tools/testing/selftests/hyp-trace/hyp-trace-test

#!/bin/sh -e
# SPDX-License-Identifier: GPL-2.0-only

# hyp-trace-test - Tracefs for pKVM hypervisor test
#
# Copyright (C) 2024 - Google LLC
# Author: Vincent Donnefort <vdonnefort@google.com>
#

log_and_die()
{
    echo "$1"

    exit 1
}

host_clock()
{
    # BOOTTIME clock
    awk '/now/ { printf "%.6f\n", $3 / 1000000000 }' /proc/timer_list
}

page_size()
{
    echo "$(awk '/KernelPageSize/ {print $2; exit}' /proc/self/smaps) * 1024" | bc
}

goto_hyp_trace()
{
    if [ -d "/sys/kernel/debug/tracing/hypervisor" ]; then
        cd /sys/kernel/debug/tracing/hypervisor
        return
    fi

    if [ -d "/sys/kernel/tracing/hypervisor" ]; then
        cd /sys/kernel/tracing/hypervisor
        return
    fi

    echo "ERROR: hyp tracing folder not found!"

    exit 1
}

reset_hyp_trace()
{
    echo 0 > tracing_on
    echo 0 > trace
    for event in events/hypervisor/*; do
        echo 0 > $event/enable
    done
}

setup_hyp_trace()
{
    reset_hyp_trace

    echo 16 > buffer_size_kb
    echo 1 > events/hypervisor/selftest/enable
    echo 1 > tracing_on
}

stop_hyp_trace()
{
    echo 0 > tracing_on
}

hyp_trace_loaded()
{
    grep -q "(loaded)" buffer_size_kb
}

write_events()
{
    local num="$1"
    local func="$2"

    for i in $(seq 1 $num); do
        echo 1 > selftest_event
        [ -z "$func" -o $i -eq $num ] || eval $func
    done
}

consuming_read()
{
    local output=$1

    cat trace_pipe > $output &

    echo $!
}

run_test_consuming()
{
    local nr_events=$1
    local func=$2
    local tmp="$(mktemp)"
    local start_ts=0
    local end_ts=0
    local pid=0

    echo "Output trace file: $tmp"

    setup_hyp_trace
    pid=$(consuming_read $tmp)

    start_ts=$(host_clock)
    write_events $nr_events $func
    stop_hyp_trace
    end_ts=$(host_clock)

    kill $pid
    validate_test $tmp $nr_events $start_ts $end_ts

    rm $tmp
}

validate_test()
{
    local output=$1
    local expected_events=$2
    local start_ts=$3
    local end_ts=$4
    local prev_ts=$3
    local ts=0
    local num_events=0

    IFS=$'\n'
    for line in $(cat $output); do
        echo "$line" | grep -q -E "^# " && continue
        ts=$(echo "$line" | awk '{print $2}' | cut -d ':' -f1)
        if [ $(echo "$ts<$prev_ts" | bc) -eq 1 ]; then
            log_and_die "Error event @$ts < $prev_ts"
        fi
        prev_ts=$ts
        num_events=$((num_events + 1))
    done

    if [ $(echo "$ts>$end_ts" | bc) -eq 1 ]; then
        log_and_die "Error event @$ts > $end_ts"
    fi

    if [ $num_events -ne $expected_events ]; then
        log_and_die "Expected $expected_events events, got $num_events"
    fi
}

test_ts()
{
    echo "Test Timestamps..."

    run_test_consuming 1000

    echo "done."
}

test_extended_ts()
{
    echo "Test Extended Timestamps..."

    run_test_consuming 1000 "sleep 0.1"

    echo "done."
}

assert_loaded()
{
    hyp_trace_loaded || log_and_die "Expected loaded buffer"
}

assert_unloaded()
{
    ! hyp_trace_loaded || log_and_die "Expected unloaded buffer"
}

test_unloading()
{
    local tmp="$(mktemp)"

    echo "Test unloading..."

    setup_hyp_trace
    assert_loaded

    echo 0 > tracing_on
    assert_unloaded

    pid=$(consuming_read $tmp)
    sleep 1
    assert_loaded
    kill $pid
    assert_unloaded

    echo 1 > tracing_on
    write_events 1
    echo 0 > trace
    assert_loaded
    echo 0 > tracing_on
    assert_unloaded

    echo "done."
}

test_reset()
{
    local tmp="$(mktemp)"

    echo "Test Reset..."

    setup_hyp_trace
    write_events 5
    echo 0 > trace
    write_events 5

    pid=$(consuming_read $tmp)
    sleep 1
    stop_hyp_trace
    kill $pid

    validate_test $tmp 5 0 $(host_clock)

    rm $tmp

    echo "done."
}

test_big_bpacking()
{
    local hyp_buffer_page_size=48
    local page_size=$(page_size)
    local min_buf_size=$(echo "$page_size * $page_size / ($hyp_buffer_page_size * $(nproc))" | bc)

    min_buf_size=$(echo "$min_buf_size * 2 / 1024" | bc)

    echo "Test loading $min_buf_size kB buffer..."

    reset_hyp_trace
    echo $min_buf_size > buffer_size_kb
    echo 1 > tracing_on

    stop_hyp_trace

    echo "done."
}

goto_hyp_trace

test_reset
test_unloading
test_big_bpacking
test_ts
test_extended_ts

exit 0