Re: [PATCH v6] target/loongarch: fix vldi/xvldi raise wrong error

[Bibo Mao]

It will be better if check_vldi_mode() is renamed as 
check_valid_vldi_mode().

Reviewed-by: Bibo Mao <maobibo@loongson.cn>

On 2025/6/18 下午3:49, gaosong wrote:
> Ping ! :-)
> 在 2025/6/5 上午9:53, Song Gao 写道:
> > on qemu we got an aborted error
> > **
> > ERROR:../target/loongarch/tcg/insn_trans/trans_vec.c.inc:3574:vldi_get_value: 
> > code should not be reached
> > Bail out! 
> > ERROR:../target/loongarch/tcg/insn_trans/trans_vec.c.inc:3574:vldi_get_value: 
> > code should not be reached
> > Aborted (core dumped)
> > but on 3A600/3A5000 we got a "Illegal instruction" error.
> >
> > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2971
> >
> > Fixes: 29bb5d727ff ("target/loongarch: Implement vldi")
> >   Cc: qemu-stable@nongnu.org
> > Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> > Signed-off-by: Song Gao <gaosong@loongson.cn>
> > ---
> >   target/loongarch/tcg/insn_trans/trans_vec.c.inc | 13 +++++++++++--
> >   1 file changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/target/loongarch/tcg/insn_trans/trans_vec.c.inc 
> > b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
> > index dff92772ad..7e50fa7541 100644
> > --- a/target/loongarch/tcg/insn_trans/trans_vec.c.inc
> > +++ b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
> > @@ -3465,7 +3465,7 @@ TRANS(xvmsknz_b, LASX, gen_xx, gen_helper_vmsknz_b)
> >   static uint64_t vldi_get_value(DisasContext *ctx, uint32_t imm)
> >   {
> >       int mode;
> > -    uint64_t data, t;
> > +    uint64_t data = 0, t;
> >       /*
> >        * imm bit [11:8] is mode, mode value is 0-12.
> > @@ -3570,17 +3570,26 @@ static uint64_t vldi_get_value(DisasContext 
> > *ctx, uint32_t imm)
> >           }
> >           break;
> >       default:
> > -        generate_exception(ctx, EXCCODE_INE);
> >           g_assert_not_reached();
> >       }
> >       return data;
> >   }
> > +static bool check_vldi_mode(arg_vldi *a)
> > +{
> > +   return  extract32(a->imm, 8, 4) <= 12;
> > +}
> > +
> >   static bool gen_vldi(DisasContext *ctx, arg_vldi *a, uint32_t oprsz)
> >   {
> >       int sel, vece;
> >       uint64_t value;
> > +    if (!check_vldi_mode(a)) {
> > +        generate_exception(ctx, EXCCODE_INE);
> > +        return true;
> > +    }
> > +
> >       if (!check_vec(ctx, oprsz)) {
> >           return true;
> >       }