Re: [Qemu-devel] [RFC 07/12] target-i386/cpu: Introduce apic_id_for_cpu() function

[Igor Mammedov <imammedo@redhat.com>]

On Wed,  9 Jan 2013 16:53:47 -0200
Eduardo Habkost <ehabkost@redhat.com> wrote:

> This function will be used by both the CPU initialization code and the
> fw_cfg table initialization code.
> 
> Later this function will be updated to generate APIC IDs according to
> the CPU topology.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  target-i386/cpu.c | 17 ++++++++++++++++-
>  target-i386/cpu.h |  2 ++
>  2 files changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 492656c..33787dc 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -2192,6 +2192,21 @@ void x86_cpu_realize(Object *obj, Error **errp)
>      cpu_reset(CPU(cpu));
>  }
>  
> +/* Calculates initial APIC ID for a specific CPU index
> + *
> + * Currently we need to be able to calculate the APIC ID from the CPU index
> + * alone (without requiring a CPU object), as the QEMU<->Seabios interfaces have
> + * no concept of "CPU index", and the NUMA tables on fw_cfg need the APIC ID of
> + * all CPUs up to max_cpus.
> + */
> +uint32_t apic_id_for_cpu(unsigned int cpu_index)
> +{
> +    /* right now APIC ID == CPU index. this will eventually change to use
> +     * the CPU topology configuration properly
> +     */
> +    return cpu_index;
> +}
> +
>  static void x86_cpu_initfn(Object *obj)
>  {
>      CPUState *cs = CPU(obj);
> @@ -2226,7 +2241,7 @@ static void x86_cpu_initfn(Object *obj)
>                          x86_cpuid_get_tsc_freq,
>                          x86_cpuid_set_tsc_freq, NULL, NULL, NULL);
>  
> -    env->cpuid_apic_id = cs->cpu_index;
> +    env->cpuid_apic_id = apic_id_for_cpu(cs->cpu_index);
APIC ID is set by board so CPU shouldn't do it by itself.

Could you create static property for it and set it from board using property
instead?

>  
>      /* init various static tables used in TCG mode */
>      if (tcg_enabled() && !inited) {
> diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> index f3c9df5..dbd9899 100644
> --- a/target-i386/cpu.h
> +++ b/target-i386/cpu.h
> @@ -1238,4 +1238,6 @@ void disable_kvm_pv_eoi(void);
>  /* Return name of 32-bit register, from a R_* constant */
>  const char *get_register_name_32(unsigned int reg);
>  
> +uint32_t apic_id_for_cpu(unsigned int cpu_index);
> +
>  #endif /* CPU_I386_H */
> -- 
> 1.7.11.7
> 


-- 
Regards,
  Igor