builtin-kvm.c

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#include "builtin.h"
#include "perf.h"

#include "util/evsel.h"
#include "util/util.h"
#include "util/cache.h"
#include "util/symbol.h"
#include "util/thread.h"
#include "util/header.h"
#include "util/session.h"

#include "util/parse-options.h"
#include "util/trace-event.h"
#include "util/debug.h"
#include "util/debugfs.h"
#include "util/tool.h"
#include "util/stat.h"

#include <sys/prctl.h>

#include <semaphore.h>
#include <pthread.h>
#include <math.h>

#if defined(__i386__) || defined(__x86_64__)
#include <asm/svm.h>
#include <asm/vmx.h>
#include <asm/kvm.h>

struct event_key {
    #define INVALID_KEY     (~0ULL)
    u64 key;
    int info;
};

struct kvm_event_stats {
    u64 time;
    struct stats stats;
};

struct kvm_event {
    struct list_head hash_entry;
    struct rb_node rb;

    struct event_key key;

    struct kvm_event_stats total;

    #define DEFAULT_VCPU_NUM 8
    int max_vcpu;
    struct kvm_event_stats *vcpu;
};

typedef int (*key_cmp_fun)(struct kvm_event*, struct kvm_event*, int);

struct kvm_event_key {
    const char *name;
    key_cmp_fun key;
};


struct perf_kvm_stat;

struct kvm_events_ops {
    bool (*is_begin_event)(struct perf_evsel *evsel,
                   struct perf_sample *sample,
                   struct event_key *key);
    bool (*is_end_event)(struct perf_evsel *evsel,
                 struct perf_sample *sample, struct event_key *key);
    void (*decode_key)(struct perf_kvm_stat *kvm, struct event_key *key,
               char decode[20]);
    const char *name;
};

struct exit_reasons_table {
    unsigned long exit_code;
    const char *reason;
};

#define EVENTS_BITS     12
#define EVENTS_CACHE_SIZE   (1UL << EVENTS_BITS)

struct perf_kvm_stat {
    struct perf_tool    tool;
    struct perf_session *session;

    const char *file_name;
    const char *report_event;
    const char *sort_key;
    int trace_vcpu;

    struct exit_reasons_table *exit_reasons;
    int exit_reasons_size;
    const char *exit_reasons_isa;

    struct kvm_events_ops *events_ops;
    key_cmp_fun compare;
    struct list_head kvm_events_cache[EVENTS_CACHE_SIZE];
    u64 total_time;
    u64 total_count;

    struct rb_root result;
};


static void exit_event_get_key(struct perf_evsel *evsel,
                   struct perf_sample *sample,
                   struct event_key *key)
{
    key->info = 0;
    key->key = perf_evsel__intval(evsel, sample, "exit_reason");
}

static bool kvm_exit_event(struct perf_evsel *evsel)
{
    return !strcmp(evsel->name, "kvm:kvm_exit");
}

static bool exit_event_begin(struct perf_evsel *evsel,
                 struct perf_sample *sample, struct event_key *key)
{
    if (kvm_exit_event(evsel)) {
        exit_event_get_key(evsel, sample, key);
        return true;
    }

    return false;
}

static bool kvm_entry_event(struct perf_evsel *evsel)
{
    return !strcmp(evsel->name, "kvm:kvm_entry");
}

static bool exit_event_end(struct perf_evsel *evsel,
               struct perf_sample *sample __maybe_unused,
               struct event_key *key __maybe_unused)
{
    return kvm_entry_event(evsel);
}

static struct exit_reasons_table vmx_exit_reasons[] = {
    VMX_EXIT_REASONS
};

static struct exit_reasons_table svm_exit_reasons[] = {
    SVM_EXIT_REASONS
};

static const char *get_exit_reason(struct perf_kvm_stat *kvm, u64 exit_code)
{
    int i = kvm->exit_reasons_size;
    struct exit_reasons_table *tbl = kvm->exit_reasons;

    while (i--) {
        if (tbl->exit_code == exit_code)
            return tbl->reason;
        tbl++;
    }

    pr_err("unknown kvm exit code:%lld on %s\n",
        (unsigned long long)exit_code, kvm->exit_reasons_isa);
    return "UNKNOWN";
}

static void exit_event_decode_key(struct perf_kvm_stat *kvm,
                  struct event_key *key,
                  char decode[20])
{
    const char *exit_reason = get_exit_reason(kvm, key->key);

    scnprintf(decode, 20, "%s", exit_reason);
}

static struct kvm_events_ops exit_events = {
    .is_begin_event = exit_event_begin,
    .is_end_event = exit_event_end,
    .decode_key = exit_event_decode_key,
    .name = "VM-EXIT"
};

