Re: [PATCH v2 01/14] target/arm/cpu: Simplify checking A64_MTE bit in FEATURE_ID register

[Richard Henderson]

On 1/10/24 05:09, Philippe Mathieu-Daudé wrote:
> cpu_isar_feature(aa64_mte, cpu) is testing a AArch64-only ID
> register. The ARM_FEATURE_AARCH64 check is redundant.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>   target/arm/cpu.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> index 1c8b787482..c828b333c9 100644
> --- a/target/arm/cpu.c
> +++ b/target/arm/cpu.c
> @@ -1690,8 +1690,7 @@ void arm_cpu_post_init(Object *obj)
>       }
>   
>   #ifndef CONFIG_USER_ONLY
> -    if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64) &&
> -        cpu_isar_feature(aa64_mte, cpu)) {
> +    if (cpu_isar_feature(aa64_mte, cpu)) {
>           object_property_add_link(obj, "tag-memory",
>                                    TYPE_MEMORY_REGION,
>                                    (Object **)&cpu->tag_memory,

It is not redundant.

If !AARCH64, then the isar registers tested by aa64_mte are invalid.


r~