Re: [Qemu-devel] [RFC v2 PATCH 08/13] tcg/s390: Add support for fence

[Sergey Fedorov <serge.fdrv@gmail.com>]

On 31/05/16 21:39, Pranith Kumar wrote:
> Cc: Alexander Graf <agraf@suse.de>
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
> ---
>  tcg/s390/tcg-target.inc.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/tcg/s390/tcg-target.inc.c b/tcg/s390/tcg-target.inc.c
> index e95b04b..b4f14bc 100644
> --- a/tcg/s390/tcg-target.inc.c
> +++ b/tcg/s390/tcg-target.inc.c
> @@ -341,6 +341,7 @@ static tcg_insn_unit *tb_ret_addr;
>  #define FACILITY_EXT_IMM	(1ULL << (63 - 21))
>  #define FACILITY_GEN_INST_EXT	(1ULL << (63 - 34))
>  #define FACILITY_LOAD_ON_COND   (1ULL << (63 - 45))
> +#define FACILITY_FAST_BCR_SER   FACILITY_LOAD_ON_COND
>  
>  static uint64_t facilities;
>  
> @@ -2157,6 +2158,13 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
>          tgen_deposit(s, args[0], args[2], args[3], args[4]);
>          break;
>  
> +    case INDEX_op_mb:
> +        /* The host memory model is quite strong, we simply need to
> +           serialize the instruction stream.  */
> +        tcg_out_insn(s, RR, BCR,
> +		     facilities & FACILITY_FAST_BCR_SER ? 14 : 15, 0);
> +        break;
> +

Do we? What does that mean?

Kind regards,
Sergey

>      case INDEX_op_mov_i32:  /* Always emitted via tcg_out_mov.  */
>      case INDEX_op_mov_i64:
>      case INDEX_op_movi_i32: /* Always emitted via tcg_out_movi.  */
> @@ -2278,6 +2286,7 @@ static const TCGTargetOpDef s390_op_defs[] = {
>      { INDEX_op_movcond_i64, { "r", "r", "rC", "r", "0" } },
>      { INDEX_op_deposit_i64, { "r", "0", "r" } },
>  
> +    { INDEX_op_mb, { "r" } },
>      { -1 },
>  };
>