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 --- scripts/check-sysctl-docs | 174 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 174 insertions(+) create mode 100755 scripts/check-sysctl-docs (limited to 'scripts/check-sysctl-docs') diff --git a/scripts/check-sysctl-docs b/scripts/check-sysctl-docs new file mode 100755 index 000000000..910fd8a9a --- /dev/null +++ b/scripts/check-sysctl-docs @@ -0,0 +1,174 @@ +#!/usr/bin/env -S gawk -f +# SPDX-License-Identifier: GPL-2.0 + +# Script to check sysctl documentation against source files +# +# Copyright (c) 2020 Stephen Kitt + +# Example invocation: +# scripts/check-sysctl-docs -vtable="kernel" \ +# Documentation/admin-guide/sysctl/kernel.rst \ +# $(git grep -l register_sysctl) +# +# Specify -vdebug=1 to see debugging information + +BEGIN { + if (!table) { + print "Please specify the table to look for using the table variable" > "/dev/stderr" + exit 1 + } + + # Documentation title skiplist + skiplist[0] = "^Documentation for" + skiplist[1] = "Network core options$" + skiplist[2] = "POSIX message queues filesystem$" + skiplist[3] = "Configuration options" + skiplist[4] = ". /proc/sys/fs" + skiplist[5] = "^Introduction$" + skiplist[6] = "^seccomp$" + skiplist[7] = "^pty$" + skiplist[8] = "^firmware_config$" + skiplist[9] = "^random$" +} + +# The following globals are used: +# documented: maps documented entries (each key is an entry) +# entries: maps ctl_table names and procnames to counts (so +# enumerating the subkeys for a given ctl_table lists its +# procnames) +# curtable: the name of the current ctl_table struct +# curentry: the name of the current proc entry (procname when parsing +# a ctl_table, constructed path when parsing a ctl_path) + + +# Remove punctuation from the given value +function trimpunct(value) { + while (value ~ /^["&]/) { + value = substr(value, 2) + } + while (value ~ /[]["&,}]$/) { + value = substr(value, 1, length(value) - 1) + } + return value +} + +# Print the information for the given entry +function printentry(entry) { + seen[entry]++ + printf "* %s from %s", entry, file[entry] + if (documented[entry]) { + printf " (documented)" + } + print "" +} + + +# Stage 1: build the list of documented entries +FNR == NR && /^=+$/ { + for (i in skiplist) { + if (prevline ~ skiplist[i]) { + next + } + } + + # The previous line is a section title, parse it + $0 = prevline + if (debug) print "Parsing " $0 + inbrackets = 0 + for (i = 1; i <= NF; i++) { + if (length($i) == 0) { + continue + } + if (!inbrackets && substr($i, 1, 1) == "(") { + inbrackets = 1 + } + if (!inbrackets) { + token = trimpunct($i) + if (length(token) > 0 && token != "and") { + if (debug) print trimpunct($i) + documented[trimpunct($i)]++ + } + } + if (inbrackets && substr($i, length($i), 1) == ")") { + inbrackets = 0 + } + } +} + +FNR == NR { + prevline = $0 + next +} + + +# Stage 2: process each file and find all sysctl tables +BEGINFILE { + delete entries + curtable = "" + curentry = "" + delete vars + if (debug) print "Processing file " FILENAME +} + +/^static( const)? struct ctl_table/ { + match($0, /static( const)? struct ctl_table ([^][]+)/, tables) + curtable = tables[2] + if (debug) print "Processing table " curtable +} + +/^};$/ { + curtable = "" + curentry = "" + delete vars +} + +curtable && /\.procname[\t ]*=[\t ]*".+"/ { + match($0, /.procname[\t ]*=[\t ]*"([^"]+)"/, names) + curentry = names[1] + if (debug) print "Adding entry " curentry " to table " curtable + entries[curtable][curentry]++ + file[curentry] = FILENAME +} + +curtable && /UCOUNT_ENTRY.*/ { + match($0, /UCOUNT_ENTRY\("([^"]+)"\)/, names) + curentry = names[1] + if (debug) print "Adding entry " curentry " to table " curtable + entries[curtable][curentry]++ + file[curentry] = FILENAME +} + +/register_sysctl.*/ { + match($0, /register_sysctl(|_init|_sz)\("([^"]+)" *, *([^,)]+)/, tables) + if (debug) print "Registering table " tables[3] " at " tables[2] + if (tables[2] == table) { + for (entry in entries[tables[3]]) { + printentry(entry) + } + } +} + +/kmemdup.*/ { + match($0, /([^ \t]+) *= *kmemdup\(([^,]+) *,/, names) + if (debug) print "Found variable " names[1] " for table " names[2] + if (names[2] in entries) { + vars[names[1]] = names[2] + } +} + +/__register_sysctl_table.*/ { + match($0, /__register_sysctl_table\([^,]+, *"([^"]+)" *, *([^,]+)/, tables) + if (debug) print "Registering variable table " tables[2] " at " tables[1] + if (tables[1] == table && tables[2] in vars) { + for (entry in entries[vars[tables[2]]]) { + printentry(entry) + } + } +} + +END { + for (entry in documented) { + if (!seen[entry]) + print "No implementation for " entry + } +} -- cgit v1.3.1