Re: [Qemu-devel] [PATCH v2 1/4] acpi: Add ACPI_CPU_HOTPLUG_ID_LIMIT macro

[Laszlo Ersek <lersek@redhat.com>]

On 03/12/14 19:28, Eduardo Habkost wrote:
> The new macro will be helpful to allow us to detect too large SMP limits
> before it is too late.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  include/hw/acpi/cpu_hotplug_defs.h | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/include/hw/acpi/cpu_hotplug_defs.h b/include/hw/acpi/cpu_hotplug_defs.h
> index 2725b50..9f33663 100644
> --- a/include/hw/acpi/cpu_hotplug_defs.h
> +++ b/include/hw/acpi/cpu_hotplug_defs.h
> @@ -17,7 +17,15 @@
>   * between C and ASL code.
>   */
>  #define ACPI_CPU_HOTPLUG_STATUS 4
> +
> +/* Limit for CPU arch IDs for CPU hotplug. All hotpluggable CPUs should
> + * have CPUClass.get_arch_id() < ACPI_CPU_HOTPLUG_ID_LIMIT.
> + */
> +#define ACPI_CPU_HOTPLUG_ID_LIMIT 256
> +
> +/* 256 CPU IDs, 8 bits per entry: */
>  #define ACPI_GPE_PROC_LEN 32
> +
>  #define ICH9_CPU_HOTPLUG_IO_BASE 0x0CD8
>  #define PIIX4_CPU_HOTPLUG_IO_BASE 0xaf00
>  
> 

You could actually derive ACPI_GPE_PROC_LEN from
ACPI_CPU_HOTPLUG_ID_LIMIT, by dividing with CHAR_BIT. Not too important
because the two macros are adjacent and the comment explains.

Reviewed-by: Laszlo Ersek <lersek@redhat.com>