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/ftrace2bconf.sh | 262 +++++++++++++++++++++++++++++++ 1 file changed, 262 insertions(+) create mode 100755 tools/bootconfig/scripts/ftrace2bconf.sh (limited to 'tools/bootconfig/scripts/ftrace2bconf.sh') diff --git a/tools/bootconfig/scripts/ftrace2bconf.sh b/tools/bootconfig/scripts/ftrace2bconf.sh new file mode 100755 index 000000000..8eed445c2 --- /dev/null +++ b/tools/bootconfig/scripts/ftrace2bconf.sh @@ -0,0 +1,262 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only + +usage() { + echo "Dump boot-time tracing bootconfig from ftrace" + echo "Usage: $0 [--debug] [ > BOOTCONFIG-FILE]" + exit 1 +} + +DEBUG= +while [ x"$1" != x ]; do + case "$1" in + "--debug") + DEBUG=$1;; + -*) + usage + ;; + esac + shift 1 +done + +if [ x"$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." + exit 1 + fi + TRACEFS=`grep -m 1 -w debugfs /proc/mounts | cut -f 2 -d " "`/tracing + if [ ! -d $TRACEFS ]; then + echo "Error: ftrace is not enabled on this kernel." 1>&2 + exit 1 + fi +fi + +######## main ######### + +set -e + +emit_kv() { # key =|+= value + echo "$@" +} + +global_options() { + val=`cat $TRACEFS/max_graph_depth` + [ $val != 0 ] && emit_kv kernel.fgraph_max_depth = $val + if grep -qv "^#" $TRACEFS/set_graph_function $TRACEFS/set_graph_notrace ; then + cat 1>&2 << EOF +# WARN: kernel.fgraph_filters and kernel.fgraph_notrace are not supported, since the wild card expression was expanded and lost from memory. +EOF + fi +} + +kprobe_event_options() { + cat $TRACEFS/kprobe_events | while read p args; do + case $p in + \#*) + continue;; + r*) + cat 1>&2 << EOF +# WARN: A return probe found but it is not supported by bootconfig. Skip it. +EOF + continue;; + esac + p=${p#*:} + event=${p#*/} + group=${p%/*} + if [ $group != "kprobes" ]; then + cat 1>&2 << EOF +# WARN: kprobes group name $group is changed to "kprobes" for bootconfig. +EOF + fi + emit_kv $PREFIX.event.kprobes.$event.probes += $args + done +} + +synth_event_options() { + cat $TRACEFS/synthetic_events | while read event fields; do + emit_kv $PREFIX.event.synthetic.$event.fields = `echo $fields | sed "s/;/,/g"` + done +} + +# Variables resolver +DEFINED_VARS= +UNRESOLVED_EVENTS= + +defined_vars() { # event-dir + grep "^hist" $1/trigger | grep -o ':[a-zA-Z0-9]*=' +} +referred_vars() { + grep "^hist" $1/trigger | grep -o '$[a-zA-Z0-9]*' +} + +event_is_enabled() { # enable-file + test -f $1 && grep -q "1" $1 +} + +per_event_options() { # event-dir + evdir=$1 + # Check the special event which has no filter and no trigger + [ ! -f $evdir/filter ] && return + + if grep -q "^hist:" $evdir/trigger; then + # hist action can refer the undefined variables + __vars=`defined_vars $evdir` + for v in `referred_vars $evdir`; do + if echo $DEFINED_VARS $__vars | grep -vqw ${v#$}; then + # $v is not defined yet, defer it + UNRESOLVED_EVENTS="$UNRESOLVED_EVENTS $evdir" + return; + fi + done + DEFINED_VARS="$DEFINED_VARS "`defined_vars $evdir` + fi + grep -v "^#" $evdir/trigger | while read action active; do + emit_kv $PREFIX.event.$group.$event.actions += \'$action\' + done + + if [ $GROUP_ENABLED -eq 0 ] && event_is_enabled $evdir/enable; then + emit_kv $PREFIX.event.