/*
 * For the mmio events, we treat:
 * the time of MMIO write: kvm_mmio(KVM_TRACE_MMIO_WRITE...) -> kvm_entry
 * the time of MMIO read: kvm_exit -> kvm_mmio(KVM_TRACE_MMIO_READ...).
 */
static void mmio_event_get_key(struct perf_evsel *evsel, struct perf_sample *sample,
                   struct event_key *key)
{
    key->key  = perf_evsel__intval(evsel, sample, "gpa");
    key->info = perf_evsel__intval(evsel, sample, "type");
}

#define KVM_TRACE_MMIO_READ_UNSATISFIED 0
#define KVM_TRACE_MMIO_READ 1
#define KVM_TRACE_MMIO_WRITE 2

static bool mmio_event_begin(struct perf_evsel *evsel,
                 struct perf_sample *sample, struct event_key *key)
{
    /* MMIO read begin event in kernel. */
    if (kvm_exit_event(evsel))
        return true;

    /* MMIO write begin event in kernel. */
    if (!strcmp(evsel->name, "kvm:kvm_mmio") &&
        perf_evsel__intval(evsel, sample, "type") == KVM_TRACE_MMIO_WRITE) {
        mmio_event_get_key(evsel, sample, key);
        return true;
    }

    return false;
}

static bool mmio_event_end(struct perf_evsel *evsel, struct perf_sample *sample,
               struct event_key *key)
{
    /* MMIO write end event in kernel. */
    if (kvm_entry_event(evsel))
        return true;

    /* MMIO read end event in kernel.*/
    if (!strcmp(evsel->name, "kvm:kvm_mmio") &&
        perf_evsel__intval(evsel, sample, "type") == KVM_TRACE_MMIO_READ) {
        mmio_event_get_key(evsel, sample, key);
        return true;
    }

    return false;
}

static void mmio_event_decode_key(struct perf_kvm_stat *kvm __maybe_unused,
                  struct event_key *key,
                  char decode[20])
{
    scnprintf(decode, 20, "%#lx:%s", (unsigned long)key->key,
                key->info == KVM_TRACE_MMIO_WRITE ? "W" : "R");
}

static struct kvm_events_ops mmio_events = {
    .is_begin_event = mmio_event_begin,
    .is_end_event = mmio_event_end,
    .decode_key = mmio_event_decode_key,
    .name = "MMIO Access"
};

 /* The time of emulation pio access is from kvm_pio to kvm_entry. */
static void ioport_event_get_key(struct perf_evsel *evsel,
                 struct perf_sample *sample,
                 struct event_key *key)
{
    key->key  = perf_evsel__intval(evsel, sample, "port");
    key->info = perf_evsel__intval(evsel, sample, "rw");
}

static bool ioport_event_begin(struct perf_evsel *evsel,
                   struct perf_sample *sample,
                   struct event_key *key)
{
    if (!strcmp(evsel->name, "kvm:kvm_pio")) {
        ioport_event_get_key(evsel, sample, key);
        return true;
    }

    return false;
}

static bool ioport_event_end(struct perf_evsel *evsel,
                 struct perf_sample *sample __maybe_unused,
                 struct event_key *key __maybe_unused)
{
    return kvm_entry_event(evsel);
}

static void ioport_event_decode_key(struct perf_kvm_stat *kvm __maybe_unused,
                    struct event_key *key,
                    char decode[20])
{
    scnprintf(decode, 20, "%#llx:%s", (unsigned long long)key->key,
                key->info ? "POUT" : "PIN");
}

static struct kvm_events_ops ioport_events = {
    .is_begin_event = ioport_event_begin,
    .is_end_event = ioport_event_end,
    .decode_key = ioport_event_decode_key,
    .name = "IO Port Access"
};

static bool register_kvm_events_ops(struct perf_kvm_stat *kvm)
{
    bool ret = true;

    if (!strcmp(kvm->report_event, "vmexit"))
        kvm->events_ops = &exit_events;
    else if (!strcmp(kvm->report_event, "mmio"))
        kvm->events_ops = &mmio_events;
    else if (!strcmp(kvm->report_event, "ioport"))
        kvm->events_ops = &ioport_events;
    else {
        pr_err("Unknown report event:%s\n", kvm->report_event);
        ret = false;
    }

