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 --- tools/bootconfig/scripts/bconf2ftrace.sh | 301 +++++++++++++++++++++++++++++++ 1 file changed, 301 insertions(+) create mode 100755 tools/bootconfig/scripts/bconf2ftrace.sh (limited to 'tools/bootconfig/scripts/bconf2ftrace.sh') diff --git a/tools/bootconfig/scripts/bconf2ftrace.sh b/tools/bootconfig/scripts/bconf2ftrace.sh new file mode 100755 index 000000000..850c20734 --- /dev/null +++ b/tools/bootconfig/scripts/bconf2ftrace.sh @@ -0,0 +1,301 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only + +usage() { + echo "Ftrace boottime trace test tool" + echo "Usage: $0 [--apply|--init] [--debug] BOOTCONFIG-FILE" + echo " --apply: Test actual apply to tracefs (need sudo)" + echo " --init: Initialize ftrace before applying (imply --apply)" + exit 1 +} + +[ $# -eq 0 ] && usage + +BCONF= +DEBUG= +APPLY= +INIT= +while [ x"$1" != x ]; do + case "$1" in + "--debug") + DEBUG=$1;; + "--apply") + APPLY=$1;; + "--init") + APPLY=$1 + INIT=$1;; + *) + [ ! -f $1 ] && usage + BCONF=$1;; + esac + shift 1 +done + +if [ x"$APPLY" != x ]; then + if [ `id -u` -ne 0 ]; then + echo "This must be run by root user. Try sudo." 1>&2 + exec sudo $0 $DEBUG $APPLY $BCONF + fi +fi + +run_cmd() { # command + echo "$*" + if [ x"$APPLY" != x ]; then # apply command + eval $* + fi +} + +if [ x"$DEBUG" != x ]; then + set -x +fi + +TRACEFS=`grep -m 1 -w tracefs /proc/mounts | cut -f 2 -d " "` +if [ -z "$TRACEFS" ]; then + if ! grep -wq debugfs /proc/mounts; then + echo "Error: No tracefs/debugfs was mounted." 1>&2 + exit 1 + fi + TRACEFS=`grep -m 1 -w debugfs /proc/mounts | cut -f 2 -d " "`/tracing + if [ ! -d $TRACEFS ]; then + echo "Error: ftrace is not enabled on this kernel." 1>&2 + exit 1 + fi +fi + +if [ x"$INIT" != x ]; then + . `dirname $0`/ftrace.sh + (cd $TRACEFS; initialize_ftrace) +fi + +. `dirname $0`/xbc.sh + +######## main ######### +set -e + +xbc_init $BCONF + +set_value_of() { # key file + if xbc_has_key $1; then + val=`xbc_get_val $1 1` + run_cmd "echo '$val' >> $2" + fi +} + +set_array_of() { # key file + if xbc_has_key $1; then + xbc_get_val $1 | while read line; do + run_cmd "echo '$line' >> $2" + done + fi +} + +compose_synth() { # event_name branch + echo -n "$1 " + xbc_get_val $2 | while read field; do echo -n "$field; "; done +} + +print_hist_array() { # prefix key + __sep="=" + if xbc_has_key ${1}.${2}; then + echo -n ":$2" + xbc_get_val ${1}.${2} | while read field; do + echo -n "$__sep$field"; __sep="," + done + fi +} + +print_hist_action_array() { # prefix key + __sep="(" + echo -n ".$2" + xbc_get_val ${1}.${2} | while read field; do + echo -n "$__sep$field"; __sep="," + done + echo -n ")" +} + +print_hist_one_action() { # prefix handler param + echo -n ":${2}("`xbc_get_val ${1}.${3}`")" + if xbc_has_key "${1}.trace"; then + print_hist_action_array ${1} "trace" + elif xbc_has_key "${1}.save"; then + print_hist_action_array ${1} "save" + elif xbc_has_key "${1}.snapshot"; then + echo -n ".snapshot()" + fi +} + +print_hist_actions() { # prefix handler param + for __hdr in `xbc_subkeys ${1}.${2} 1 ".[0-9]"`; do + print_hist_one_action ${1}.${2}.$__hdr ${2} ${3} + done + if xbc_has_key ${1}.${2}.${3} ; then + print_hist_one_action ${1}.${2} ${2} ${3} + fi +} + +print_hist_var() { # prefix varname + echo -n ":${2}="`xbc_get_val ${1}.var.