Messages in this thread | | | Date | Wed, 20 Mar 2013 11:28:49 -0700 | From | Dirk Brandewie <> | Subject | Re: [PATCH] cpufreq/intel_pstate: Add function to check that all MSR's are valid |
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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 <dirk.brandewie@gmail.com> >> >> 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 <dirk.j.brandewie@intel.com> > > 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 <jistone@redhat.com>
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()); >>
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