    return ret;
}

struct vcpu_event_record {
    int vcpu_id;
    u64 start_time;
    struct kvm_event *last_event;
};


static void init_kvm_event_record(struct perf_kvm_stat *kvm)
{
    int i;

    for (i = 0; i < (int)EVENTS_CACHE_SIZE; i++)
        INIT_LIST_HEAD(&kvm->kvm_events_cache[i]);
}

static int kvm_events_hash_fn(u64 key)
{
    return key & (EVENTS_CACHE_SIZE - 1);
}

static bool kvm_event_expand(struct kvm_event *event, int vcpu_id)
{
    int old_max_vcpu = event->max_vcpu;

    if (vcpu_id < event->max_vcpu)
        return true;

    while (event->max_vcpu <= vcpu_id)
        event->max_vcpu += DEFAULT_VCPU_NUM;

    event->vcpu = realloc(event->vcpu,
                  event->max_vcpu * sizeof(*event->vcpu));
    if (!event->vcpu) {
        pr_err("Not enough memory\n");
        return false;
    }

    memset(event->vcpu + old_max_vcpu, 0,
           (event->max_vcpu - old_max_vcpu) * sizeof(*event->vcpu));
    return true;
}

static struct kvm_event *kvm_alloc_init_event(struct event_key *key)
{
    struct kvm_event *event;

    event = zalloc(sizeof(*event));
    if (!event) {
        pr_err("Not enough memory\n");
        return NULL;
    }

    event->key = *key;
    return event;
}

static struct kvm_event *find_create_kvm_event(struct perf_kvm_stat *kvm,
                           struct event_key *key)
{
    struct kvm_event *event;
    struct list_head *head;

    BUG_ON(key->key == INVALID_KEY);

    head = &kvm->kvm_events_cache[kvm_events_hash_fn(key->key)];
    list_for_each_entry(event, head, hash_entry)
        if (event->key.key == key->key && event->key.info == key->info)
            return event;

    event = kvm_alloc_init_event(key);
    if (!event)
        return NULL;

    list_add(&event->hash_entry, head);
    return event;
}

static bool handle_begin_event(struct perf_kvm_stat *kvm,
                   struct vcpu_event_record *vcpu_record,
                   struct event_key *key, u64 timestamp)
{
    struct kvm_event *event = NULL;

    if (key->key != INVALID_KEY)
        event = find_create_kvm_event(kvm, key);

    vcpu_record->last_event = event;
    vcpu_record->start_time = timestamp;
    return true;
}

static void
kvm_update_event_stats(struct kvm_event_stats *kvm_stats, u64 time_diff)
{
    kvm_stats->time += time_diff;
    update_stats(&kvm_stats->stats, time_diff);
}

static double kvm_event_rel_stddev(int vcpu_id, struct kvm_event *event)
{
    struct kvm_event_stats *kvm_stats = &event->total;

    if (vcpu_id != -1)
        kvm_stats = &event->vcpu[vcpu_id];

    return rel_stddev_stats(stddev_stats(&kvm_stats->stats),
                avg_stats(&kvm_stats->stats));
}

static bool update_kvm_event(struct kvm_event *event, int vcpu_id,
                 u64 time_diff)
{
    kvm_update_event_stats(&event->total, time_diff);

    if (!kvm_event_expand(event, vcpu_id))
        return false;

    kvm_update_event_stats(&event->vcpu[vcpu_id], time_diff);
    return true;
}

static bool handle_end_event(struct perf_kvm_stat *kvm,
                 struct vcpu_event_record *vcpu_record,
                 struct event_key *key,
                 u64 timestamp)
{
    struct kvm_event *event;
    u64 time_begin, time_diff;

    event = vcpu_record->last_event;
    time_begin = vcpu_record->start_time;

    /* The begin event is not caught. */
    if (!time_begin)
        return true;

    /*
     * In some case, the 'begin event' only records the start timestamp,
     * the actual event is recognized in the 'end event' (e.g. mmio-event).
     */

    /* Both begin and end events did not get the key. */
    if (!event && key->key == INVALID_KEY)
        return true;

    if (!event)
        event = find_create_kvm_event(kvm, key);

    if (!event)
        return false;

    vcpu_record->last_event = NULL;
    vcpu_record->start_time = 0;

