Re: [Qemu-devel] [PATCH v4] Use Aff1 with mpidr

[Peter Maydell <peter.maydell@linaro.org>]

On 8 June 2015 at 13:28, Pavel Fedin <p.fedin@samsung.com> wrote:
> +extern int arm_cpus_per_cluster;
> +
>  #define TYPE_AARCH64_CPU "aarch64-cpu"
>  #define AARCH64_CPU_CLASS(klass) \
>      OBJECT_CLASS_CHECK(AArch64CPUClass, (klass), TYPE_AARCH64_CPU)
> diff --git a/target-arm/cpu.c b/target-arm/cpu.c
> index 4a888ab..fa9f1c0 100644
> --- a/target-arm/cpu.c
> +++ b/target-arm/cpu.c
> @@ -383,17 +383,29 @@ static inline void unset_feature(CPUARMState *env, int feature)
>      env->features &= ~(1ULL << feature);
>  }
>
> +int arm_cpus_per_cluster = 8;

This doesn't need to be global, it doesn't need to be exposed in
a header file, and it definitely doesn't need to be non-constant.
I suggest
#define ARM_CPUS_PER_CLUSTER 8

> +
>  static void arm_cpu_initfn(Object *obj)
>  {
>      CPUState *cs = CPU(obj);
>      ARMCPU *cpu = ARM_CPU(obj);
>      static bool inited;
> +    uint32_t Aff1, Aff0;
>
>      cs->env_ptr = &cpu->env;
>      cpu_exec_init(&cpu->env);
>      cpu->cp_regs = g_hash_table_new_full(g_int_hash, g_int_equal,
>                                           g_free, g_free);
>
> +    /*
> +     * We don't support setting cluster ID ([16..23]) (known as Aff2
> +     * in later ARM ARM versions), or any of the higher affinity level fields,
> +     * so these bits always RAZ.
> +     */
> +    Aff1 = cs->cpu_index / arm_cpus_per_cluster;
> +    Aff0 = cs->cpu_index % arm_cpus_per_cluster;
> +    cpu->mp_affinity = (Aff1 << 8) | Aff0;

Worth also mentioning in the comment that KVM will override this.

These are minor nits so I plan to just fix them as I apply
this to target-arm.next, unless you object.

thanks
-- PMM