perf test kvm: Add some basic perf kvm test coverage

Setup qemu with KVM then run kvm stat and some host
recording/reporting/build-id tests.

Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Author: captain5050

tools/perf/tests/shell/kvm.sh

@@ -0,0 +1,154 @@
+#!/bin/bash
+# perf kvm tests
+# SPDX-License-Identifier: GPL-2.0
+
+set -e
+
+err=0
+perfdata=$(mktemp /tmp/__perf_kvm_test.perf.data.XXXXX)
+qemu_pid_file=$(mktemp /tmp/__perf_kvm_test.qemu.pid.XXXXX)
+
+cleanup() {
+	rm -f "${perfdata}"
+	if [ -f "${qemu_pid_file}" ]; then
+		if [ -s "${qemu_pid_file}" ]; then
+			qemu_pid=$(cat "${qemu_pid_file}")
+			if [ -n "${qemu_pid}" ]; then
+				kill "${qemu_pid}" 2>/dev/null || true
+			fi
+		fi
+		rm -f "${qemu_pid_file}"
+	fi
+	trap - EXIT TERM INT
+}
+
+trap_cleanup() {
+	echo "Unexpected signal in ${FUNCNAME[1]}"
+	cleanup
+	exit 1
+}
+trap trap_cleanup EXIT TERM INT
+
+skip() {
+	echo "Skip: $1"
+	cleanup
+	exit 2
+}
+
+test_kvm_stat() {
+	echo "Testing perf kvm stat"
+
+	echo "Recording kvm events for pid ${qemu_pid}..."
+	if ! perf kvm stat record -p "${qemu_pid}" -o "${perfdata}" sleep 1; then
+		echo "Failed to record kvm events"
+		err=1
+		return
+	fi
+
+	echo "Reporting kvm events..."
+	if ! perf kvm -i "${perfdata}" stat report 2>&1 | grep -q "VM-EXIT"; then
+		echo "Failed to find VM-EXIT in report"
+		perf kvm -i "${perfdata}" stat report 2>&1
+		err=1
+		return
+	fi
+
+	echo "perf kvm stat test [Success]"
+}
+
+test_kvm_record_report() {
+	echo "Testing perf kvm record/report"
+
+	echo "Recording kvm profile for pid ${qemu_pid}..."
+	# Use --host to avoid needing guest symbols/mounts for this simple test
+	# We just want to verify the command runs and produces data
+	# We run in background and kill it because 'perf kvm record' appends options
+	# after the command, which breaks 'sleep' (e.g. it gets '-e cycles').
+	perf kvm --host record -p "${qemu_pid}" -o "${perfdata}" &
+	rec_pid=$!
+	sleep 1
+	kill -INT "${rec_pid}"
+	wait "${rec_pid}" || true
+
+	echo "Reporting kvm profile..."
+	# Check for some standard output from report
+	if ! perf kvm -i "${perfdata}" report --stdio 2>&1 | grep -q "Event count"; then
+		echo "Failed to report kvm profile"
+		perf kvm -i "${perfdata}" report --stdio 2>&1
+		err=1
+		return
+	fi
+
+	echo "perf kvm record/report test [Success]"
+}
+
+test_kvm_buildid_list() {
+	echo "Testing perf kvm buildid-list"
+
+	# We reuse the perf.data from the previous record test
+	if ! perf kvm --host -i "${perfdata}" buildid-list 2>&1 | grep -q "."; then
+		echo "Failed to list buildids"
+		perf kvm --host -i "${perfdata}" buildid-list 2>&1
+		err=1
+		return
+	fi
+
+	echo "perf kvm buildid-list test [Success]"
+}
+
+setup_qemu() {
+	# Find qemu
+	if [ "$(uname -m)" = "x86_64" ]; then
+		qemu="qemu-system-x86_64"
+	elif [ "$(uname -m)" = "aarch64" ]; then
+		qemu="qemu-system-aarch64"
+	elif [ "$(uname -m)" = "s390x" ]; then
+		qemu="qemu-system-s390x"
+	elif [ "$(uname -m)" = "ppc64le" ]; then
+		qemu="qemu-system-ppc64"
+	else
+		qemu="qemu-system-$(uname -m)"
+	fi
+
+	if ! which -s "$qemu"; then
+		skip "$qemu not found"
+	fi
+
+	if [ ! -r /dev/kvm ] || [ ! -w /dev/kvm ]; then
+		skip "/dev/kvm not accessible"
+	fi
+
+	if ! perf kvm stat record -a sleep 0.01 >/dev/null 2>&1; then
+		skip "No permission to record kvm events"
+	fi
+
+	echo "Starting $qemu..."
+	# Start qemu in background, detached, with pidfile
+	# We use -display none -daemonize and a monitor to keep it alive/controllable if needed
+	# We don't need a real kernel, just KVM active.
+	if ! $qemu -enable-kvm -display none -daemonize -pidfile "${qemu_pid_file}" -monitor none; then
+		echo "Failed to start qemu"
+		err=1
+		return
+	fi
+
+	# Wait a bit for qemu to start
+	sleep 1
+	qemu_pid=$(cat "${qemu_pid_file}")
+
+	if ! kill -0 "${qemu_pid}" 2>/dev/null; then
+		echo "Qemu process failed to stay alive"
+		err=1
+		return
+	fi
+}
+
+setup_qemu
+if [ $err -eq 0 ]; then
+	test_kvm_stat
+	test_kvm_record_report
+	test_kvm_buildid_list
+fi
+
+cleanup
+exit $err