Linus Torvalds d076a8d3b9 Merge tag 'iommu-updates-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux
Pull iommu updates from Joerg Roedel:
 "Core Code:

   - Fix dma-iommu scatterlist length handling in the P2PDMA path

   - Extend the generic IOMMU page-table code with detailed gather
     support for more precise invalidations

   - Add pending-gather tracking to generic page-table invalidation
     handling

   - Add support for smaller virtual address sizes in the generic AMDv1
     page-table format, including KUnit coverage

   - Fix page-size bitmap calculation for smaller VA configurations

   - Rework Arm io-pgtable allocation/freeing to consistently use the
     iommu-pages API and address-conversion helpers

   - Add PCI ATS infrastructure for devices that require ATS, including
     always-on ATS handling for pre-CXL devices

  AMD IOMMU:

   - Fix several IOTLB invalidation details, including PDE handling,
     flush-all behavior, and command address encoding

   - Honor IVINFO[VASIZE] when deriving address limits

   - Fix premature loop termination in init_iommu_one()

   - Add Hygon family 18h model 4h IOAPIC support

   - Clean up legacy-mode handling, stale comments, dead IVMD
     exclusion-range code, and unused address-size macros

  Arm SMMU / Arm SMMU v3:

   - SMMUv2:
      - Device-tree binding updates for Qualcomm Hawi, Nord and Shikra
        SoCs
      - Constrain the clocks which can be specified for recent Qualcomm
        SoCs
      - Fix broken compatible string for Qualcomm prefetcher
        configuration an add new entry for the Glymur MDSS
      - Ensure SMMU is powered-up when writing context bank for Adreno
        client

   - SMMUv3:
      - Fix off-by-one in queue allocation retry loop
      - Enable hardware update of access/dirty bits from the SMMU
      - Re-jig command construction to use separate inline helpers for
        each command type

  Intel VT-d:

   - Add the PCI segment number to DMA fault messages

   - Improve support for non-PRI mode SVA

   - Ensure atomicity during context entry teardown

   - Fix RB-tree corruption in the probe error path

  RISC-V IOMMU:

   - Add NAPOT range invalidation support

   - Use detailed gather information for invalidation decisions

   - Compute the best stride for single invalidations

   - Advertise Svpbmt support to the generic page-table code

   - Add capability definitions and clean up command macro encoding

  VeriSilicon IOMMU:

   - Add a new VeriSilicon IOMMU driver

   - Add devicetree binding documentation and MAINTAINERS coverage

   - Add the RK3588 VeriSilicon IOMMU node

   - Apply small cleanups and warning fixes in the new driver

  Rockchip IOMMU:

   - Disable the fetch DTE time limit

  Apple DART:

   - Correct a stale CONFIG_PCIE_APPLE macro name in a comment"

* tag 'iommu-updates-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux: (66 commits)
  iommu/dma-iommu: Fix wrong scatterlist length assignment in P2PDMA path
  iommu/amd: Control INVALIDATE_IOMMU_PAGES PDE from the gather
  iommu/amd: Make CMD_INV_IOMMU_ALL_PAGES_ADDRESS match the spec
  iommu/amd: Have amd_iommu_domain_flush_pages() use last
  iommu/amd: Pass last in through to build_inv_address()
  iommu/amd: Simplify build_inv_address()
  iommu/apple-dart: correct CONFIG_PCIE_APPLE macro name in comment
  iommu/vt-d: Fix RB-tree corruption in probe error path
  iommu/vt-d: Improve IOMMU fault information
  iommu/vt-d: Remove typo from pasid_pte_config_nested()
  iommu/vt-d: Clear Present bit before tearing down scalable-mode context entry
  iommu/vt-d: Avoid WARNING in sva unbind path
  dt-bindings: arm-smmu: Correct and add constraints for Hawi, Shikra and Kaanapali
  dt-bindings: arm-smmu: Add compatible for Qualcomm Nord SoC
  iommu/amd: Don't split flush for amd_iommu_domain_flush_all()
  iommu/rockchip: disable fetch dte time limit
  iommu/arm-smmu-v3: Allow ATS to be always on
  PCI: Allow ATS to be always on for pre-CXL devices
  PCI: Add pci_ats_required() for CXL.cache capable devices
  iommu/vsi: Use list_for_each_entry()
  ...
2026-06-17 12:24:50 -07:00
2026-01-26 19:07:09 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros
* AI Coding Assistant - LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst
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