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

[Laszlo Ersek]

On 03/13/14 01:12, Eduardo Habkost wrote:
> On Wed, Mar 12, 2014 at 10:18:56PM +0100, Laszlo Ersek wrote:
>> On 03/12/14 22:17, Laszlo Ersek wrote:
>>> 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 <address@hidden>
>>>> ---
>>>>  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.
>>
>>
>> (Or vice versa -- get the limit from PROC_LEN by multiplication.)
> 
> I tried it, but the ASL compiler doesn't seem to be able to evaluate the
> expression.

Ah right, I did see Igor's comment in the file! OK then.

Thanks,
Laszlo