Re: [PATCH v2 23/28] target/s390x: Remove use_exit_tb

[David Hildenbrand]

On 30.06.21 20:32, Richard Henderson wrote:
> We have not needed to end a TB for I/O since ba3e7926691
> ("icount: clean up cpu_can_io at the entry to the block").
>
> In use_goto_tb, the check for singlestep_enabled is in the
> generic translator_use_goto_tb.  In s390x_tr_tb_stop, the
> check for singlestep_enabled is in the preceeding do_debug test.

s/preceeding/preceding/

> Which leaves only FLAG_MASK_PER: fold that test alone into
> the two callers of use_exit tb.
>
> Cc: David Hildenbrand <david@redhat.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   target/s390x/translate.c | 11 ++---------
>   1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/target/s390x/translate.c b/target/s390x/translate.c
> index 117a890ecd..4742f59ca9 100644
> --- a/target/s390x/translate.c
> +++ b/target/s390x/translate.c
> @@ -685,16 +685,9 @@ static void gen_op_calc_cc(DisasContext *s)
>       set_cc_static(s);
>   }
>   
> -static bool use_exit_tb(DisasContext *s)
> -{
> -    return s->base.singlestep_enabled ||
> -            (tb_cflags(s->base.tb) & CF_LAST_IO) ||
> -            (s->base.tb->flags & FLAG_MASK_PER);
> -}
> -
>   static bool use_goto_tb(DisasContext *s, uint64_t dest)
>   {
> -    if (unlikely(use_exit_tb(s))) {
> +    if (unlikely(s->base.tb->flags & FLAG_MASK_PER)) {
>           return false;
>       }
>       return translator_use_goto_tb(&s->base, dest);
> @@ -6634,7 +6627,7 @@ static void s390x_tr_tb_stop(DisasContextBase *dcbase, 
> CPUState *cs)
>           /* Exit the TB, either by raising a debug exception or by return.  */
>           if (dc->do_debug) {
>               gen_exception(EXCP_DEBUG);
> -        } else if (use_exit_tb(dc) ||
> +        } else if ((dc->base.tb->flags & FLAG_MASK_PER) ||
>                      dc->base.is_jmp == DISAS_PC_STALE_NOCHAIN) {
>               tcg_gen_exit_tb(NULL, 0);
>           } else {

Reviewed-by: David Hildenbrand <david@redhat.com>

--
Thanks,

David / dhildenb