kernel/linux.git/Documentation/x86, branch master

docs: move x86 documentation into Documentation/arch/

2023-03-30T18:58:51+00:00

Move the x86 documentation under Documentation/arch/ as a way of cleaning up the top-level directory and making the structure of our docs more closely match the structure of the source directories it describes. All in-kernel references to the old paths have been updated. Acked-by: Dave Hansen Cc: linux-arch@vger.kernel.org Cc: x86@kernel.org Cc: Borislav Petkov Cc: Thomas Gleixner Link: https://lore.kernel.org/lkml/20230315211523.108836-1-corbet@lwn.net/ Signed-off-by: Jonathan Corbet

Documentation/x86: Update split lock documentation

2023-03-23T18:02:35+00:00

commit b041b525dab9 ("x86/split_lock: Make life miserable for split lockers") added a delay and serialization of split locks. Commit 727209376f49 ("x86/split_lock: Add sysctl to control the misery mode") provided a sysctl to turn off the misery. Update the split lock documentation to describe the current state of the code. Signed-off-by: Tony Luck Link: https://lore.kernel.org/r/20230315225722.104607-1-tony.luck@intel.com Signed-off-by: Jonathan Corbet

Merge tag 'docs-6.3' of git://git.lwn.net/linux

2023-02-22T20:00:20+00:00

Pull documentation updates from Jonathan Corbet: "It has been a moderately calm cycle for documentation; the significant changes include: - Some significant additions to the memory-management documentation - Some improvements to navigation in the HTML-rendered docs - More Spanish and Chinese translations ... and the usual set of typo fixes and such" * tag 'docs-6.3' of git://git.lwn.net/linux: (68 commits) Documentation/watchdog/hpwdt: Fix Format Documentation/watchdog/hpwdt: Fix Reference Documentation: core-api: padata: correct spelling docs/mm: Physical Memory: correct spelling in reference to CONFIG_PAGE_EXTENSION docs: Use HTML comments for the kernel-toc SPDX line docs: Add more information to the HTML sidebar Documentation: KVM: Update AMD memory encryption link printk: Document that CONFIG_BOOT_PRINTK_DELAY required for boot_delay= Documentation: userspace-api: correct spelling Documentation: sparc: correct spelling Documentation: driver-api: correct spelling Documentation: admin-guide: correct spelling docs: add workload-tracing document to admin-guide docs/admin-guide/mm: remove useless markup docs/mm: remove useless markup docs/mm: Physical Memory: remove useless markup docs/sp_SP: Add process magic-number translation docs: ftrace: always use canonical ftrace path Doc/damon: fix the data path error dma-buf: Add "dma-buf" to title of documentation ...

Merge tag 'x86_cache_for_v6.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-02-21T16:38:45+00:00

Pull x86 resource control updates from Borislav Petkov: - Add support for a new AMD feature called slow memory bandwidth allocation. Its goal is to control resource allocation in external slow memory which is connected to the machine like for example through CXL devices, accelerators etc * tag 'x86_cache_for_v6.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/resctrl: Fix a silly -Wunused-but-set-variable warning Documentation/x86: Update resctrl.rst for new features x86/resctrl: Add interface to write mbm_local_bytes_config x86/resctrl: Add interface to write mbm_total_bytes_config x86/resctrl: Add interface to read mbm_local_bytes_config x86/resctrl: Add interface to read mbm_total_bytes_config x86/resctrl: Support monitor configuration x86/resctrl: Add __init attribute to rdt_get_mon_l3_config() x86/resctrl: Detect and configure Slow Memory Bandwidth Allocation x86/resctrl: Include new features in command line options x86/cpufeatures: Add Bandwidth Monitoring Event Configuration feature flag x86/resctrl: Add a new resource type RDT_RESOURCE_SMBA x86/cpufeatures: Add Slow Memory Bandwidth Allocation feature flag x86/resctrl: Replace smp_call_function_many() with on_each_cpu_mask()

docs: ftrace: always use canonical ftrace path

2023-01-31T21:02:30+00:00

The canonical location for the tracefs filesystem is at /sys/kernel/tracing. But, from Documentation/trace/ftrace.rst: Before 4.1, all ftrace tracing control files were within the debugfs file system, which is typically located at /sys/kernel/debug/tracing. For backward compatibility, when mounting the debugfs file system, the tracefs file system will be automatically mounted at: /sys/kernel/debug/tracing Many parts of Documentation still reference this older debugfs path, so let's update them to avoid confusion. Signed-off-by: Ross Zwisler Reviewed-by: Steven Rostedt (Google) Link: https://lore.kernel.org/r/20230125213251.2013791-1-zwisler@google.com Signed-off-by: Jonathan Corbet

