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Linus Torvalds 60b8d4d492 - Change the SEV host code handling of when SNP gets enabled in order to allow
the machine to claim SNP-related resources only when SNP guests are really
   going to be launched. The user requests this by loading the ccp module and
   thus it controls when SNP initialization is done
 
   So export an API which module code can call and do the necessary SNP setup
   only when really needed
 
 - Drop an unnecessary write-back and invalidate operation that was being
   performed too early, since the ccp driver already issues its own at the
   correct point in the initialization sequence
 
 — Drop the hotplug callbacks for enabling SNP on newly onlined CPUs, which
   were both architecturally unsound (the firmware rejects initialization if any
   CPU lacks the required configuration) and buggy (the MFDM SYSCFG MSR bit was
   not being set)
 
 - Code refactoring and cleanups to accomplish the above
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Merge tag 'x86_sev_for_v7.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SEV updates from Borislav Petkov:

 - Change the SEV host code handling of when SNP gets enabled in order
   to allow the machine to claim SNP-related resources only when SNP
   guests are really going to be launched. The user requests this by
   loading the ccp module and thus it controls when SNP initialization
   is done

   So export an API which module code can call and do the necessary SNP
   setup only when really needed

 - Drop an unnecessary write-back and invalidate operation that was
   being performed too early, since the ccp driver already issues its
   own at the correct point in the initialization sequence

 - Drop the hotplug callbacks for enabling SNP on newly onlined CPUs,
   which were both architecturally unsound (the firmware rejects
   initialization if any CPU lacks the required configuration) and buggy
   (the MFDM SYSCFG MSR bit was not being set)

 - Code refactoring and cleanups to accomplish the above

* tag 'x86_sev_for_v7.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  crypto/ccp: Update HV_FIXED page states to allow freeing of memory
  crypto/ccp: Implement SNP x86 shutdown
  x86/sev, crypto/ccp: Move HSAVE_PA setup to arch/x86/
  x86/sev, crypto/ccp: Move SNP init to ccp driver
  x86/sev: Create snp_shutdown()
  x86/sev: Create snp_prepare()
  x86/sev: Create a function to clear/zero the RMP
  x86/sev: Rename SNP_FEATURES_PRESENT to SNP_FEATURES_IMPL
  x86/virt/sev: Keep the RMP table bookkeeping area mapped
  x86/virt/sev: Drop WBINVD before setting MSR_AMD64_SYSCFG_SNP_EN
  x86/virt/sev: Drop support for SNP hotplug
2026-04-14 15:20:54 -07:00
arch - Change the SEV host code handling of when SNP gets enabled in order to allow 2026-04-14 15:20:54 -07:00
block for-7.1/block-20260411 2026-04-13 15:51:31 -07:00
certs Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
crypto CRC updates for 7.1 2026-04-13 17:36:04 -07:00
Documentation - We made the FRED support an opt-in initially out of fear of it breaking 2026-04-14 14:50:51 -07:00
drivers - Change the SEV host code handling of when SNP gets enabled in order to allow 2026-04-14 15:20:54 -07:00
fs — Add return value descriptions to several internal functions, addressing 2026-04-14 14:46:37 -07:00
include - Change the SEV host code handling of when SNP gets enabled in order to allow 2026-04-14 15:20:54 -07:00
init Scheduler changes for v7.1: 2026-04-14 13:33:36 -07:00
io_uring for-7.1/io_uring-20260411 2026-04-13 16:22:30 -07:00
ipc Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kernel Scheduler changes for v7.1: 2026-04-14 13:33:36 -07:00
lib Locking updates for v7.1: 2026-04-14 12:36:25 -07:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
mm for-7.1/block-20260411 2026-04-13 15:51:31 -07:00
net Crypto library updates for 7.1 2026-04-13 17:31:39 -07:00
rust Locking updates for v7.1: 2026-04-14 12:36:25 -07:00
samples Driver core changes for 7.1-rc1 2026-04-13 19:03:11 -07:00
scripts objtool updates for v7.1: 2026-04-14 13:00:04 -07:00
security Crypto library updates for 7.1 2026-04-13 17:31:39 -07:00
sound - Complete LASS enabling: deal with vsyscall and EFI 2026-04-14 14:24:45 -07:00
tools - Complete LASS enabling: deal with vsyscall and EFI 2026-04-14 14:24:45 -07:00
usr kbuild: uapi: also test UAPI headers against C++ compilers 2026-03-25 13:24:42 +01:00
virt vfs-7.1-rc1.bh.metadata 2026-04-13 12:46:42 -07:00
.clang-format Devicetree updates for v7.0: 2026-02-11 18:27:08 -08:00
.clippy.toml rust: bump Clippy's MSRV and clean incompatible_msrv allows 2026-04-07 09:51:39 +02:00
.cocciconfig
.editorconfig editorconfig: add rst extension 2026-01-26 19:07:09 -08:00
.get_maintainer.ignore .get_maintainer.ignore: add myself 2026-04-02 16:48:25 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rust: provide an option to inline C helpers into Rust 2026-03-30 02:03:52 +02:00
.mailmap MAINTAINERS, mailmap: Change Ulf Hansson's email 2026-04-07 14:17:48 +02:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml
COPYING
CREDITS MAINTAINERS: remove Thomas Falcon from IBM ibmvnic 2026-03-05 07:35:45 -08:00
Kbuild checksyscalls: move instance functionality into generic code 2026-04-05 09:21:32 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS — Reference the tip tree maintainer handbook directly from the relevant 2026-04-14 15:15:08 -07:00
Makefile Kbuild/Kconfig updates for 7.1 2026-04-14 09:18:40 -07:00
README docs: add AI Coding Assistants documentation 2026-01-06 14:55:06 -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