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.?
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.
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