Re: [Xen-devel] [PATCH v5 1/6] xen: Add convenient macro boot_cpu

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Ian,

On 05/08/2014 10:57 AM, Ian Campbell wrote:
> On Tue, 2014-05-06 at 16:54 +0100, Julien Grall wrote:
>> Hi Andrew,
>>
>> On 05/02/2014 04:57 PM, Andrew Cooper wrote:
>>> On 02/05/14 16:52, Julien Grall wrote:
>>>> The macro boot_cpu will be used to get CPU variable from the boot CPU.
>>>>
>>>> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
>>>> Suggested-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
>>>> Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
>>>> Cc: Jan Beulich <jbeulich@xxxxxxxx>
>>>> Cc: Keir Fraser <keir@xxxxxxx>
>>>> ---
>>>>  xen/include/xen/percpu.h |    3 +++
>>>>  1 file changed, 3 insertions(+)
>>>>
>>>> diff --git a/xen/include/xen/percpu.h b/xen/include/xen/percpu.h
>>>> index abe0b11..0e848bf 100644
>>>> --- a/xen/include/xen/percpu.h
>>>> +++ b/xen/include/xen/percpu.h
>>>> @@ -16,6 +16,9 @@
>>>>  /* Preferred on Xen. Also see arch-defined per_cpu(). */
>>>>  #define this_cpu(var)    __get_cpu_var(var)
>>>>  
>>>> +/* Access variable on boot CPU */
>>>> +#define boot_cpu(var)   per_cpu(var, 0)
>>>> +
>>>
>>> What is this actually used for?
>>
>> I use it to retrieve PPIs (per-processor interrupt) type and initialize
>> PPIs for the new CPUs.
> 
> I wonder if perhaps this shouldn't be saved in a per-cpu variable then?

As talked on patch #2, I will drop this patch and use a static variable
to store PPIs type.

Regards,

-- 
Julien Grall

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