On 12/6/2017 11:11 AM, Mark Rutland wrote:
> On Wed, Dec 06, 2017 at 10:55:33AM -0500, Neil Leeder wrote:
>> Guests cannot access IMPDEF system registers, which are used
>> by this driver. Disable the driver if it's running in a guest VM.
>>
>> Signed-off-by: Neil Leeder <nlee...@codeaurora.org>
>> ---
>> drivers/perf/qcom_l2_pmu.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>
> Hi Neil,
>
> I'm a little confused by this. Why is this hypervisor providing a
> QCOM8130 device to the guest that it cannot use?
>
> Could you elaborate on what's going on?
>
Hi Mark,
While there's an argument that the guest shouldn't be loading the driver
in the first place, we can't control everyone's guest configuration or what
their hypervisor does.
>>
>> diff --git a/drivers/perf/qcom_l2_pmu.c b/drivers/perf/qcom_l2_pmu.c
>> index 4fdc848..49dc954 100644
>> --- a/drivers/perf/qcom_l2_pmu.c
>> +++ b/drivers/perf/qcom_l2_pmu.c
>> @@ -1057,6 +1057,10 @@ static int __init register_l2_cache_pmu_driver(void)
>> {
>> int err;
>>
>> + /* Don't enable driver if running as guest */
>> + if (!is_hyp_mode_available())
>> + return 0;
>> +
>> err = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
>> "AP_PERF_ARM_QCOM_L2_ONLINE",
>> l2cache_pmu_online_cpu,
>> --
>> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
>> Technologies Inc.
>> Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
>> a Linux Foundation Collaborative Project.
>>
Neil
--
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies
Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.
