From: Jason Gunthorpe <jgg@nvidia.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: iommu@lists.linux.dev, Joerg Roedel <joro@8bytes.org>,
Christoph Hellwig <hch@infradead.org>,
Kevin Tian <kevin.tian@intel.com>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/6] iommu: Extend changing default domain to normal group
Date: Fri, 17 Feb 2023 11:47:52 -0400 [thread overview]
Message-ID: <Y++hqGY3qg7EKZLY@nvidia.com> (raw)
In-Reply-To: <20230217094736.159005-1-baolu.lu@linux.intel.com>
On Fri, Feb 17, 2023 at 05:47:30PM +0800, Lu Baolu wrote:
> The IOMMU group sysfs interface allows users to change the default
> domain of a group. The current implementation uses device_lock() to make
> sure that the devices in the group are not bound to any driver and won't
> be bound during the process of changing the default domain. In order to
> avoid a possible deadlock caused by lock order of device_lock and
> group->mutex, it limits the functionality to singleton groups only.
>
> The recently implemented DMA ownership framework can be applied here to
> replace device_lock(). In addition, use group->mutex to ensure that the
> iommu ops of the devices is always valid during the process of changing
> default domain.
>
> With above replacement and enhancement, the device_lock() could be
> removed and the singleton-group-only limitation could be removed.
>
> The whole series is also available on github:
> https://github.com/LuBaolu/intel-iommu/commits/iommu-sysfs-default-domain-extension-v2
>
> This series is on top of below series from Robin,
> https://lore.kernel.org/linux-iommu/cover.1674753627.git.robin.murphy@arm.com/
>
> Please help to review and suggest.
Given the overall situation, I think my suggestion to use
arm_iommu_release_device() might be more short term practical.
Jason
next prev parent reply other threads:[~2023-02-17 15:48 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-17 9:47 [PATCH v2 0/6] iommu: Extend changing default domain to normal group Lu Baolu
2023-02-17 9:47 ` [PATCH v2 1/6] ARM/dma-mapping: Remove iommu_detach_device() Lu Baolu
2023-02-17 15:39 ` Jason Gunthorpe
2023-02-18 6:59 ` Baolu Lu
2023-02-18 15:58 ` Jason Gunthorpe
2023-02-20 14:21 ` Robin Murphy
2023-02-17 9:47 ` [PATCH v2 2/6] iommu: Split iommu_group_remove_device() into helpers Lu Baolu
2023-02-17 9:47 ` [PATCH v2 3/6] iommu: Same critical region for device release and removal Lu Baolu
2023-02-17 15:40 ` Jason Gunthorpe
2023-02-18 7:29 ` Baolu Lu
2023-02-21 1:13 ` Jason Gunthorpe
2023-02-17 9:47 ` [PATCH v2 4/6] iommu: Move lock from iommu_change_dev_def_domain() to its caller Lu Baolu
2023-02-17 9:47 ` [PATCH v2 5/6] iommu: Replace device_lock() with group->mutex Lu Baolu
2023-02-17 9:47 ` [PATCH v2 6/6] iommu: Cleanup iommu_change_dev_def_domain() Lu Baolu
2023-02-17 15:47 ` Jason Gunthorpe [this message]
2023-02-18 7:31 ` [PATCH v2 0/6] iommu: Extend changing default domain to normal group Baolu Lu
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