$group.$event.enable + fi + val=`cat $evdir/filter` + if [ "$val" != "none" ]; then + emit_kv $PREFIX.event.$group.$event.filter = "$val" + fi +} + +retry_unresolved() { + unresolved=$UNRESOLVED_EVENTS + UNRESOLVED_EVENTS= + for evdir in $unresolved; do + event=${evdir##*/} + group=${evdir%/*}; group=${group##*/} + per_event_options $evdir + done +} + +event_options() { + # PREFIX and INSTANCE must be set + if [ $PREFIX = "ftrace" ]; then + # define the dynamic events + kprobe_event_options + synth_event_options + fi + ALL_ENABLED=0 + if event_is_enabled $INSTANCE/events/enable; then + emit_kv $PREFIX.event.enable + ALL_ENABLED=1 + fi + for group in `ls $INSTANCE/events/` ; do + [ ! -d $INSTANCE/events/$group ] && continue + GROUP_ENABLED=$ALL_ENABLED + if [ $ALL_ENABLED -eq 0 ] && \ + event_is_enabled $INSTANCE/events/$group/enable ;then + emit_kv $PREFIX.event.$group.enable + GROUP_ENABLED=1 + fi + for event in `ls $INSTANCE/events/$group/` ;do + [ ! -d $INSTANCE/events/$group/$event ] && continue + per_event_options $INSTANCE/events/$group/$event + done + done + retry=0 + while [ $retry -lt 3 ]; do + retry_unresolved + retry=$((retry + 1)) + done + if [ "$UNRESOLVED_EVENTS" ]; then + cat 1>&2 << EOF +! ERROR: hist triggers in $UNRESOLVED_EVENTS use some undefined variables. +EOF + fi +} + +is_default_trace_option() { # option +grep -qw $1 << EOF +print-parent +nosym-offset +nosym-addr +noverbose +noraw +nohex +nobin +noblock +trace_printk +annotate +nouserstacktrace +nosym-userobj +noprintk-msg-only +context-info +nolatency-format +record-cmd +norecord-tgid +overwrite +nodisable_on_free +irq-info +markers +noevent-fork +nopause-on-trace +function-trace +nofunction-fork +nodisplay-graph +nostacktrace +notest_nop_accept +notest_nop_refuse +EOF +} + +instance_options() { # [instance-name] + if [ $# -eq 0 ]; then + PREFIX="ftrace" + INSTANCE=$TRACEFS + else + PREFIX="ftrace.instance.$1" + INSTANCE=$TRACEFS/instances/$1 + fi + val= + for i in `cat $INSTANCE/trace_options`; do + is_default_trace_option $i && continue + val="$val, $i" + done + [ "$val" ] && emit_kv $PREFIX.options = "${val#,}" + val="local" + for i in `cat $INSTANCE/trace_clock` ; do + [ "${i#*]}" ] && continue + i=${i%]}; val=${i#[} + done + [ $val != "local" ] && emit_kv $PREFIX.trace_clock = $val + val=`cat $INSTANCE/buffer_size_kb` + if echo $val | grep -vq "expanded" ; then + emit_kv $PREFIX.buffer_size = $val"KB" + fi + if grep -q "is allocated" $INSTANCE/snapshot ; then + emit_kv $PREFIX.alloc_snapshot + fi + val=`cat $INSTANCE/tracing_cpumask` + if [ `echo $val | sed -e s/f//g`x != x ]; then + emit_kv $PREFIX.cpumask = $val + fi + val=`cat $INSTANCE/tracing_on` + if [ "$val" = "0" ]; then + emit_kv $PREFIX.tracing_on = 0 + fi + + val=`cat $INSTANCE/current_tracer` + [ $val != nop ] && emit_kv $PREFIX.tracer = $val + if grep -qv "^#" $INSTANCE/set_ftrace_filter $INSTANCE/set_ftrace_notrace; then + cat 1>&2 << EOF +# WARN: kernel.ftrace.filters and kernel.ftrace.notrace are not supported, since the wild card expression was expanded and lost from memory. +EOF + fi + event_options +} + +global_options +instance_options +for i in `ls $TRACEFS/instances` ; do + instance_options $i +done -- cgit v1.3.1