    BUG_ON(timestamp < time_begin);

    time_diff = timestamp - time_begin;
    return update_kvm_event(event, vcpu_record->vcpu_id, time_diff);
}

static
struct vcpu_event_record *per_vcpu_record(struct thread *thread,
                      struct perf_evsel *evsel,
                      struct perf_sample *sample)
{
    /* Only kvm_entry records vcpu id. */
    if (!thread->priv && kvm_entry_event(evsel)) {
        struct vcpu_event_record *vcpu_record;

        vcpu_record = zalloc(sizeof(*vcpu_record));
        if (!vcpu_record) {
            pr_err("%s: Not enough memory\n", __func__);
            return NULL;
        }

        vcpu_record->vcpu_id = perf_evsel__intval(evsel, sample, "vcpu_id");
        thread->priv = vcpu_record;
    }

    return thread->priv;
}

static bool handle_kvm_event(struct perf_kvm_stat *kvm,
                 struct thread *thread,
                 struct perf_evsel *evsel,
                 struct perf_sample *sample)
{
    struct vcpu_event_record *vcpu_record;
    struct event_key key = {.key = INVALID_KEY};

    vcpu_record = per_vcpu_record(thread, evsel, sample);
    if (!vcpu_record)
        return true;

    if (kvm->events_ops->is_begin_event(evsel, sample, &key))
        return handle_begin_event(kvm, vcpu_record, &key, sample->time);

    if (kvm->events_ops->is_end_event(evsel, sample, &key))
        return handle_end_event(kvm, vcpu_record, &key, sample->time);

    return true;
}

#define GET_EVENT_KEY(func, field)                  \
static u64 get_event_ ##func(struct kvm_event *event, int vcpu)     \
{                                   \
    if (vcpu == -1)                         \
        return event->total.field;              \
                                    \
    if (vcpu >= event->max_vcpu)                    \
        return 0;                       \
                                    \
    return event->vcpu[vcpu].field;                 \
}

#define COMPARE_EVENT_KEY(func, field)                  \
GET_EVENT_KEY(func, field)                      \
static int compare_kvm_event_ ## func(struct kvm_event *one,        \
                    struct kvm_event *two, int vcpu)\
{                                   \
    return get_event_ ##func(one, vcpu) >               \
                get_event_ ##func(two, vcpu);       \
}

GET_EVENT_KEY(time, time);
COMPARE_EVENT_KEY(count, stats.n);
COMPARE_EVENT_KEY(mean, stats.mean);

#define DEF_SORT_NAME_KEY(name, compare_key)                \
    { #name, compare_kvm_event_ ## compare_key }

static struct kvm_event_key keys[] = {
    DEF_SORT_NAME_KEY(sample, count),
    DEF_SORT_NAME_KEY(time, mean),
    { NULL, NULL }
};

static bool select_key(struct perf_kvm_stat *kvm)
{
    int i;

    for (i = 0; keys[i].name; i++) {
        if (!strcmp(keys[i].name, kvm->sort_key)) {
            kvm->compare = keys[i].key;
            return true;
        }
    }

    pr_err("Unknown compare key:%s\n", kvm->sort_key);
    return false;
}

static void insert_to_result(struct rb_root *result, struct kvm_event *event,
                 key_cmp_fun bigger, int vcpu)
{
    struct rb_node **rb = &result->rb_node;
    struct rb_node *parent = NULL;
    struct kvm_event *p;

    while (*rb) {
        p = container_of(*rb, struct kvm_event, rb);
        parent = *rb;

        if (bigger(event, p, vcpu))
            rb = &(*rb)->rb_left;
        else
            rb = &(*rb)->rb_right;
    }

    rb_link_node(&event->rb, parent, rb);
    rb_insert_color(&event->rb, result);
}

static void
update_total_count(struct perf_kvm_stat *kvm, struct kvm_event *event)
{
    int vcpu = kvm->trace_vcpu;

    kvm->total_count += get_event_count(event, vcpu);
    kvm->total_time += get_event_time(event, vcpu);
}

static bool event_is_valid(struct kvm_event *event, int vcpu)
{
    return !!get_event_count(event, vcpu);
}

static void sort_result(struct perf_kvm_stat *kvm)
{
    unsigned int i;
    int vcpu = kvm->trace_vcpu;
    struct kvm_event *event;

    for (i = 0; i < EVENTS_CACHE_SIZE; i++)
        list_for_each_entry(event, &kvm->kvm_events_cache[i], hash_entry)
            if (event_is_valid(event, vcpu)) {
                update_total_count(kvm, event);
                insert_to_result(&kvm->result, event,
                         kvm->compare, vcpu);
            }
}

