/*
 * QTest testcase for postcopy
 *
 * Copyright (c) 2016 Red Hat, Inc. and/or its affiliates
 *   based on the vhost-user-test.c that is:
 *      Copyright (c) 2014 Virtual Open Systems Sarl.
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#include "qemu/osdep.h"

#include "libqtest.h"
#include "qemu/option.h"
#include "qemu/range.h"
#include "sysemu/char.h"
#include "sysemu/sysemu.h"

#include <qemu/sockets.h>

const unsigned start_address = 1024 * 1024;
const unsigned end_address = 100 * 1024 * 1024;
bool got_stop;

#if defined(__linux__)
#include <sys/syscall.h>
#include <sys/vfs.h>
#endif

#if defined(__linux__) && defined(__NR_userfaultfd) && defined(CONFIG_EVENTFD)
#include <sys/eventfd.h>
#include <sys/ioctl.h>
#include <linux/userfaultfd.h>

static bool ufd_version_check(void)
{
    struct uffdio_api api_struct;
    uint64_t ioctl_mask;

    int ufd = ufd = syscall(__NR_userfaultfd, O_CLOEXEC);

    if (ufd == -1) {
        g_test_message("Skipping test: userfaultfd not available");
        return false;
    }

    api_struct.api = UFFD_API;
    api_struct.features = 0;
    if (ioctl(ufd, UFFDIO_API, &api_struct)) {
        g_test_message("Skipping test: UFFDIO_API failed");
        return false;
    }

    ioctl_mask = (__u64)1 << _UFFDIO_REGISTER |
                 (__u64)1 << _UFFDIO_UNREGISTER;
    if ((api_struct.ioctls & ioctl_mask) != ioctl_mask) {
        g_test_message("Skipping test: Missing userfault feature");
        return false;
    }

    return true;
}

#else
static bool ufd_version_check(void)
{
    g_test_message("Skipping test: Userfault not available (builtdtime)");
    return false;
}

#endif

static const char *tmpfs;

/* A simple PC boot sector that modifies memory (1-100MB) quickly
 * outputing a 'B' every so often if it's still running.
 */
unsigned char bootsect[] = {
  0xfa, 0x0f, 0x01, 0x16, 0x74, 0x7c, 0x66, 0xb8, 0x01, 0x00, 0x00, 0x00,
  0x0f, 0x22, 0xc0, 0x66, 0xea, 0x20, 0x7c, 0x00, 0x00, 0x08, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe4, 0x92, 0x0c, 0x02,
  0xe6, 0x92, 0xb8, 0x10, 0x00, 0x00, 0x00, 0x8e, 0xd8, 0x66, 0xb8, 0x41,
  0x00, 0x66, 0xba, 0xf8, 0x03, 0xee, 0xb3, 0x00, 0xb8, 0x00, 0x00, 0x10,
  0x00, 0xfe, 0x00, 0x05, 0x00, 0x10, 0x00, 0x00, 0x3d, 0x00, 0x00, 0x40,
  0x06, 0x7c, 0xf2, 0xfe, 0xc3, 0x75, 0xe9, 0x66, 0xb8, 0x42, 0x00, 0x66,
  0xba, 0xf8, 0x03, 0xee, 0xeb, 0xde, 0x66, 0x90, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x9a, 0xcf, 0x00,
  0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xcf, 0x00, 0x27, 0x00, 0x5c, 0x7c,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xaa
};

/*
 * Wait for some output in the serial output file,
 * we get an 'A' followed by an endless string of 'B's
 * but on the destination we won't have the A.
 */
static void wait_for_serial(const char *side)
{
    char *serialpath = g_strdup_printf("%s/%s", tmpfs, side);
    FILE *serialfile = fopen(serialpath, "r");

    do {
        int readvalue = fgetc(serialfile);

        switch (readvalue) {
        case 'A':
            /* Fine */
            break;

        case 'B':
            /* It's alive! */
            fclose(serialfile);
            g_free(serialpath);
            return;

        case EOF:
            fseek(serialfile, 0, SEEK_SET);
            usleep(1000);
            break;

        default:
            fprintf(stderr, "Unexpected %d on %s serial\n", readvalue, side);
            g_assert_not_reached();
        }
    } while (true);
}

/*
 * Events can get in the way of responses we are actually waiting for.
 */
static QDict *return_or_event(QDict *response)
{
    const char *event_string;
    if (!qdict_haskey(response, "event")) {
        return response;
    }

