Messages in this thread | | | Date | Wed, 6 Dec 2017 16:11:50 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH] perf: qcom_l2_pmu: don't allow guest access |
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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 <nleeder@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?
Thanks, Mark.
> > 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. >
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