From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- Documentation/doc-guide/parse-headers.rst | 187 ++++++++++++++++++++++++++++++ 1 file changed, 187 insertions(+) create mode 100644 Documentation/doc-guide/parse-headers.rst (limited to 'Documentation/doc-guide/parse-headers.rst') diff --git a/Documentation/doc-guide/parse-headers.rst b/Documentation/doc-guide/parse-headers.rst new file mode 100644 index 000000000..a7bb01ff0 --- /dev/null +++ b/Documentation/doc-guide/parse-headers.rst @@ -0,0 +1,187 @@ +=========================== +Including uAPI header files +=========================== + +Sometimes, it is useful to include header files and C example codes in +order to describe the userspace API and to generate cross-references +between the code and the documentation. Adding cross-references for +userspace API files has an additional advantage: Sphinx will generate warnings +if a symbol is not found at the documentation. That helps to keep the +uAPI documentation in sync with the Kernel changes. +The :ref:`parse_headers.py ` provides a way to generate such +cross-references. It has to be called via Makefile, while building the +documentation. Please see ``Documentation/userspace-api/media/Makefile`` for an example +about how to use it inside the Kernel tree. + +.. _parse_headers: + +tools/docs/parse_headers.py +^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +NAME +**** + +parse_headers.py - parse a C file, in order to identify functions, structs, +enums and defines and create cross-references to a Sphinx book. + +USAGE +***** + +parse-headers.py [-h] [-d] [-t] ``FILE_IN`` ``FILE_OUT`` ``FILE_RULES`` + +SYNOPSIS +******** + +Converts a C header or source file ``FILE_IN`` into a ReStructured Text +included via ..parsed-literal block with cross-references for the +documentation files that describe the API. It accepts an optional +``FILE_RULES`` file to describe what elements will be either ignored or +be pointed to a non-default reference type/name. + +The output is written at ``FILE_OUT``. + +It is capable of identifying ``define``, ``struct``, ``typedef``, ``enum`` +and enum ``symbol``, creating cross-references for all of them. + +It is also capable of distinguishing ``#define`` used for specifying +Linux-specific macros used to define ``ioctl``. + +The optional ``FILE_RULES`` contains a set of rules like:: + + ignore ioctl VIDIOC_ENUM_FMT + replace ioctl VIDIOC_DQBUF vidioc_qbuf + replace define V4L2_EVENT_MD_FL_HAVE_FRAME_SEQ :c:type:`v4l2_event_motion_det` + +POSITIONAL ARGUMENTS +******************** + + ``FILE_IN`` + Input C file + + ``FILE_OUT`` + Output RST file + + ``FILE_RULES`` + Exceptions file (optional) + +OPTIONS +******* + + ``-h``, ``--help`` + show a help message and exit + ``-d``, ``--debug`` + Increase debug level. Can be used multiple times + ``-t``, ``--toc`` + instead of a literal block, outputs a TOC table at the RST file + + +DESCRIPTION +*********** + +Creates an enriched version of a Kernel header file with cross-links +to each C data structure type, from ``FILE_IN``, formatting it with +reStructuredText notation, either as-is or as a table of contents. + +It accepts an optional ``FILE_RULES`` which describes what elements will be +either ignored or be pointed to a non-default reference, and optionally +defines the C namespace to be used. + +It is meant to allow having more comprehensive documentation, where +uAPI headers will create cross-reference links to the code. + +The output is written at the ``FILE_OUT``. + +The ``FILE_RULES`` may contain contain three types of statements: +**ignore**, **replace** and **namespace**. + +By default, it create rules for all symbols and defines, but it also +allows parsing an exception file. Such file contains a set of rules +using the syntax below: + +1. Ignore rules: + + ignore *type* *symbol* + +Removes the symbol from reference generation. + +2. Replace rules: + + replace *type* *old_symbol* *new_reference* + + Replaces *old_symbol* with a *new_reference*. + The *new_reference* can be: + + - A simple symbol name; + - A full Sphinx reference. + +3. Namespace rules + + namespace *namespace* + + Sets C *namespace* to be used during cross-reference generation. Can + be overridden by replace rules. + +On ignore and replace rules, *type* can be: + + - ioctl: + for defines of the form ``_IO*``, e.g., ioctl definitions + + - define: + for other defines + + - symbol: + for symbols defined within enums; + + - typedef: + for typedefs; + + - enum: + for the name of a non-anonymous enum; + + - struct: + for structs. + + +EXAMPLES +******** + +- Ignore a define ``_VIDEODEV2_H`` at ``FILE_IN``:: + + ignore define _VIDEODEV2_H + +- On an data structure like this enum:: + + enum foo { BAR1, BAR2, PRIVATE }; + + It won't generate cross-references for ``PRIVATE``:: + + ignore symbol PRIVATE + + At the same struct, instead of creating one cross reference per symbol, + make them all point to the ``enum foo`` C type:: + + replace symbol BAR1 :c:type:\`foo\` + replace symbol BAR2 :c:type:\`foo\` + + +- Use C namespace ``MC`` for all symbols at ``FILE_IN``:: + + namespace MC + +BUGS +**** + + +Report bugs to Mauro Carvalho Chehab + + +COPYRIGHT +********* + + +Copyright (c) 2016, 2025 by Mauro Carvalho Chehab . + +License GPLv2: GNU GPL version 2 . + +This is free software: you are free to change and redistribute it. +There is NO WARRANTY, to the extent permitted by law. -- cgit v1.3.1