    /* OK, it was an event */
    event_string = qdict_get_str(response, "event");
    if (!strcmp(event_string, "STOP")) {
        got_stop = true;
    }
    QDECREF(response);
    return return_or_event(qtest_qmp_receive(global_qtest));
}


/*
 * It's tricky to use qemu's migration event capability with qtest,
 * events suddenly appearing confuse the qmp()/hmp() responses.
 * so wait for a couple of passes to have happened before
 * going postcopy.
 */

static uint64_t get_migration_pass(void)
{
    QDict *rsp, *rsp_return, *rsp_ram;
    uint64_t result;

    rsp = return_or_event(qmp("{ 'execute': 'query-migrate' }"));
    rsp_return = qdict_get_qdict(rsp, "return");
    if (!qdict_haskey(rsp_return, "ram")) {
        /* Still in setup */
        result = 0;
    } else {
        rsp_ram = qdict_get_qdict(rsp_return, "ram");
        result = qdict_get_try_int(rsp_ram, "dirty-sync-count", 0);
        QDECREF(rsp);
    }
    return result;
}

static void wait_for_migration_complete(void)
{
    QDict *rsp, *rsp_return;
    bool completed;

    do {
        const char *status;

        rsp = return_or_event(qmp("{ 'execute': 'query-migrate' }"));
        rsp_return = qdict_get_qdict(rsp, "return");
        status = qdict_get_str(rsp_return, "status");
        completed = strcmp(status, "completed") == 0;
        g_assert_cmpstr(status, !=,  "failed");
        QDECREF(rsp);
        usleep(1000 * 100);
    } while (!completed);
}

static void wait_for_migration_pass(void)
{
    uint64_t initial_pass = get_migration_pass();
    uint64_t pass;

    /* Wait for the 1st sync */
    do {
        initial_pass = get_migration_pass();
        if (got_stop || initial_pass) {
            break;
        }
        usleep(1000 * 100);
    } while (true);

    do {
        usleep(1000 * 100);
        pass = get_migration_pass();
    } while (pass == initial_pass && !got_stop);
}

static void check_guests_ram(void)
{
    /* Our ASM test will have been incrementing one byte from each page from
     * 1MB to <100MB in order.
     * This gives us a constraint that any page's byte should be equal or less
     * than the previous pages byte (mod 256); and they should all be equal
     * except for one transition at the point where we meet the incrementer.
     * (We're running this with the guest stopped).
     */
    unsigned address;
    uint8_t first_byte;
    uint8_t last_byte;
    bool hit_edge = false;
    bool bad = false;

    qtest_memread(global_qtest, start_address, &first_byte, 1);
    last_byte = first_byte;

    for (address = start_address + 4096; address < end_address; address += 4096)
    {
        uint8_t b;
        qtest_memread(global_qtest, address, &b, 1);
        if (b != last_byte) {
            if (((b + 1) % 256) == last_byte && !hit_edge) {
                /* This is OK, the guest stopped at the point of
                 * incrementing the previous page but didn't get
                 * to us yet.
                 */
                hit_edge = true;
            } else {
                fprintf(stderr, "Memory content inconsistency at %x"
                                " first_byte = %x last_byte = %x current = %x"
                                " hit_edge = %x\n",
                                address, first_byte, last_byte, b, hit_edge);
                bad = true;
            }
        }
        last_byte = b;
    }
    g_assert_false(bad);
}

static void cleanup(const char *filename)
{
    char *path = g_strdup_printf("%s/%s", tmpfs, filename);

    unlink(path);
}

static void test_migrate(void)
{
    char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
    QTestState *global = global_qtest, *from, *to;
    unsigned char dest_byte_a, dest_byte_b, dest_byte_c, dest_byte_d;
    gchar *cmd;
    QDict *rsp;

    char *bootpath = g_strdup_printf("%s/bootsect", tmpfs);
    FILE *bootfile = fopen(bootpath, "wb");

    got_stop = false;
    g_assert_cmpint(fwrite(bootsect, 512, 1, bootfile), ==, 1);
    fclose(bootfile);

    cmd = g_strdup_printf("-machine accel=kvm:tcg -m 150M"
                          " -name pcsource,debug-threads=on"
                          " -serial file:%s/src_serial"
                          " -drive file=%s,format=raw",
                          tmpfs, bootpath);
    from = qtest_start(cmd);
    g_free(cmd);

