From: Horms <horms@verge.net.au>
Subject: Re: [PATCH] kexec: framework and i386 (Take XIV)
Date: Fri, 1 Sep 2006 11:56:11 +0900
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To: Akio Takebe <takebe_akio@jp.fujitsu.com>
Cc: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>, Kazuo Moriwaka <moriwaka@valinux.co.jp>, xen-devel@lists.xensource.com, "Zou, Nanhai" <nanhai.zou@intel.com>, Magnus Damm <magnus@valinux.co.jp>, Isaku Yamahata <yamahata@valinux.co.jp>, Mark Williamson <mark.williamson@cl.cam.ac.uk>, xen-ia64-devel@lists.xensource.com
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On Thu, Aug 31, 2006 at 05:55:52PM +0900, Akio Takebe wrote:
> Hi, Horms and Magnus
> 
> Good work. :-)
> I have one commet.
> 
> I believe crash_kexec should be directly called 
> when unknown NMI is occurred.
> In your patch, crash_kexec is called as the bellow.
>   1. unknown NMI is occurred. (e.g. by pushing NMI botton)
>   2. xen recieved NMI and call do_nmi.
>   3. xen report to dom0 by using raise_softirq(NMI_SOFTIRQ).
>   4. dom0 call crash_kexec of dom0.
>   5. crash_kexec of dom0 call crash_kexec of xen
> 
> Am I correct?
> The above process is not reliable if I'm correct.
> So I belive crash_kexec of xen should be directly called like the 
> following patch.
> 
> diff -r 9611a5c9e1a1 xen/arch/x86/traps.c
> --- a/xen/arch/x86/traps.c      Thu Aug 31 13:12:26 2006 +0900
> +++ b/xen/arch/x86/traps.c      Thu Aug 31 17:40:19 2006 +0900
> @@ -1612,6 +1612,7 @@ asmlinkage void do_nmi(struct cpu_user_r
>          else if ( reason & 0x40 )
>              io_check_error(regs);
>          else if ( !nmi_watchdog )
> +            crash_kexec(NULL);
>              unknown_nmi_error((unsigned char)(reason&0xff));
>      }
>  }
> 
> What do you think about it?

That seems like a good idea to me. Though I think you are missing { }.
Can you test to see if this works?

--- a/xen/arch/x86/traps.c	2006-09-01 11:53:44.000000000 +0900
+++ b/xen/arch/x86/traps.c	2006-09-01 11:53:56.000000000 +0900
@@ -1611,8 +1611,10 @@
             mem_parity_error(regs);
         else if ( reason & 0x40 )
             io_check_error(regs);
-        else if ( !nmi_watchdog )
+        else if ( !nmi_watchdog ) {
+	    crash_kexec(NULL);
             unknown_nmi_error((unsigned char)(reason&0xff));
+	}
     }
 }