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Re: [Xen-devel] [PATCH] xen: arm: ignore CPUs which are not marked available in the DT

Hi Ian,

On 23/07/14 19:36, Ian Campbell wrote:
On Wed, 2014-07-23 at 18:15 +0100, Julien Grall wrote:
On 07/23/2014 05:45 PM, Ian Campbell wrote:
Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
  xen/arch/arm/smpboot.c |    3 +++
  1 file changed, 3 insertions(+)

diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index cf149da..4b0a738 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -134,6 +134,9 @@ void __init smp_init_cpus(void)
          if ( !dt_device_type_is_equal(cpu, "cpu") )

+        if ( !dt_device_is_available(cpu) )
+            continue;

I can't find a such things on the Linux device tree bindings.

status is a generic property which is common to all nodes, it comes from

  Do you
have a use case where CPU are marked disabled?

I use it locally when booting with models -- it allows me to turn off
cpus in the base .dts file using a wrapper instead of having to edit the

I read the ePAPR and the property status on CPU node. AFAIU, the property doesn't have this meaning for a such node.

This property means the CPU is in quiescent state and property to bring up the CPU is provides in the device tree node.


Before starting a client program on the boot cpu, the boot program shall set certain properties in the
device tree passed to the client as follows:
• Each secondary CPU’s cpu node shall have a status property with a value of “disabled”.


Julien Grall

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