${2} | tr -d [:space:]` +} + +print_one_histogram() { # prefix + echo -n "hist" + print_hist_array $1 "keys" + print_hist_array $1 "values" + print_hist_array $1 "sort" + if xbc_has_key "${1}.size"; then + echo -n ":size="`xbc_get_val ${1}.size` + fi + if xbc_has_key "${1}.name"; then + echo -n ":name="`xbc_get_val ${1}.name` + fi + for __var in `xbc_subkeys "${1}.var" 1`; do + print_hist_var ${1} ${__var} + done + if xbc_has_key "${1}.pause"; then + echo -n ":pause" + elif xbc_has_key "${1}.continue"; then + echo -n ":continue" + elif xbc_has_key "${1}.clear"; then + echo -n ":clear" + fi + print_hist_actions ${1} "onmax" "var" + print_hist_actions ${1} "onchange" "var" + print_hist_actions ${1} "onmatch" "event" + + if xbc_has_key "${1}.filter"; then + echo -n " if "`xbc_get_val ${1}.filter` + fi +} + +setup_one_histogram() { # prefix trigger-file + run_cmd "echo '`print_one_histogram ${1}`' >> ${2}" +} + +setup_histograms() { # prefix trigger-file + for __hist in `xbc_subkeys ${1} 1 ".[0-9]"`; do + setup_one_histogram ${1}.$__hist ${2} + done + if xbc_has_key ${1}.keys; then + setup_one_histogram ${1} ${2} + fi +} + +setup_event() { # prefix group event [instance] + branch=$1.$2.$3 + if [ "$4" ]; then + eventdir="$TRACEFS/instances/$4/events/$2/$3" + else + eventdir="$TRACEFS/events/$2/$3" + fi + # group enable + if [ "$3" = "enable" ]; then + run_cmd "echo 1 > ${eventdir}" + return + fi + + case $2 in + kprobes) + xbc_get_val ${branch}.probes | while read line; do + run_cmd "echo 'p:kprobes/$3 $line' >> $TRACEFS/kprobe_events" + done + ;; + synthetic) + run_cmd "echo '`compose_synth $3 ${branch}.fields`' >> $TRACEFS/synthetic_events" + ;; + esac + + set_value_of ${branch}.filter ${eventdir}/filter + set_array_of ${branch}.actions ${eventdir}/trigger + + setup_histograms ${branch}.hist ${eventdir}/trigger + + if xbc_has_key ${branch}.enable; then + run_cmd "echo 1 > ${eventdir}/enable" + fi +} + +setup_events() { # prefix("ftrace" or "ftrace.instance.INSTANCE") [instance] + prefix="${1}.event" + if xbc_has_branch ${1}.event; then + for grpev in `xbc_subkeys ${1}.event 2`; do + setup_event $prefix ${grpev%.*} ${grpev#*.} $2 + done + fi + if xbc_has_branch ${1}.event.enable; then + if [ "$2" ]; then + run_cmd "echo 1 > $TRACEFS/instances/$2/events/enable" + else + run_cmd "echo 1 > $TRACEFS/events/enable" + fi + fi +} + +size2kb() { # size[KB|MB] + case $1 in + *KB) + echo ${1%KB};; + *MB) + expr ${1%MB} \* 1024;; + *) + expr $1 / 1024 ;; + esac +} + +setup_instance() { # [instance] + if [ "$1" ]; then + instance="ftrace.instance.${1}" + instancedir=$TRACEFS/instances/$1 + else + instance="ftrace" + instancedir=$TRACEFS + fi + + set_array_of ${instance}.options ${instancedir}/trace_options + set_value_of ${instance}.trace_clock ${instancedir}/trace_clock + set_value_of ${instance}.cpumask ${instancedir}/tracing_cpumask + set_value_of ${instance}.tracing_on ${instancedir}/tracing_on + set_value_of ${instance}.tracer ${instancedir}/current_tracer + set_array_of ${instance}.ftrace.filters \ + ${instancedir}/set_ftrace_filter + set_array_of ${instance}.ftrace.notrace \ + ${instancedir}/set_ftrace_notrace + + if xbc_has_key ${instance}.alloc_snapshot; then + run_cmd "echo 1 > ${instancedir}/snapshot" + fi + + if xbc_has_key ${instance}.buffer_size; then + size=`xbc_get_val ${instance}.buffer_size 1` + size=`eval size2kb $size` + run_cmd "echo $size >> ${instancedir}/buffer_size_kb" + fi + + setup_events ${instance} $1 + set_array_of ${instance}.events ${instancedir}/set_event +} + +# ftrace global configs (kernel.*) +if xbc_has_key "kernel.dump_on_oops"; then + dump_mode=`xbc_get_val "kernel.dump_on_oops" 1` + [ "$dump_mode" ] && dump_mode=`eval echo $dump_mode` || dump_mode=1 + run_cmd "echo \"$dump_mode\" > /proc/sys/kernel/ftrace_dump_on_oops" +fi + +set_value_of kernel.fgraph_max_depth $TRACEFS/max_graph_depth +set_array_of kernel.fgraph_filters $TRACEFS/set_graph_function +set_array_of kernel.fgraph_notraces $TRACEFS/set_graph_notrace + +# Per-instance/per-event configs +if ! xbc_has_branch "ftrace" ; then + exit 0 +fi + +setup_instance # root instance + +if xbc_has_branch "ftrace.instance"; then + for i in `xbc_subkeys "ftrace.instance" 1`; do + run_cmd "mkdir -p $TRACEFS/instances/$i" + setup_instance $i + done +fi + -- cgit v1.3.1