linux-kernel - Re: [PATCH 3/5] mce-inject: make injected mce valid only during faked handler call

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Date:	Mon, 28 Sep 2009 15:27:03 +0800
From:	Huang Ying <ying.huang@...el.com>
To:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
Cc:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Andi Kleen <ak@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/5] mce-inject: make injected mce valid only during
 faked handler call

On Mon, 2009-09-28 at 14:52 +0800, Hidetoshi Seto wrote: 
> In the current implementation, injected MCE is valid from the point
> the MCE is injected to the point the MCE is processed by the faked
> handler call.
> 
> This has an undesired side-effect: it is possible for it to be
> consumed by real machine_check_poll. This may confuse a real system
> error and may confuse the mce test suite.
> 
> To fix this, this patch changes mce_rdmsrl/wemsrl() to refer injected
> data only when injectm.valid states 3rd state "2", which indicates that
> the injected MCE entry is valid and ready for the handler.
> 
> The injectm.valid becomes "2" only during faked MCE handler call
> and protected by IRQ disabling. This make it impossible for real
> machine_check_poll to consume it.

Anyway, I don't think it is a good idea to use a magic number like "2"
here. A meaningful name is better.

And I think my original method is clearer. Because injection related
flags go inject_flags, not be mixed with normal path flag "finished".

Best Regards,
Huang Ying

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