Re: [PATCH qemu v2] s390x: sck: load into a temporary not into in1

[Janosch Frank]

On 1/26/22 09:42, Nico Boehr wrote:
> We previously loaded into in1, but in1 is not filled during
> disassembly and hence always zero. This leads to an assertion failure:
>
>    qemu-system-s390x: /home/nrb/qemu/include/tcg/tcg.h:654: temp_idx:
>    Assertion `n >= 0 && n < tcg_ctx->nb_temps' failed.`
>
> Instead, use in2_la2_m64a to load from storage into in2 and pass that to
> the helper, which matches what we already do for SCKC.
>
> This fixes the SCK test I sent here under TCG:
> <https://www.spinics.net/lists/kvm/msg265169.html>
>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>

@David: Was this already broken when it was implemented?
I.e. do we want a "Fixes: 9dc67537 ("s390x/tcg: implement SET CLOCK ")" tag?


> ---
>   target/s390x/tcg/insn-data.def | 2 +-
>   target/s390x/tcg/translate.c   | 3 +--
>   2 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/target/s390x/tcg/insn-data.def b/target/s390x/tcg/insn-data.def
> index 3e5594210c88..848a9c9e622f 100644
> --- a/target/s390x/tcg/insn-data.def
> +++ b/target/s390x/tcg/insn-data.def
> @@ -1317,7 +1317,7 @@
>   /* SET ADDRESS SPACE CONTROL FAST */
>       F(0xb279, SACF,    S,     Z,   0, a2, 0, 0, sacf, 0, IF_PRIV)
>   /* SET CLOCK */
> -    F(0xb204, SCK,     S,     Z,   la2, 0, 0, 0, sck, 0, IF_PRIV | IF_IO)
> +    F(0xb204, SCK,     S,     Z,   0, m2_64a, 0, 0, sck, 0, IF_PRIV | IF_IO)
>   /* SET CLOCK COMPARATOR */
>       F(0xb206, SCKC,    S,     Z,   0, m2_64a, 0, 0, sckc, 0, IF_PRIV | IF_IO)
>   /* SET CLOCK PROGRAMMABLE FIELD */
> diff --git a/target/s390x/tcg/translate.c b/target/s390x/tcg/translate.c
> index dcc249a197ce..7fb87cd9f3b7 100644
> --- a/target/s390x/tcg/translate.c
> +++ b/target/s390x/tcg/translate.c
> @@ -4295,8 +4295,7 @@ static DisasJumpType op_stcke(DisasContext *s, DisasOps 
> *o)
>   #ifndef CONFIG_USER_ONLY
>   static DisasJumpType op_sck(DisasContext *s, DisasOps *o)
>   {
> -    tcg_gen_qemu_ld_i64(o->in1, o->addr1, get_mem_index(s), MO_TEQ | MO_ALIGN);
> -    gen_helper_sck(cc_op, cpu_env, o->in1);
> +    gen_helper_sck(cc_op, cpu_env, o->in2);
>       set_cc_static(s);
>       return DISAS_NEXT;
>   }