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From: Peter Zijlstra <peterz@infradead.org>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>,
	Steven Rostedt <rostedt@goodmis.org>,
	Andy Lutomirski <luto@kernel.org>, x86-ml <x86@kernel.org>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] #MC mess
Date: Tue, 18 Feb 2020 21:02:00 +0100	[thread overview]
Message-ID: <20200218200200.GE11457@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F7F57B937@ORSMSX115.amr.corp.intel.com>

On Tue, Feb 18, 2020 at 06:20:38PM +0000, Luck, Tony wrote:
> > Anything else I'm missing? It is likely...
> 
> +	hw_breakpoint_disable();
> +	static_key_disable(&__tracepoint_read_msr.key);
> +	tracing_off();
> +
>  	ist_enter(regs);
> 
> How about some code to turn all those back on for a recoverable (where we actually recovered) #MC?

Then please rewrite the #MC entry code to deal with nested exceptions
unmasking the MCE, very similr to NMI.

The moment you allow tracing, jump_labels or anything else you can
expect #PF, #BP and probably #DB while inside #MC, those will then IRET
and re-enable the #MC.

The current situation is completely and utterly buggered.

  parent reply	other threads:[~2020-02-18 20:02 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-18 17:31 [RFC] #MC mess Borislav Petkov
2020-02-18 18:11 ` Steven Rostedt
2020-02-18 19:50   ` Borislav Petkov
2020-02-18 20:08     ` Steven Rostedt
2020-02-18 20:30       ` Peter Zijlstra
2020-02-18 20:52       ` Borislav Petkov
2020-02-18 18:20 ` Luck, Tony
2020-02-18 19:51   ` Borislav Petkov
2020-02-18 19:54     ` Luck, Tony
2020-02-18 20:00       ` Borislav Petkov
2020-02-18 20:05         ` Luck, Tony
2020-02-18 20:02   ` Peter Zijlstra [this message]
2020-02-18 20:09     ` Borislav Petkov
2020-02-18 20:11     ` Luck, Tony
2020-02-18 20:34       ` Peter Zijlstra
2020-02-18 21:49         ` Peter Zijlstra
2020-02-18 21:53           ` Peter Zijlstra
2020-02-18 22:41             ` Frederic Weisbecker
2020-02-18 22:40           ` Frederic Weisbecker
2020-02-18 23:17     ` Andy Lutomirski
2020-02-18 23:10   ` Andy Lutomirski
2020-02-18 23:17     ` Steven Rostedt
2020-02-19  0:15 ` Andy Lutomirski
2020-02-19  8:15   ` Peter Zijlstra
2020-02-19 14:21     ` Steven Rostedt
2020-02-19 14:43       ` Borislav Petkov
2020-02-19 15:05       ` Peter Zijlstra
2020-02-19 15:20         ` Andy Lutomirski

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