/* returns left most element of result, and erase it */
static struct kvm_event *pop_from_result(struct rb_root *result)
{
    struct rb_node *node = rb_first(result);

    if (!node)
        return NULL;

    rb_erase(node, result);
    return container_of(node, struct kvm_event, rb);
}

static void print_vcpu_info(int vcpu)
{
    pr_info("Analyze events for ");

    if (vcpu == -1)
        pr_info("all VCPUs:\n\n");
    else
        pr_info("VCPU %d:\n\n", vcpu);
}

static void print_result(struct perf_kvm_stat *kvm)
{
    char decode[20];
    struct kvm_event *event;
    int vcpu = kvm->trace_vcpu;

    pr_info("\n\n");
    print_vcpu_info(vcpu);
    pr_info("%20s ", kvm->events_ops->name);
    pr_info("%10s ", "Samples");
    pr_info("%9s ", "Samples%");

    pr_info("%9s ", "Time%");
    pr_info("%16s ", "Avg time");
    pr_info("\n\n");

    while ((event = pop_from_result(&kvm->result))) {
        u64 ecount, etime;

        ecount = get_event_count(event, vcpu);
        etime = get_event_time(event, vcpu);

        kvm->events_ops->decode_key(kvm, &event->key, decode);
        pr_info("%20s ", decode);
        pr_info("%10llu ", (unsigned long long)ecount);
        pr_info("%8.2f%% ", (double)ecount / kvm->total_count * 100);
        pr_info("%8.2f%% ", (double)etime / kvm->total_time * 100);
        pr_info("%9.2fus ( +-%7.2f%% )", (double)etime / ecount/1e3,
            kvm_event_rel_stddev(vcpu, event));
        pr_info("\n");
    }

    pr_info("\nTotal Samples:%lld, Total events handled time:%.2fus.\n\n",
        (unsigned long long)kvm->total_count, kvm->total_time / 1e3);
}

static int process_sample_event(struct perf_tool *tool,
                union perf_event *event,
                struct perf_sample *sample,
                struct perf_evsel *evsel,
                struct machine *machine)
{
    struct thread *thread = machine__findnew_thread(machine, sample->tid);
    struct perf_kvm_stat *kvm = container_of(tool, struct perf_kvm_stat,
                         tool);

    if (thread == NULL) {
        pr_debug("problem processing %d event, skipping it.\n",
            event->header.type);
        return -1;
    }

    if (!handle_kvm_event(kvm, thread, evsel, sample))
        return -1;

    return 0;
}

static int get_cpu_isa(struct perf_session *session)
{
    char *cpuid = session->header.env.cpuid;
    int isa;

    if (strstr(cpuid, "Intel"))
        isa = 1;
    else if (strstr(cpuid, "AMD"))
        isa = 0;
    else {
        pr_err("CPU %s is not supported.\n", cpuid);
        isa = -ENOTSUP;
    }

    return isa;
}

static int read_events(struct perf_kvm_stat *kvm)
{
    int ret;

    struct perf_tool eops = {
        .sample         = process_sample_event,
        .comm           = perf_event__process_comm,
        .ordered_samples    = true,
    };

    kvm->tool = eops;
    kvm->session = perf_session__new(kvm->file_name, O_RDONLY, 0, false,
                     &kvm->tool);
    if (!kvm->session) {
        pr_err("Initializing perf session failed\n");
        return -EINVAL;
    }

    if (!perf_session__has_traces(kvm->session, "kvm record"))
        return -EINVAL;

    /*
     * Do not use 'isa' recorded in kvm_exit tracepoint since it is not
     * traced in the old kernel.
     */
    ret = get_cpu_isa(kvm->session);

    if (ret < 0)
        return ret;

    if (ret == 1) {
        kvm->exit_reasons = vmx_exit_reasons;
        kvm->exit_reasons_size = ARRAY_SIZE(vmx_exit_reasons);
        kvm->exit_reasons_isa = "VMX";
    }

    return perf_session__process_events(kvm->session, &kvm->tool);
}

static bool verify_vcpu(int vcpu)
{
    if (vcpu != -1 && vcpu < 0) {
        pr_err("Invalid vcpu:%d.\n", vcpu);
        return false;
    }