    cmd = g_strdup_printf("-machine accel=kvm:tcg -m 150M"
                          " -name pcdest,debug-threads=on"
                          " -serial file:%s/dest_serial"
                          " -drive file=%s,format=raw"
                          " -incoming %s",
                          tmpfs, bootpath, uri);
    to = qtest_init(cmd);
    g_free(cmd);

    global_qtest = from;
    rsp = qmp("{ 'execute': 'migrate-set-capabilities',"
                  "'arguments': { "
                      "'capabilities': [ {"
                          "'capability': 'postcopy-ram',"
                          "'state': true } ] } }");
    g_assert(qdict_haskey(rsp, "return"));
    QDECREF(rsp);

    global_qtest = to;
    rsp = qmp("{ 'execute': 'migrate-set-capabilities',"
                  "'arguments': { "
                      "'capabilities': [ {"
                          "'capability': 'postcopy-ram',"
                          "'state': true } ] } }");
    g_assert(qdict_haskey(rsp, "return"));
    QDECREF(rsp);

    /* We want to pick a speed slow enough that the test completes
     * quickly, but that it doesn't complete precopy even on a slow
     * machine, so also set the downtime.
     */
    global_qtest = from;
    rsp = qmp("{ 'execute': 'migrate_set_speed',"
              "'arguments': { 'value': 100000000 } }");
    g_assert(qdict_haskey(rsp, "return"));
    QDECREF(rsp);

    /* 1ms downtime - it should never finish precopy */
    rsp = qmp("{ 'execute': 'migrate_set_downtime',"
              "'arguments': { 'value': 0.001 } }");
    g_assert(qdict_haskey(rsp, "return"));
    QDECREF(rsp);


    /* Wait for the first serial output from the source */
    wait_for_serial("src_serial");

    cmd = g_strdup_printf("{ 'execute': 'migrate',"
                          "'arguments': { 'uri': '%s' } }",
                          uri);
    rsp = qmp(cmd);
    g_free(cmd);
    g_assert(qdict_haskey(rsp, "return"));
    QDECREF(rsp);

    wait_for_migration_pass();

    rsp = return_or_event(qmp("{ 'execute': 'migrate-start-postcopy' }"));
    g_assert(qdict_haskey(rsp, "return"));
    QDECREF(rsp);

    if (!got_stop) {
        qmp_eventwait("STOP");
    }

    global_qtest = to;
    qmp_eventwait("RESUME");

    wait_for_serial("dest_serial");
    global_qtest = from;
    wait_for_migration_complete();

    qtest_quit(from);

    global_qtest = to;

    qtest_memread(to, start_address, &dest_byte_a, 1);

    /* Destination still running, wait for a byte to change */
    do {
        qtest_memread(to, start_address, &dest_byte_b, 1);
        usleep(10 * 1000);
    } while (dest_byte_a == dest_byte_b);

    qmp("{ 'execute' : 'stop'}");
    /* With it stopped, check nothing changes */
    qtest_memread(to, start_address, &dest_byte_c, 1);
    sleep(1);
    qtest_memread(to, start_address, &dest_byte_d, 1);
    g_assert_cmpint(dest_byte_c, ==, dest_byte_d);

    check_guests_ram();

    qtest_quit(to);
    g_free(uri);

    global_qtest = global;

    cleanup("bootsect");
    cleanup("migsocket");
    cleanup("src_serial");
    cleanup("dest_serial");
}

int main(int argc, char **argv)
{
    char template[] = "/tmp/postcopy-test-XXXXXX";
    int ret;

    g_test_init(&argc, &argv, NULL);

    if (!ufd_version_check()) {
        return 0;
    }

    tmpfs = mkdtemp(template);
    if (!tmpfs) {
        g_test_message("mkdtemp on path (%s): %s\n", template, strerror(errno));
    }
    g_assert(tmpfs);

    module_call_init(MODULE_INIT_QOM);

    qtest_add_func("/postcopy", test_migrate);

    ret = g_test_run();

    g_assert_cmpint(ret, ==, 0);

    ret = rmdir(tmpfs);
    if (ret != 0) {
        g_test_message("unable to rmdir: path (%s): %s\n",
                       tmpfs, strerror(errno));
    }

    return ret;
}