Re: [PATCH v6 05/25] target/riscv: Add a tb flags field for vstart

[Alistair Francis]

On Sat, Mar 25, 2023 at 9:52 PM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> From: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
>
> Once we mistook the vstart directly from the env->vstart. As env->vstart is 
> not
> a constant, we should record it in the tb flags if we want to use
> it in translation.
>
> Reported-by: Richard Henderson <richard.henderson@linaro.org>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
> Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
> Message-Id: <20230324143031.1093-5-zhiwei_liu@linux.alibaba.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/cpu.h                      |  1 +
>  target/riscv/cpu_helper.c               |  1 +
>  target/riscv/translate.c                |  4 ++--
>  target/riscv/insn_trans/trans_rvv.c.inc | 14 +++++++-------
>  4 files changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index d9e0eaaf9b..86a82e25dc 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -657,6 +657,7 @@ FIELD(TB_FLAGS, VMA, 21, 1)
>  FIELD(TB_FLAGS, ITRIGGER, 22, 1)
>  /* Virtual mode enabled */
>  FIELD(TB_FLAGS, VIRT_ENABLED, 23, 1)
> +FIELD(TB_FLAGS, VSTART_EQ_ZERO, 24, 1)
>
>  #ifdef TARGET_RISCV32
>  #define riscv_cpu_mxl(env)  ((void)(env), MXL_RV32)
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index 4fdd6fe021..4f0999d50b 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -74,6 +74,7 @@ void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong 
> *pc,
>                      FIELD_EX64(env->vtype, VTYPE, VTA));
>          flags = FIELD_DP32(flags, TB_FLAGS, VMA,
>                      FIELD_EX64(env->vtype, VTYPE, VMA));
> +        flags = FIELD_DP32(flags, TB_FLAGS, VSTART_EQ_ZERO, env->vstart == 
> 0);
>      } else {
>          flags = FIELD_DP32(flags, TB_FLAGS, VILL, 1);
>      }
> diff --git a/target/riscv/translate.c b/target/riscv/translate.c
> index 74d0b9889d..f8c077525c 100644
> --- a/target/riscv/translate.c
> +++ b/target/riscv/translate.c
> @@ -97,7 +97,7 @@ typedef struct DisasContext {
>      uint8_t vta;
>      uint8_t vma;
>      bool cfg_vta_all_1s;
> -    target_ulong vstart;
> +    bool vstart_eq_zero;
>      bool vl_eq_vlmax;
>      CPUState *cs;
>      TCGv zero;
> @@ -1155,7 +1155,7 @@ static void 
> riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)
>      ctx->vta = FIELD_EX32(tb_flags, TB_FLAGS, VTA) && cpu->cfg.rvv_ta_all_1s;
>      ctx->vma = FIELD_EX32(tb_flags, TB_FLAGS, VMA) && cpu->cfg.rvv_ma_all_1s;
>      ctx->cfg_vta_all_1s = cpu->cfg.rvv_ta_all_1s;
> -    ctx->vstart = env->vstart;
> +    ctx->vstart_eq_zero = FIELD_EX32(tb_flags, TB_FLAGS, VSTART_EQ_ZERO);
>      ctx->vl_eq_vlmax = FIELD_EX32(tb_flags, TB_FLAGS, VL_EQ_VLMAX);
>      ctx->misa_mxl_max = env->misa_mxl_max;
>      ctx->xl = FIELD_EX32(tb_flags, TB_FLAGS, XL);
> diff --git a/target/riscv/insn_trans/trans_rvv.c.inc 
> b/target/riscv/insn_trans/trans_rvv.c.inc
> index 6297c3b50d..32b3b9a8e5 100644
> --- a/target/riscv/insn_trans/trans_rvv.c.inc
> +++ b/target/riscv/insn_trans/trans_rvv.c.inc
> @@ -547,7 +547,7 @@ static bool vext_check_sds(DisasContext *s, int vd, int 
> vs1, int vs2, int vm)
>   */
>  static bool vext_check_reduction(DisasContext *s, int vs2)
>  {
> -    return require_align(vs2, s->lmul) && (s->vstart == 0);
> +    return require_align(vs2, s->lmul) && s->vstart_eq_zero;
>  }
>
>  /*
> @@ -3083,7 +3083,7 @@ static bool trans_vcpop_m(DisasContext *s, arg_rmr *a)
>  {
>      if (require_rvv(s) &&
>          vext_check_isa_ill(s) &&
> -        s->vstart == 0) {
> +        s->vstart_eq_zero) {
>          TCGv_ptr src2, mask;
>          TCGv dst;
>          TCGv_i32 desc;
> @@ -3112,7 +3112,7 @@ static bool trans_vfirst_m(DisasContext *s, arg_rmr *a)
>  {
>      if (require_rvv(s) &&
>          vext_check_isa_ill(s) &&
> -        s->vstart == 0) {
> +        s->vstart_eq_zero) {
>          TCGv_ptr src2, mask;
>          TCGv dst;
>          TCGv_i32 desc;
> @@ -3146,7 +3146,7 @@ static bool trans_##NAME(DisasContext *s, arg_rmr *a)   
>            \
>          vext_check_isa_ill(s) &&                                   \
>          require_vm(a->vm, a->rd) &&                                \
>          (a->rd != a->rs2) &&                                       \
> -        (s->vstart == 0)) {                                        \
> +        s->vstart_eq_zero) {                                       \
>          uint32_t data = 0;                                         \
>          gen_helper_gvec_3_ptr *fn = gen_helper_##NAME;             \
>          TCGLabel *over = gen_new_label();                          \
> @@ -3187,7 +3187,7 @@ static bool trans_viota_m(DisasContext *s, arg_viota_m 
> *a)
>          !is_overlapped(a->rd, 1 << MAX(s->lmul, 0), a->rs2, 1) &&
>          require_vm(a->vm, a->rd) &&
>          require_align(a->rd, s->lmul) &&
> -        (s->vstart == 0)) {
> +        s->vstart_eq_zero) {
>          uint32_t data = 0;
>          TCGLabel *over = gen_new_label();
>          tcg_gen_brcondi_tl(TCG_COND_EQ, cpu_vl, 0, over);
> @@ -3636,7 +3636,7 @@ static bool vcompress_vm_check(DisasContext *s, arg_r 
> *a)
>             require_align(a->rs2, s->lmul) &&
>             (a->rd != a->rs2) &&
>             !is_overlapped(a->rd, 1 << MAX(s->lmul, 0), a->rs1, 1) &&
> -           (s->vstart == 0);
> +           s->vstart_eq_zero;
>  }
>
>  static bool trans_vcompress_vm(DisasContext *s, arg_r *a)
> @@ -3675,7 +3675,7 @@ static bool trans_##NAME(DisasContext *s, arg_##NAME * 
> a)               \
>          QEMU_IS_ALIGNED(a->rd, LEN) &&                                  \
>          QEMU_IS_ALIGNED(a->rs2, LEN)) {                                 \
>          uint32_t maxsz = (s->cfg_ptr->vlen >> 3) * LEN;                 \
> -        if (s->vstart == 0) {                                           \
> +        if (s->vstart_eq_zero) {                                        \
>              /* EEW = 8 */                                               \
>              tcg_gen_gvec_mov(MO_8, vreg_ofs(s, a->rd),                  \
>                               vreg_ofs(s, a->rs2), maxsz, maxsz);        \
> --
> 2.34.1
>
>