Re: [Xen-devel] [PATCH] xen/arm: disable cpuidle when linux isrunning as dom0

From: Julien Grall
Date: Thu Jul 18 2013 - 13:21:30 EST


On 17 July 2013 14:28, Stefano Stabellini
<stefano.stabellini@xxxxxxxxxxxxx> wrote:
> On Mon, 15 Jul 2013, Konrad Rzeszutek Wilk wrote:
>> On Mon, Jul 15, 2013 at 03:21:41PM +0100, Julien Grall wrote:
>> > When linux is running as dom0, Xen doesn't show the physical cpu but a
>> > virtual CPU.
>> > On some ARM SOC (for instance the exynos 5250), linux registers callbacks
>> > for cpuidle. When these callbacks are called, they will modify
>> > directly the physical cpu not the virtual one.
>> It can impact the whole board
>> > instead of dom0.
>
> Certainly this is something that should be fixed at the hypervisor level
> too. However I agree that Linux should try to avoid doing that when
> running on Xen.
>
>
>
>> Should you also call disable_cpufreq() ?
>
> Sounds like a good idea.
> Julien, could you add that to this patch?

I have checked with both the Arndale and Versatile Express without any issue.
I will resend this patch with disable_cpufreq().

--
Julien Grall
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