    return true;
}

static int kvm_events_report_vcpu(struct perf_kvm_stat *kvm)
{
    int ret = -EINVAL;
    int vcpu = kvm->trace_vcpu;

    if (!verify_vcpu(vcpu))
        goto exit;

    if (!select_key(kvm))
        goto exit;

    if (!register_kvm_events_ops(kvm))
        goto exit;

    init_kvm_event_record(kvm);
    setup_pager();

    ret = read_events(kvm);
    if (ret)
        goto exit;

    sort_result(kvm);
    print_result(kvm);

exit:
    return ret;
}

static const char * const record_args[] = {
    "record",
    "-R",
    "-f",
    "-m", "1024",
    "-c", "1",
    "-e", "kvm:kvm_entry",
    "-e", "kvm:kvm_exit",
    "-e", "kvm:kvm_mmio",
    "-e", "kvm:kvm_pio",
};

#define STRDUP_FAIL_EXIT(s)     \
    ({  char *_p;       \
    _p = strdup(s);     \
        if (!_p)        \
            return -ENOMEM; \
        _p;         \
    })

static int
kvm_events_record(struct perf_kvm_stat *kvm, int argc, const char **argv)
{
    unsigned int rec_argc, i, j;
    const char **rec_argv;

    rec_argc = ARRAY_SIZE(record_args) + argc + 2;
    rec_argv = calloc(rec_argc + 1, sizeof(char *));

    if (rec_argv == NULL)
        return -ENOMEM;

    for (i = 0; i < ARRAY_SIZE(record_args); i++)
        rec_argv[i] = STRDUP_FAIL_EXIT(record_args[i]);

    rec_argv[i++] = STRDUP_FAIL_EXIT("-o");
    rec_argv[i++] = STRDUP_FAIL_EXIT(kvm->file_name);

    for (j = 1; j < (unsigned int)argc; j++, i++)
        rec_argv[i] = argv[j];

    return cmd_record(i, rec_argv, NULL);
}

static int
kvm_events_report(struct perf_kvm_stat *kvm, int argc, const char **argv)
{
    const struct option kvm_events_report_options[] = {
        OPT_STRING(0, "event", &kvm->report_event, "report event",
                "event for reporting: vmexit, mmio, ioport"),
        OPT_INTEGER(0, "vcpu", &kvm->trace_vcpu,
                "vcpu id to report"),
        OPT_STRING('k', "key", &kvm->sort_key, "sort-key",
                "key for sorting: sample(sort by samples number)"
                " time (sort by avg time)"),
        OPT_END()
    };

    const char * const kvm_events_report_usage[] = {
        "perf kvm stat report [<options>]",
        NULL
    };

    symbol__init();

    if (argc) {
        argc = parse_options(argc, argv,
                     kvm_events_report_options,
                     kvm_events_report_usage, 0);
        if (argc)
            usage_with_options(kvm_events_report_usage,
                       kvm_events_report_options);
    }

    return kvm_events_report_vcpu(kvm);
}

static void print_kvm_stat_usage(void)
{
    printf("Usage: perf kvm stat <command>\n\n");

    printf("# Available commands:\n");
    printf("\trecord: record kvm events\n");
    printf("\treport: report statistical data of kvm events\n");

    printf("\nOtherwise, it is the alias of 'perf stat':\n");
}

static int kvm_cmd_stat(const char *file_name, int argc, const char **argv)
{
    struct perf_kvm_stat kvm = {
        .file_name = file_name,

        .trace_vcpu = -1,
        .report_event   = "vmexit",
        .sort_key   = "sample",

        .exit_reasons = svm_exit_reasons,
        .exit_reasons_size = ARRAY_SIZE(svm_exit_reasons),
        .exit_reasons_isa = "SVM",
    };

    if (argc == 1) {
        print_kvm_stat_usage();
        goto perf_stat;
    }

    if (!strncmp(argv[1], "rec", 3))
        return kvm_events_record(&kvm, argc - 1, argv + 1);

    if (!strncmp(argv[1], "rep", 3))
        return kvm_events_report(&kvm, argc - 1 , argv + 1);

perf_stat:
    return cmd_stat(argc, argv, NULL);
}
#endif

static int __cmd_record(const char *file_name, int argc, const char **argv)
{
    int rec_argc, i = 0, j;
    const char **rec_argv;

    rec_argc = argc + 2;
    rec_argv = calloc(rec_argc + 1, sizeof(char *));
    rec_argv[i++] = strdup("record");
    rec_argv[i++] = strdup("-o");
    rec_argv[i++] = strdup(file_name);
    for (j = 1; j < argc; j++, i++)
        rec_argv[i] = argv[j];

