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authorLinus Torvalds <torvalds@linux-foundation.org>2020-12-17 00:58:47 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-17 00:58:47 +0300
commit19778dd504b5ff5c3c1283aa3da7a56f34c2c3b0 (patch)
tree6e673f8b95663a7c56726984859ac3cf191df5c0 /Documentation/ABI
parent007c74e16c1aac9f5c93b372a054f7f11ede8628 (diff)
parent5ae9a046a452d60b6a6c076f6df7e3f8e34f918f (diff)
downloadlinux-19778dd504b5ff5c3c1283aa3da7a56f34c2c3b0.tar.xz
Merge tag 'iommu-updates-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull IOMMU updates from Will Deacon: "There's a good mixture of improvements to the core code and driver changes across the board. One thing worth pointing out is that this includes a quirk to work around behaviour in the i915 driver (see 65f746e8285f ("iommu: Add quirk for Intel graphic devices in map_sg")), which otherwise interacts badly with the conversion of the intel IOMMU driver over to the DMA-IOMMU APU but has being fixed properly in the DRM tree. We'll revert the quirk later this cycle once we've confirmed that things don't fall apart without it. Summary: - IOVA allocation optimisations and removal of unused code - Introduction of DOMAIN_ATTR_IO_PGTABLE_CFG for parameterising the page-table of an IOMMU domain - Support for changing the default domain type in sysfs - Optimisation to the way in which identity-mapped regions are created - Driver updates: * Arm SMMU updates, including continued work on Shared Virtual Memory * Tegra SMMU updates, including support for PCI devices * Intel VT-D updates, including conversion to the IOMMU-DMA API - Cleanup, kerneldoc and minor refactoring" * tag 'iommu-updates-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (50 commits) iommu/amd: Add sanity check for interrupt remapping table length macros dma-iommu: remove __iommu_dma_mmap iommu/io-pgtable: Remove tlb_flush_leaf iommu: Stop exporting free_iova_mem() iommu: Stop exporting alloc_iova_mem() iommu: Delete split_and_remove_iova() iommu/io-pgtable-arm: Remove unused 'level' parameter from iopte_type() macro iommu: Defer the early return in arm_(v7s/lpae)_map iommu: Improve the performance for direct_mapping iommu: avoid taking iova_rbtree_lock twice iommu/vt-d: Avoid GFP_ATOMIC where it is not needed iommu/vt-d: Remove set but not used variable iommu: return error code when it can't get group iommu: Fix htmldocs warnings in sysfs-kernel-iommu_groups iommu: arm-smmu-impl: Add a space before open parenthesis iommu: arm-smmu-impl: Use table to list QCOM implementations iommu/arm-smmu: Move non-strict mode to use io_pgtable_domain_attr iommu/arm-smmu: Add support for pagetable config domain attribute iommu: Document usage of "/sys/kernel/iommu_groups/<grp_id>/type" file iommu: Take lock before reading iommu group default domain type ...
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/sysfs-kernel-iommu_groups30
1 files changed, 30 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-iommu_groups b/Documentation/ABI/testing/sysfs-kernel-iommu_groups
index 017f5bc3920c..0fedbb0f94e4 100644
--- a/Documentation/ABI/testing/sysfs-kernel-iommu_groups
+++ b/Documentation/ABI/testing/sysfs-kernel-iommu_groups
@@ -33,3 +33,33 @@ Description: In case an RMRR is used only by graphics or USB devices
it is now exposed as "direct-relaxable" instead of "direct".
In device assignment use case, for instance, those RMRR
are considered to be relaxable and safe.
+
+What: /sys/kernel/iommu_groups/<grp_id>/type
+Date: November 2020
+KernelVersion: v5.11
+Contact: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
+Description: /sys/kernel/iommu_groups/<grp_id>/type shows the type of default
+ domain in use by iommu for this group. See include/linux/iommu.h
+ for possible read values. A privileged user could request kernel to
+ change the group type by writing to this file. Valid write values:
+
+ ======== ======================================================
+ DMA All the DMA transactions from the device in this group
+ are translated by the iommu.
+ identity All the DMA transactions from the device in this group
+ are not translated by the iommu.
+ auto Change to the type the device was booted with.
+ ======== ======================================================
+
+ The default domain type of a group may be modified only when
+
+ - The group has only one device.
+ - The device in the group is not bound to any device driver.
+ So, the users must unbind the appropriate driver before
+ changing the default domain type.
+
+ Unbinding a device driver will take away the driver's control
+ over the device and if done on devices that host root file
+ system could lead to catastrophic effects (the users might
+ need to reboot the machine to get it to normal state). So, it's
+ expected that the users understand what they're doing.