linux-kernel - Re: [RFC][PATCH] nmi watchdog: handle NMI_IO_APIC on nmi

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Message-ID: <20080326182333.GA11187@elte.hu>
Date:	Wed, 26 Mar 2008 19:23:33 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Aristeu Rozanski <aris@...vo.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org
Subject: Re: [RFC][PATCH] nmi watchdog: handle NMI_IO_APIC on nmi_watchdog


* Aristeu Rozanski <aris@...vo.org> wrote:

> > stop_apic_nmi_watchdog() doesnt currently properly disable the 
> > generation of NMIs when they come from an IO-APIC, so this will need 
> > more fixes i believe. One approach would be to save the IO-APIC id and 
> > pin when the watchdog is set up, and use it later on to poke that 
> > IO-APIC register to disable NMI generation there.
> the patch I sent has this change:
> 
> @@ -270,6 +270,8 @@ void stop_apic_nmi_watchdog(void *unused
>                 return;
>         if (nmi_watchdog == NMI_LOCAL_APIC)
>                 lapic_watchdog_stop();
> +       else
> +               __acpi_nmi_disable(NULL);
>         __get_cpu_var(wd_enabled) = 0;
>         atomic_dec(&nmi_active);
>  }
> 
> and:
> static void __acpi_nmi_disable(void *__unused)
> {       
>         apic_write(APIC_LVT0, APIC_DM_NMI | APIC_LVT_MASKED);
> }
> 
> do you think this isn't enough?

but this stops all NMIs, not just the IO-APIC generated ones, doesnt it? 

	Ingo
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