From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>,
Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
tonyj@suse.com, nelson.dsouza@intel.com
Subject: Re: [PATCH 1/8] perf/x86/intel: Fix memory corruption
Date: Thu, 21 Mar 2019 17:45:41 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.21.1903211741120.1784@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190321123849.GN6521@hirez.programming.kicks-ass.net>
On Thu, 21 Mar 2019, Peter Zijlstra wrote:
> Subject: perf/x86/intel: Initialize TFA MSR
>
> Stephane reported that we don't initialize the TFA MSR, which could lead
> to trouble if the RESET value is not 0 or on kexec.
That sentence doesn't parse.
Stephane reported that the TFA MSR is not initialized by the kernel, but
the TFA bit could set by firmware or as a leftover from a kexec, which
makes the state inconsistent.
> Reported-by: Stephane Eranian <eranian@google.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> arch/x86/events/intel/core.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> index 8baa441d8000..2d3caf2d1384 100644
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c
> @@ -3575,6 +3575,12 @@ static void intel_pmu_cpu_starting(int cpu)
>
> cpuc->lbr_sel = NULL;
>
> + if (x86_pmu.flags & PMU_FL_TFA) {
> + WARN_ON_ONCE(cpuc->tfa_shadow);
Hmm. I wouldn't warn here as this is a legit state for kexec/kdump and I
don't think we can figure out whether this comes directly from the
firmware.
Thanks,
tglx
next prev parent reply other threads:[~2019-03-21 16:45 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-14 13:01 [RFC][PATCH 0/8] perf/x86: event scheduling cleanups Peter Zijlstra
2019-03-14 13:01 ` [PATCH 1/8] perf/x86/intel: Fix memory corruption Peter Zijlstra
2019-03-15 11:29 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2019-03-19 6:29 ` [PATCH 1/8] " Stephane Eranian
2019-03-19 11:05 ` Peter Zijlstra
2019-03-19 17:52 ` Stephane Eranian
2019-03-19 18:20 ` Peter Zijlstra
2019-03-20 20:47 ` Stephane Eranian
2019-03-20 20:52 ` Stephane Eranian
2019-03-20 22:22 ` Peter Zijlstra
2019-03-21 12:38 ` Peter Zijlstra
2019-03-21 16:45 ` Thomas Gleixner [this message]
2019-03-21 17:10 ` Peter Zijlstra
2019-03-21 17:17 ` Thomas Gleixner
2019-03-21 18:20 ` Peter Zijlstra
2019-03-21 19:42 ` Tony Jones
2019-03-21 19:47 ` DSouza, Nelson
2019-03-21 20:07 ` Peter Zijlstra
2019-03-21 23:16 ` DSouza, Nelson
2019-03-22 22:14 ` DSouza, Nelson
2019-03-21 17:23 ` Stephane Eranian
2019-03-21 17:51 ` Thomas Gleixner
2019-03-22 19:04 ` Stephane Eranian
2019-04-03 7:32 ` Peter Zijlstra
2019-04-03 10:40 ` [tip:perf/urgent] perf/x86/intel: Initialize TFA MSR tip-bot for Peter Zijlstra
2019-04-03 11:30 ` Thomas Gleixner
2019-04-03 12:23 ` Vince Weaver
2019-03-14 13:01 ` [RFC][PATCH 2/8] perf/x86/intel: Simplify intel_tfa_commit_scheduling() Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 3/8] perf/x86: Simplify x86_pmu.get_constraints() interface Peter Zijlstra
2019-03-19 21:21 ` Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 4/8] perf/x86: Remove PERF_X86_EVENT_COMMITTED Peter Zijlstra
2019-03-19 20:48 ` Stephane Eranian
2019-03-19 21:00 ` Peter Zijlstra
2019-03-20 13:14 ` Peter Zijlstra
2019-03-20 12:23 ` Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 5/8] perf/x86/intel: Optimize intel_get_excl_constraints() Peter Zijlstra
2019-03-19 23:43 ` Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 6/8] perf/x86: Clear ->event_constraint[] on put Peter Zijlstra
2019-03-19 21:50 ` Stephane Eranian
2019-03-20 12:25 ` Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 7/8] perf/x86: Optimize x86_schedule_events() Peter Zijlstra
2019-03-19 23:55 ` Stephane Eranian
2019-03-20 13:11 ` Peter Zijlstra
2019-03-20 19:30 ` Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 8/8] perf/x86: Add sanity checks to x86_schedule_events() Peter Zijlstra
2019-03-15 7:15 ` [RFC][PATCH 0/8] perf/x86: event scheduling cleanups Stephane Eranian
2019-03-15 7:15 ` Stephane Eranian
2019-03-15 8:01 ` Peter Zijlstra
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