From: Jason Gunthorpe <jgg@nvidia.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>,
Alex Williamson <alex.williamson@redhat.com>,
Christoph Hellwig <hch@infradead.org>,
Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
kvm@vger.kernel.org, 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>,
Stuart Yoder <stuyoder@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Chaitanya Kulkarni <kch@nvidia.com>,
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>
Subject: Re: [PATCH v1 1/8] iommu: Add iommu_group_replace_domain()
Date: Mon, 14 Feb 2022 08:45:18 -0400 [thread overview]
Message-ID: <20220214124518.GU4160@nvidia.com> (raw)
In-Reply-To: <43f2fc07-19ea-53a4-af86-a9192a950c96@arm.com>
On Mon, Feb 14, 2022 at 12:09:36PM +0000, Robin Murphy wrote:
> On 2022-01-06 02:20, Lu Baolu wrote:
> > Expose an interface to replace the domain of an iommu group for frameworks
> > like vfio which claims the ownership of the whole iommu group.
>
> But if the underlying point is the new expectation that
> iommu_{attach,detach}_device() operate on the device's whole group where
> relevant, why should we invent some special mechanism for VFIO to be
> needlessly inconsistent?
>
> I said before that it's trivial for VFIO to resolve a suitable device if it
> needs to; by now I've actually written the patch ;)
>
> https://gitlab.arm.com/linux-arm/linux-rm/-/commit/9f37d8c17c9b606abc96e1f1001c0b97c8b93ed5
Er, how does locking work there? What keeps busdev from being
concurrently unplugged? How can iommu_group_get() be safely called on
this pointer?
All of the above only works normally inside a probe/remove context
where the driver core is blocking concurrent unplug and descruction.
I think I said this last time you brought it up that lifetime was the
challenge with this idea.
Jason
next prev parent reply other threads:[~2022-02-14 12:45 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-06 2:20 [PATCH v1 0/8] Scrap iommu_attach/detach_group() interfaces Lu Baolu
2022-01-06 2:20 ` [PATCH v1 1/8] iommu: Add iommu_group_replace_domain() Lu Baolu
2022-01-06 17:06 ` Jason Gunthorpe
2022-01-07 0:26 ` Lu Baolu
2022-02-14 12:09 ` Robin Murphy
2022-02-14 12:45 ` Jason Gunthorpe [this message]
2022-02-14 14:10 ` Robin Murphy
2022-02-14 14:56 ` Jason Gunthorpe
2022-02-14 16:38 ` Robin Murphy
2022-02-14 17:25 ` Jason Gunthorpe
2022-01-06 2:20 ` [PATCH v1 2/8] vfio/type1: Use iommu_group_replace_domain() Lu Baolu
2022-01-06 2:20 ` [PATCH v1 3/8] iommu: Extend iommu_at[de]tach_device() for multi-device groups Lu Baolu
2022-01-06 17:22 ` Jason Gunthorpe
2022-01-07 1:14 ` Lu Baolu
2022-01-07 1:19 ` Jason Gunthorpe
2022-02-14 11:39 ` Joerg Roedel
2022-02-14 13:03 ` Jason Gunthorpe
2022-02-14 14:39 ` Joerg Roedel
2022-02-14 15:18 ` Robin Murphy
2022-02-14 15:46 ` Jason Gunthorpe
2022-02-15 8:58 ` Joerg Roedel
2022-02-15 13:47 ` Jason Gunthorpe
2022-02-16 6:28 ` Lu Baolu
2022-02-16 13:54 ` Jason Gunthorpe
2022-01-06 2:20 ` [PATCH v1 4/8] drm/tegra: Use iommu_attach/detatch_device() Lu Baolu
2022-01-06 2:20 ` [PATCH v1 5/8] iommu/amd: Use iommu_attach/detach_device() Lu Baolu
2022-01-06 14:33 ` Jason Gunthorpe
2022-01-07 0:23 ` Lu Baolu
2022-02-14 11:27 ` Joerg Roedel
2022-02-14 13:15 ` Jason Gunthorpe
2022-02-14 13:40 ` Joerg Roedel
2022-02-14 14:02 ` Jason Gunthorpe
2022-02-14 14:23 ` Joerg Roedel
2022-02-14 15:00 ` Jason Gunthorpe
2022-02-15 9:11 ` Joerg Roedel
2022-02-15 13:02 ` Robin Murphy
2022-02-15 14:37 ` Jason Gunthorpe
2022-01-06 2:20 ` [PATCH v1 6/8] gpu/host1x: " Lu Baolu
2022-01-06 15:35 ` Jason Gunthorpe
2022-01-07 0:35 ` Lu Baolu
2022-01-07 0:48 ` Jason Gunthorpe
2022-01-07 1:19 ` Lu Baolu
2022-01-06 2:20 ` [PATCH v1 7/8] media: staging: media: tegra-vde: " Lu Baolu
2022-01-06 2:20 ` [PATCH v1 8/8] iommu: Remove iommu_attach/detach_group() Lu Baolu
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