    BUG_ON(i != rec_argc);

    return cmd_record(i, rec_argv, NULL);
}

static int __cmd_report(const char *file_name, int argc, const char **argv)
{
    int rec_argc, i = 0, j;
    const char **rec_argv;

    rec_argc = argc + 2;
    rec_argv = calloc(rec_argc + 1, sizeof(char *));
    rec_argv[i++] = strdup("report");
    rec_argv[i++] = strdup("-i");
    rec_argv[i++] = strdup(file_name);
    for (j = 1; j < argc; j++, i++)
        rec_argv[i] = argv[j];

    BUG_ON(i != rec_argc);

    return cmd_report(i, rec_argv, NULL);
}

static int
__cmd_buildid_list(const char *file_name, int argc, const char **argv)
{
    int rec_argc, i = 0, j;
    const char **rec_argv;

    rec_argc = argc + 2;
    rec_argv = calloc(rec_argc + 1, sizeof(char *));
    rec_argv[i++] = strdup("buildid-list");
    rec_argv[i++] = strdup("-i");
    rec_argv[i++] = strdup(file_name);
    for (j = 1; j < argc; j++, i++)
        rec_argv[i] = argv[j];

    BUG_ON(i != rec_argc);

    return cmd_buildid_list(i, rec_argv, NULL);
}

int cmd_kvm(int argc, const char **argv, const char *prefix __maybe_unused)
{
    const char *file_name;

    const struct option kvm_options[] = {
        OPT_STRING('i', "input", &file_name, "file",
               "Input file name"),
        OPT_STRING('o', "output", &file_name, "file",
               "Output file name"),
        OPT_BOOLEAN(0, "guest", &perf_guest,
                "Collect guest os data"),
        OPT_BOOLEAN(0, "host", &perf_host,
                "Collect host os data"),
        OPT_STRING(0, "guestmount", &symbol_conf.guestmount, "directory",
               "guest mount directory under which every guest os"
               " instance has a subdir"),
        OPT_STRING(0, "guestvmlinux", &symbol_conf.default_guest_vmlinux_name,
               "file", "file saving guest os vmlinux"),
        OPT_STRING(0, "guestkallsyms", &symbol_conf.default_guest_kallsyms,
               "file", "file saving guest os /proc/kallsyms"),
        OPT_STRING(0, "guestmodules", &symbol_conf.default_guest_modules,
               "file", "file saving guest os /proc/modules"),
        OPT_END()
    };


    const char * const kvm_usage[] = {
        "perf kvm [<options>] {top|record|report|diff|buildid-list|stat}",
        NULL
    };

    perf_host  = 0;
    perf_guest = 1;

    argc = parse_options(argc, argv, kvm_options, kvm_usage,
            PARSE_OPT_STOP_AT_NON_OPTION);
    if (!argc)
        usage_with_options(kvm_usage, kvm_options);

    if (!perf_host)
        perf_guest = 1;

    if (!file_name) {
        if (perf_host && !perf_guest)
            file_name = strdup("perf.data.host");
        else if (!perf_host && perf_guest)
            file_name = strdup("perf.data.guest");
        else
            file_name = strdup("perf.data.kvm");

        if (!file_name) {
            pr_err("Failed to allocate memory for filename\n");
            return -ENOMEM;
        }
    }

    if (!strncmp(argv[0], "rec", 3))
        return __cmd_record(file_name, argc, argv);
    else if (!strncmp(argv[0], "rep", 3))
        return __cmd_report(file_name, argc, argv);
    else if (!strncmp(argv[0], "diff", 4))
        return cmd_diff(argc, argv, NULL);
    else if (!strncmp(argv[0], "top", 3))
        return cmd_top(argc, argv, NULL);
    else if (!strncmp(argv[0], "buildid-list", 12))
        return __cmd_buildid_list(file_name, argc, argv);
#if defined(__i386__) || defined(__x86_64__)
    else if (!strncmp(argv[0], "stat", 4))
        return kvm_cmd_stat(file_name, argc, argv);
#endif
    else
        usage_with_options(kvm_usage, kvm_options);

    return 0;
}