Re: [PATCH v2 22/40] test/plugins: preserve the instruction record over translations

[Manos Pitsidianakis]

On Fri, 5 Jul 2024 at 11:43, Alex Bennée <alex.bennee@linaro.org> wrote:
>
> We are interested in the particular instruction so we should use a
> stable record for it. We could bring this down to physical address but
> for now vaddr + disas seems to do the trick.
>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> ---
>  tests/plugin/insn.c | 76 ++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 71 insertions(+), 5 deletions(-)
>
> diff --git a/tests/plugin/insn.c b/tests/plugin/insn.c
> index 524f9ddde8..baf2d07205 100644
> --- a/tests/plugin/insn.c
> +++ b/tests/plugin/insn.c
> @@ -43,6 +43,44 @@ typedef struct {
>      char *disas;
>  } Instruction;
>
> +/* A hash table to hold matched instructions */
> +static GHashTable *match_insn_records;
> +static GMutex match_hash_lock;
> +
> +
> +static Instruction * get_insn_record(const char *disas, uint64_t vaddr, 
> Match *m)
> +{
> +    g_autofree char *str_hash = g_strdup_printf("%"PRIx64" %s", vaddr, 
> disas);
> +    Instruction *record;
> +
> +    g_mutex_lock(&match_hash_lock);
> +
> +    if (!match_insn_records) {
> +        match_insn_records = g_hash_table_new(g_str_hash, g_str_equal);
> +    }
> +
> +    record = g_hash_table_lookup(match_insn_records, str_hash);
> +
> +    if (!record) {
> +        g_autoptr(GString) ts = g_string_new(str_hash);
> +
> +        record = g_new0(Instruction, 1);
> +        record->disas = g_strdup(disas);
> +        record->vaddr = vaddr;
> +        record->match = m;
> +
> +        g_hash_table_insert(match_insn_records, str_hash, record);
> +
> +        g_string_prepend(ts, "Created record for: ");
> +        g_string_append(ts, "\n");
> +        qemu_plugin_outs(ts->str);
> +    }
> +
> +    g_mutex_unlock(&match_hash_lock);
> +
> +    return record;
> +}
> +
>  /*
>   * Initialise a new vcpu with reading the register list
>   */
> @@ -131,16 +169,19 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct 
> qemu_plugin_tb *tb)
>           * If we are tracking certain instructions we will need more
>           * information about the instruction which we also need to
>           * save if there is a hit.
> +         *
> +         * We only want one record for each occurrence of the matched
> +         * instruction.
>           */
>          if (matches->len) {
>              char *insn_disas = qemu_plugin_insn_disas(insn);
>              for (int j = 0; j < matches->len; j++) {
>                  Match *m = &g_array_index(matches, Match, j);
>                  if (g_str_has_prefix(insn_disas, m->match_string)) {
> -                    Instruction *rec = g_new0(Instruction, 1);
> -                    rec->disas = g_strdup(insn_disas);
> -                    rec->vaddr = qemu_plugin_insn_vaddr(insn);
> -                    rec->match = m;
> +                    Instruction *rec = get_insn_record(insn_disas,
> +                                                       
> qemu_plugin_insn_vaddr(insn),
> +                                                       m);
> +
>                      qemu_plugin_register_vcpu_insn_exec_cb(
>                          insn, vcpu_insn_matched_exec_before,
>                          QEMU_PLUGIN_CB_NO_REGS, rec);
> @@ -173,13 +214,38 @@ static void plugin_exit(qemu_plugin_id_t id, void *p)
>                                 qemu_plugin_u64_sum(insn_count));
>      }
>      qemu_plugin_outs(out->str);
> -
>      qemu_plugin_scoreboard_free(insn_count.score);
> +
> +    g_mutex_lock(&match_hash_lock);
> +
>      for (i = 0; i < matches->len; ++i) {
>          Match *m = &g_array_index(matches, Match, i);
> +        GHashTableIter iter;
> +        Instruction *record;
> +        qemu_plugin_u64 hit_e = 
> qemu_plugin_scoreboard_u64_in_struct(m->counts, MatchCount, hits);
> +        uint64_t hits = qemu_plugin_u64_sum(hit_e);
> +
> +        g_string_printf(out, "Match: %s, hits %"PRId64"\n", m->match_string, 
> hits);
> +        qemu_plugin_outs(out->str);
> +
> +        g_hash_table_iter_init(&iter, match_insn_records);
> +        while (g_hash_table_iter_next(&iter, NULL, (void **)&record)) {
> +            if (record->match == m) {
> +                g_string_printf(out,
> +                                "  %"PRIx64": %s (hits %"PRId64")\n",
> +                                record->vaddr,
> +                                record->disas,
> +                                record->hits);
> +                qemu_plugin_outs(out->str);
> +            }
> +        }
> +
>          g_free(m->match_string);
>          qemu_plugin_scoreboard_free(m->counts);
>      }
> +
> +    g_mutex_unlock(&match_hash_lock);
> +
>      g_array_free(matches, TRUE);
>      g_array_free(sizes, TRUE);
>  }
> --
> 2.39.2

Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>