Re: [Qemu-devel] [PATCH 3/3] target/s390x: implement serialization in BRANCH CONDITION

[Richard Henderson]

On 05/09/2017 01:28 AM, Aurelien Jarno wrote:
> Signed-off-by: Aurelien Jarno <address@hidden>
> ---
>   target/s390x/translate.c | 15 +++++++++++++++
>   1 file changed, 15 insertions(+)
>
> diff --git a/target/s390x/translate.c b/target/s390x/translate.c
> index c58c27f8e9..2f07ce2be9 100644
> --- a/target/s390x/translate.c
> +++ b/target/s390x/translate.c
> @@ -1517,6 +1517,21 @@ static ExitStatus op_bc(DisasContext *s, DisasOps *o)
>       int imm = is_imm ? get_field(s->fields, i2) : 0;
>       DisasCompare c;
>   
> +    /* BCR with R2 = 0 causes no branching */
> +    if (have_field(s->fields, r2) && get_field(s->fields, r2) == 0) {
> +        if (m1 == 14) {
> +            /* Perform serialization */
> +            /* FIXME: check for fast-BCR-serialization facility */
> +            tcg_gen_mb(TCG_MO_ALL | TCG_BAR_SC);
> +        }
> +        if (m1 == 15) {
> +            /* Perform serialization */
> +            /* FIXME: perform checkpoint-synchronisation */

I don't know if we'll ever need to do anything with this side effect, but I 
guess it's good to document.

Reviewed-by: Richard Henderson <address@hidden>


r~