On Wednesday, March 20, 2013 11:28:49 AM Dirk Brandewie wrote: > On 03/20/2013 11:28 AM, Rafael J. Wysocki wrote: > > On Wednesday, March 20, 2013 09:17:24 AM dirk.brandewie@xxxxxxxxx wrote: > >> From: Dirk Brandewie <dirk.brandewie@xxxxxxxxx> > >> > >> 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@xxxxxxxxx> > > > > 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@xxxxxxxxxx> > > Would you like me to spin the patch? No, thanks, this information is sufficient. Thanks, 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()); > >> > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
