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

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Message-ID: <4AC10588.90808@linux.intel.com>
Date:	Mon, 28 Sep 2009 20:50:48 +0200
From:	Andi Kleen <ak@...ux.intel.com>
To:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
CC:	Huang Ying <ying.huang@...el.com>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.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

Hidetoshi Seto wrote:

> 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.

You can just disable the poll handler in the test suite. That's
what we did.

> 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.

Using magic numbers for this seems very hackish.

-Andi
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