From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758006Ab3CTQRg (ORCPT ); Wed, 20 Mar 2013 12:17:36 -0400 Received: from mail-pb0-f48.google.com ([209.85.160.48]:51278 "EHLO mail-pb0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757946Ab3CTQRe (ORCPT ); Wed, 20 Mar 2013 12:17:34 -0400 From: dirk.brandewie@gmail.com To: linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org Cc: Dirk Brandewie , Dirk Brandewie Subject: [PATCH] cpufreq/intel_pstate: Add function to check that all MSR's are valid Date: Wed, 20 Mar 2013 09:17:24 -0700 Message-Id: <1363796244-6658-1-git-send-email-dirk.brandewie@gmail.com> X-Mailer: git-send-email 1.7.7.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dirk Brandewie Some VMs seem to try to implement some MSRs but not all the registers the driver needs. Check to make sure all the MSR that we need are available. If any of the required MSRs are not available refuse to load. Signed-off-by: Dirk Brandewie --- drivers/cpufreq/intel_pstate.c | 26 ++++++++++++++++++++++++++ 1 files changed, 26 insertions(+), 0 deletions(-) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index f6dd1e7..cd9c5f4 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -752,6 +752,29 @@ static struct cpufreq_driver intel_pstate_driver = { static int __initdata no_load; +static int intel_pstate_msrs_not_valid(void) +{ + /* Check that all the msr's we are using are valid. */ + u64 aperf, mperf, tmp; + + rdmsrl(MSR_IA32_APERF, aperf); + rdmsrl(MSR_IA32_MPERF, mperf); + + if (!intel_pstate_min_pstate() || + !intel_pstate_max_pstate() || + !intel_pstate_turbo_pstate()) + return -ENODEV; + + rdmsrl(MSR_IA32_APERF, tmp); + if (!(tmp - aperf)) + return -ENODEV; + + rdmsrl(MSR_IA32_MPERF, tmp); + if (!(tmp - mperf)) + return -ENODEV; + + return 0; +} static int __init intel_pstate_init(void) { int cpu, rc = 0; @@ -764,6 +787,9 @@ static int __init intel_pstate_init(void) if (!id) return -ENODEV; + if (intel_pstate_msrs_not_valid()) + return -ENODEV; + pr_info("Intel P-state driver initializing.\n"); all_cpu_data = vmalloc(sizeof(void *) * num_possible_cpus()); -- 1.7.7.6