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From:   Andy Lutomirski <luto@amacapital.net>
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Subject: Re: [RFC] #MC mess
Date:   Tue, 18 Feb 2020 15:10:17 -0800
Message-Id: <3CF4895A-5BCF-4E5C-B8D9-F9019DD02A12@amacapital.net>
References: <3908561D78D1C84285E8C5FCA982C28F7F57B937@ORSMSX115.amr.corp.intel.com>
Cc:     Borislav Petkov <bp@alien8.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Andy Lutomirski <luto@kernel.org>, x86-ml <x86@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>
In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F7F57B937@ORSMSX115.amr.corp.intel.com>
To:     "Luck, Tony" <tony.luck@intel.com>
Sender: linux-kernel-owner@vger.kernel.org
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> On Feb 18, 2020, at 10:20 AM, Luck, Tony <tony.luck@intel.com> wrote:
>=20
> =EF=BB=BF
>>=20
>> Anything else I'm missing? It is likely...
>=20
> +    hw_breakpoint_disable();
> +    static_key_disable(&__tracepoint_read_msr.key);
> +    tracing_off();
> +
>    ist_enter(regs);
>=20
> How about some code to turn all those back on for a recoverable (where we a=
ctually recovered) #MC?
>=20
>=20


At the very least, in the user_mode(regs) case, tracing is fine.=