUG_ONs.
I feel it makes more sense if we leave the attach_device/group
refactoring patches into a separated series. I will come up with this
new series so that people can review and comment on the real code.
Best regards,
baolu
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next prev parent reply other threads:[~2022-01-04 1:54 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 via iommu
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 via iommu
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 via iommu
2021-12-31 1:10 ` Lu Baolu
2021-12-31 1:58 ` Lu Baolu
2022-01-03 19:53 ` Jason Gunthorpe via iommu
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 via iommu
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 via iommu
2021-12-23 5:53 ` Lu Baolu
2021-12-23 14:03 ` Jason Gunthorpe via iommu
2021-12-24 1:30 ` Lu Baolu
2021-12-24 2:50 ` Jason Gunthorpe via iommu
2021-12-24 6:44 ` Lu Baolu
2022-01-04 1:53 ` Lu Baolu [this message]
2021-12-24 3:19 ` Lu Baolu
2021-12-24 14:24 ` Jason Gunthorpe via iommu
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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