From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@linaro.org>
Subject: Re: Question about SMP support for ARM
Date: Mon, 12 Aug 2013 13:40:57 +0100
Message-ID: <5208D7D9.3070705@linaro.org>
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To: Chen Baozi <baozich@gmail.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>, Xen Developer List <xen-devel@lists.xen.org>
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On 08/12/2013 01:28 PM, Chen Baozi wrote:
> On Mon, Aug 12, 2013 at 01:24:40PM +0100, Julien Grall wrote:
>> On 08/12/2013 01:14 PM, Chen Baozi wrote:
>>> Hi Ian & Julien,
>>
>> Hi,
>>
>>> It seems that Xen for ARM is not support SMP boot by default since "max_phys_cpus" is not set?
>>
>> max_phys_cpus allows use to restrict the number of cpus handled by Xen.
>> It's only used to set NR_CPUS. If the former is not set, Xen will use
>> 128 as default value (see include/asm-arm/config.h).
> 
> Thanks.
> 
> Then I think I need to find out why the log says:
> 
> Waiting for 0 other CPUs to be ready
> ...
> Brought up 1 CPUs
> 
> since I do have got 2 cores on OMAP5 and added "kick cpu" codes to
> mode_switch.S next.

Xen uses the device tree to know the real number of cpus.

You should have a node cpus similar to :

cpus {
   cpu@0 {
     device_type = "cpu";
     reg = "0";
   };
   cpu@1 {
     device_type = "cpu";
     reg = "1";
   };
};

Cheers,

-- 
Julien Grall