Re: [PATCH] xen/arm: Fix smp_send_call_function_mask() for current CPU

[Julien Grall <julien.grall@linaro.org>]

On 14/08/14 13:44, Julien Grall wrote:
> On 08/14/2014 12:47 PM, Anup Patel wrote:
>> The smp_send_call_function_mask() does not work on Foundation v8
>> model with one CPU. The reason being gicv2_send_SGI() is called
>> with irqmode==SGI_TARGET_LIST and *cpu_mask=0x1 on CPU0 which
>> does not work on Foundation v8 model.
>
> Please provide any steps, trace that make you think that irqmode ==
> SGI_TARGET_LIST and *cpu_mask=0x1 is not working on Foundation V8 Model.
>
>> Further, it is really strange that smp_send_call_function_mask()
>> depends on GIC SGIs for calling function on current CPU.
>
> Why it's strange??? The GIC specification doesn't seem to add any
> restriction about sending an SGI to the current CPU.
>
> It clearly looks like a bug in another part of Xen. And I doubt it's
> because the Foundation Model is not able to support the use case above.
>
> Without any further explanation than "It doesn't work" and "It's
> strange", I don't think this patch should be accepted in Xen.
> You need at least to point the paragraph in the spec...
>
>> This patch fixes smp_send_call_function_mask() for current CPU
>> by directly calling smp_call_function_interrupt() on current CPU.
>> This is very similar to what Xen x86 does.
>
> What was done in x86 may not make sense on ARM....
>
> For me the current code is valid... So far, I didn't see any issue on
> different boards. I've also used recently the Foundation v8 Model [1],
> without any issue.

I just saw their is new version of the model. I've tested sucessfully 
xen on:

ARM V8 Foundation Model r0p0 (model build 0.8.5206)

I will give a try on newer version.

Regards,

-- 
Julien Grall