Linus Torvalds 4994ef0fe0 Merge tag 'iommu-updates-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux
Pull iommu updates from Joerg Roedel:
 "ARM SMMUv2:
   - Device-tree binding updates for Qualcomm Eliza, Maili, Shikra and
     IPQ9650 SoCs
   - Add support for Qualcomm SM8450
   - Numerous fixes for lifetime and ordering issues found by Sashiko in
     the Qualcomm driver

  ARM SMMUv3:
   - Fix interrupt type in device-tree binding example for NVIDIA CMDQV
   - Numerous fixes for issues identified by Sashiko in the NVIDIA CMDQV
     driver
   - Work around TLB erratum T264-SMMU-3 on Tegra264 by repeating the
     invalidation sequence
   - Add support for HAFT (hardware access flag in table entries) when
     using SVA
   - Probe for 52-bit addressing with a page size smaller than 64k
     ('DS') but don't do anything with it for now
   - Minor driver improvements (remove sort_nonatomic(), use
     readl_relaxed_poll_timeout_atomic(), fix IOPF teardown ordering)

  Intel VT-d:
   - Consolidation of complex enablement logic into a clean,
     priority-based state machine
   - Support for the DMA_REMAP_OPT_OUT flag from the VT-d v5.2
     specification
   - An update to cache_tag_flush_devtlb_psi() to use full-range
     constants instead of modifying shared variables for
     CACHE_TAG_NESTING_DEVTLB
   - A fix for the UCTP context-table slot when copying root entries
   - Fixes for several pre-existing issues reported by Sashiko
   - General code cleanup and refinement

  AMD IOMMU:
   - Add SNP page-mode-0 support, enabling passthrough, v2 DMA page
     tables and host SVA on supporting systems
   - Fix invalid PPR handling, COMPLETE_PPR responses and guest-mode
     reporting
   - Improve Southbridge IOAPIC validation and remove the dependency on
     hard-coded device IDs
   - Fix PCI-device lifetime, debugfs and diagnostic issues

  IOMMU core and IOMMUFD:
   - Restore serialization of the shared MSI-page list
   - Fix SVA-handle publication and several IOMMUFD reference and error
     path leaks
   - Return the expected zero result for invalid generic page-table
     translations
   - Allocate per-CPU IOVA magazines lazily to reduce memory use on
     large systems

  PCI ATS:
   - Make VF support checks account for the associated PF and validate
     that VF and PF Smallest Translation Unit settings agree

  Platform drivers:
   - Fix Qualcomm runtime-PM, probe unwind, fault reporting and page
     table initialization races
   - Rework Rockchip state handling and fix clock, probe and stale-fault
     handling
   - Fix smaller issues in the MSM and MediaTek drivers

  Device-tree bindings:
   - Add new Qualcomm SMMU compatibles, convert the OMAP IOMMU binding
     to YAML, and fix the Tegra264 CMDQV interrupt example

  Various smaller cleanups, documentation fixes and a Rust IOMMU
  safety/readability improvement"

* tag 'iommu-updates-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux: (93 commits)
  iommu/amd: Add SNP page mode 0 support
  iommu/amd: Fix GN bit setting in COMPLETE_PPR_REQUEST command
  iommu/amd: Rate limit INVALID_PPR_REQUEST error logging
  iommu/amd: Fix missing CMD_COMPLETE_PPR response for invalid PPR requests
  iommu/amd: Introduce PPR_TAG_LAST_PAGE() macro
  iommu/amd: Fix incorrect device ID in invalid PASID error message
  iommu/vt-d: Flush context cache with correct SID when tearing down aliases
  iommu/vt-d: Tear down scalable-mode context on probe failure
  iommu/vt-d: Fix iopf_refcount leak on RID domain replacement
  iommu/vt-d: Clear Present bit before tearing down copied context entry
  iommu/vt-d: Fix copied_tables bitmap leak on error in copy_translation_tables
  iommu/vt-d: Cache max domain ID to avoid redundant calculation
  iommu/vt-d: Support the new DMA_REMAP_OPT_OUT flag bit
  iommu/vt-d: Remove dmar_disabled
  iommu/vt-d: Remove the 'force_on' variable
  iommu/vt-d: Call dmar_can_force_on() for tboot opt-in
  iommu/vt-d: Use dmar_can_force_on() for platform opt-in
  iommu/vt-d: Consolidate dmar policy management and force_on logic
  iommu/vt-d: Remove dead code when CONFIG_INTEL_IOMMU is not set
  iommu/vt-d: Force requesting ACS when tboot is enabled
  ...
2026-08-19 12:38:26 -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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