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/sphinx/kernel_feat.py | 137 ++++++++++++++++++++++++++++++++++++ 1 file changed, 137 insertions(+) create mode 100644 Documentation/sphinx/kernel_feat.py (limited to 'Documentation/sphinx/kernel_feat.py') diff --git a/Documentation/sphinx/kernel_feat.py b/Documentation/sphinx/kernel_feat.py new file mode 100644 index 000000000..bdc0fef5c --- /dev/null +++ b/Documentation/sphinx/kernel_feat.py @@ -0,0 +1,137 @@ +# coding=utf-8 +# SPDX-License-Identifier: GPL-2.0 +# +""" + kernel-feat + ~~~~~~~~~~~ + + Implementation of the ``kernel-feat`` reST-directive. + + :copyright: Copyright (C) 2016 Markus Heiser + :copyright: Copyright (C) 2016-2019 Mauro Carvalho Chehab + :maintained-by: Mauro Carvalho Chehab + :license: GPL Version 2, June 1991 see Linux/COPYING for details. + + The ``kernel-feat`` (:py:class:`KernelFeat`) directive calls the + tools/docs/get_feat.pl script to parse the Kernel ABI files. + + Overview of directive's argument and options. + + .. code-block:: rst + + .. kernel-feat:: + :debug: + + The argument ```` is required. It contains the + location of the ABI files to be parsed. + + ``debug`` + Inserts a code-block with the *raw* reST. Sometimes it is helpful to see + what reST is generated. + +""" + +import codecs +import os +import re +import sys + +from docutils import nodes, statemachine +from docutils.statemachine import ViewList +from docutils.parsers.rst import directives, Directive +from sphinx.util.docutils import switch_source_input + +srctree = os.path.abspath(os.environ["srctree"]) +sys.path.insert(0, os.path.join(srctree, "tools/lib/python")) + +from feat.parse_features import ParseFeature # pylint: disable=C0413 + +def ErrorString(exc): # Shamelessly stolen from docutils + return f'{exc.__class__.__name}: {exc}' + +__version__ = '1.0' + +def setup(app): + + app.add_directive("kernel-feat", KernelFeat) + return dict( + version = __version__ + , parallel_read_safe = True + , parallel_write_safe = True + ) + +class KernelFeat(Directive): + + """KernelFeat (``kernel-feat``) directive""" + + required_arguments = 1 + optional_arguments = 2 + has_content = False + final_argument_whitespace = True + + option_spec = { + "debug" : directives.flag + } + + def warn(self, message, **replace): + replace["fname"] = self.state.document.current_source + replace["line_no"] = replace.get("line_no", self.lineno) + message = ("%(fname)s:%(line_no)s: [kernel-feat WARN] : " + message) % replace + self.state.document.settings.env.app.warn(message, prefix="") + + def run(self): + doc = self.state.document + if not doc.settings.file_insertion_enabled: + raise self.warning("docutils: file insertion disabled") + + env = doc.settings.env + + srctree = os.path.abspath(os.environ["srctree"]) + + feature_dir = os.path.join(srctree, 'Documentation', self.arguments[0]) + + feat = ParseFeature(feature_dir, False, True) + feat.parse() + + if len(self.arguments) > 1: + arch = self.arguments[1] + lines = feat.output_arch_table(arch) + else: + lines = feat.output_matrix() + + line_regex = re.compile(r"^\.\. FILE (\S+)$") + + out_lines = "" + + for line in lines.split("\n"): + match = line_regex.search(line) + if match: + fname = match.group(1) + + # Add the file to Sphinx build dependencies + env.note_dependency(os.path.abspath(fname)) + else: + out_lines += line + "\n" + + nodeList = self.nestedParse(out_lines, self.arguments[0]) + return nodeList + + def nestedParse(self, lines, fname): + content = ViewList() + node = nodes.section() + + if "debug" in self.options: + code_block = "\n\n.. code-block:: rst\n :linenos:\n" + for l in lines.split("\n"): + code_block += "\n " + l + lines = code_block + "\n\n" + + for c, l in enumerate(lines.split("\n")): + content.append(l, fname, c) + + buf = self.state.memo.title_styles, self.state.memo.section_level, self.state.memo.reporter + + with switch_source_input(self.state, content): + self.state.nested_parse(content, 0, node, match_titles=1) + + return node.children -- cgit v1.3.1