From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757443Ab3CTSgZ (ORCPT ); Wed, 20 Mar 2013 14:36:25 -0400 Received: from mail-pb0-f44.google.com ([209.85.160.44]:47718 "EHLO mail-pb0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751873Ab3CTSgY (ORCPT ); Wed, 20 Mar 2013 14:36:24 -0400 Message-ID: <5149FFE1.7030706@gmail.com> Date: Wed, 20 Mar 2013 11:28:49 -0700 From: Dirk Brandewie User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: "Rafael J. Wysocki" CC: dirk.brandewie@gmail.com, linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org, Dirk Brandewie Subject: Re: [PATCH] cpufreq/intel_pstate: Add function to check that all MSR's are valid References: <1363796244-6658-1-git-send-email-dirk.brandewie@gmail.com> <5818534.Fj7AtdhPq1@vostro.rjw.lan> In-Reply-To: <5818534.Fj7AtdhPq1@vostro.rjw.lan> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/20/2013 11:28 AM, Rafael J. Wysocki wrote: > On Wednesday, March 20, 2013 09:17:24 AM dirk.brandewie@gmail.com wrote: >> 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 > > Is this needed for v3.9? Any pointers to bug reports etc.? > Sorry I saw right after I sent the mail that the bug report was missing https://bugzilla.redhat.com/show_bug.cgi?id=922923 Reported-by: Josh Stone Would you like me to spin the patch? > Rafael > > >> --- >> 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()); >>