linux-kernel - [PATCH] x86/rapl: Do not load in a guest

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Date:	Thu,  3 Dec 2015 19:27:02 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	Arnaldo Carvalho de Melo <acme@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
	Jacob Pan <jacob.jun.pan@...ux.intel.com>,
	Peter Zijlstra <peterz@...radead.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH] x86/rapl: Do not load in a guest

From: Borislav Petkov <bp@...e.de>

qemu/kvm doesn't support RAPL and RAPL doesn't have a CPUID feature bit
so check whether we're in a guest instead.

Reported-by: Hannes Reinecke <hare@...e.de>
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/kernel/cpu/perf_event_intel_rapl.c | 3 +++
 drivers/powercap/intel_rapl.c               | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
index ed446bdcbf31..bc60bc1118b4 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
@@ -711,6 +711,9 @@ static int __init rapl_pmu_init(void)
 	struct x86_pmu_quirk *quirk;
 	int i;
 
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+		return 0;
+
 	/*
 	 * check for Intel processor family 6
 	 */
diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
index cc97f0869791..297a9b5074e2 100644
--- a/drivers/powercap/intel_rapl.c
+++ b/drivers/powercap/intel_rapl.c
@@ -1511,6 +1511,9 @@ static int __init rapl_init(void)
 	int ret = 0;
 	const struct x86_cpu_id *id;
 
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+		return -ENODEV;
+
 	id = x86_match_cpu(rapl_ids);
 	if (!id) {
 		pr_err("driver does not support CPU family %d model %d\n",
-- 
2.3.5

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