Documentation/x86: Update resctrl.rst for new features

2023-01-23T16:40:37+00:00

Update the documentation for the new features: 1. Slow Memory Bandwidth allocation (SMBA). With this feature, the QOS enforcement policies can be applied to the external slow memory connected to the host. QOS enforcement is accomplished by assigning a Class Of Service (COS) to a processor and specifying allocations or limits for that COS for each resource to be allocated. 2. Bandwidth Monitoring Event Configuration (BMEC). The bandwidth monitoring events mbm_total_bytes and mbm_local_bytes are set to count all the total and local reads/writes respectively. With the introduction of slow memory, the two counters are not enough to count all the different types of memory events. With the feature BMEC, the users have the option to configure mbm_total_bytes and mbm_local_bytes to count the specific type of events. Also add configuration instructions with examples. Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/r/20230113152039.770054-14-babu.moger@amd.com

x86/sev: Add SEV-SNP guest feature negotiation support

2023-01-19T16:29:58+00:00

The hypervisor can enable various new features (SEV_FEATURES[1:63]) and start a SNP guest. Some of these features need guest side implementation. If any of these features are enabled without it, the behavior of the SNP guest will be undefined. It may fail booting in a non-obvious way making it difficult to debug. Instead of allowing the guest to continue and have it fail randomly later, detect this early and fail gracefully. The SEV_STATUS MSR indicates features which the hypervisor has enabled. While booting, SNP guests should ascertain that all the enabled features have guest side implementation. In case a feature is not implemented in the guest, the guest terminates booting with GHCB protocol Non-Automatic Exit(NAE) termination request event, see "SEV-ES Guest-Hypervisor Communication Block Standardization" document (currently at https://developer.amd.com/wp-content/resources/56421.pdf), section "Termination Request". Populate SW_EXITINFO2 with mask of unsupported features that the hypervisor can easily report to the user. More details in the AMD64 APM Vol 2, Section "SEV_STATUS MSR". [ bp: - Massage. - Move snp_check_features() call to C code. Note: the CC:stable@ aspect here is to be able to protect older, stable kernels when running on newer hypervisors. Or not "running" but fail reliably and in a well-defined manner instead of randomly. ] Fixes: cbd3d4f7c4e5 ("x86/sev: Check SEV-SNP features support") Signed-off-by: Nikunj A Dadhania Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Tom Lendacky Cc: Link: https://lore.kernel.org/r/20230118061943.534309-1-nikunj@amd.com

Documentation: x86: fix typo in x86_64/mm.rst

2023-01-02T23:39:20+00:00

change "64Gb" to "64GB". Signed-off-by: Wang Yong Link: https://lore.kernel.org/r/20221228100141.382325-1-yongw.kernel@gmail.com Signed-off-by: Jonathan Corbet

Merge tag 'x86_tdx_for_6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-12-12T22:27:49+00:00

Pull x86 tdx updates from Dave Hansen: "This includes a single chunk of new functionality for TDX guests which allows them to talk to the trusted TDX module software and obtain an attestation report. This report can then be used to prove the trustworthiness of the guest to a third party and get access to things like storage encryption keys" * tag 'x86_tdx_for_6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: selftests/tdx: Test TDX attestation GetReport support virt: Add TDX guest driver x86/tdx: Add a wrapper to get TDREPORT0 from the TDX Module

virt: Add TDX guest driver

2022-11-17T19:04:23+00:00

TDX guest driver exposes IOCTL interfaces to service TDX guest user-specific requests. Currently, it is only used to allow the user to get the TDREPORT to support TDX attestation. Details about the TDX attestation process are documented in Documentation/x86/tdx.rst, and the IOCTL details are documented in Documentation/virt/coco/tdx-guest.rst. Operations like getting TDREPORT involves sending a blob of data as input and getting another blob of data as output. It was considered to use a sysfs interface for this, but it doesn't fit well into the standard sysfs model for configuring values. It would be possible to do read/write on files, but it would need multiple file descriptors, which would be somewhat messy. IOCTLs seem to be the best fitting and simplest model for this use case. The AMD sev-guest driver also uses the IOCTL interface to support attestation. [Bagas Sanjaya: Ack is for documentation portion] Signed-off-by: Kuppuswamy Sathyanarayanan Signed-off-by: Dave Hansen Reviewed-by: Bagas Sanjaya Reviewed-by: Tony Luck Reviewed-by: Mika Westerberg Acked-by: Kai Huang Acked-by: Kirill A. Shutemov Acked-by: Wander Lairson Costa Link: https://lore.kernel.org/all/20221116223820.819090-3-sathyanarayanan.kuppuswamy%40linux.intel.com