Re: [PATCH 17/27] target/s390x: Use cpu_{ld,st}*_mmu in do_csst

[Philippe Mathieu-Daudé]

Hi Richard,

On 20/5/23 18:26, Richard Henderson wrote:
> Use cpu_ld16_mmu and cpu_st16_mmu to eliminate the special case,
> and change all of the *_data_ra functions to match.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> Cc: qemu-s390x@nongnu.org
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>   target/s390x/tcg/mem_helper.c | 65 ++++++++++++++---------------------
>   1 file changed, 26 insertions(+), 39 deletions(-)
>
> diff --git a/target/s390x/tcg/mem_helper.c b/target/s390x/tcg/mem_helper.c
> index 0e0d66b3b6..b6cf24403c 100644
> --- a/target/s390x/tcg/mem_helper.c
> +++ b/target/s390x/tcg/mem_helper.c
> @@ -1737,6 +1737,9 @@ static uint32_t do_csst(CPUS390XState *env, uint32_t r3, 
> uint64_t a1,
>                           uint64_t a2, bool parallel)
>   {
>       uint32_t mem_idx = cpu_mmu_index(env, false);
> +    MemOpIdx oi16 = make_memop_idx(MO_TE | MO_128, mem_idx);
> +    MemOpIdx oi8 = make_memop_idx(MO_TE | MO_64, mem_idx);


>               if (parallel) {
>   #ifdef CONFIG_ATOMIC64
> -                MemOpIdx oi = make_memop_idx(MO_TEUQ | MO_ALIGN, mem_idx);
> -                ov = cpu_atomic_cmpxchgq_be_mmu(env, a1, cv, nv, oi, ra);
> +                ov = cpu_atomic_cmpxchgq_be_mmu(env, a1, cv, nv, oi8, ra);

Why is it safe to remove MO_ALIGN here?

>   #else
>                   /* Note that we asserted !parallel above.  */
>                   g_assert_not_reached();
>   #endif