Re: [PATCH v5 12/20] x86: perf: intel_pt: Intel PT PMU driver

[Alexander Shishkin]

Peter Zijlstra <peterz@xxxxxxxxxxxxx> writes:

> On Mon, Oct 13, 2014 at 04:45:40PM +0300, Alexander Shishkin wrote:
>> +static bool pt_event_valid(struct perf_event *event)
>> +{
>> +	u64 config = event->attr.config;
>> +
>> +	/* admin can set any packet generation parameters */
>> +	if (capable(CAP_SYS_ADMIN) && (config & PT_BYPASS_MASK) == config)
>> +		return true;
>> +
>> +	if ((config & PT_CONFIG_MASK) != config)
>> +		return false;
>> +
>> +	return true;
>> +}
>
> This seems to suggest PT is available to !priv users, is this right?

Yes, that's the intention. PT does CPL-based filtering in hardware and
unlike previous attempts at branch tracing, does not leak out-of-context
addresses (or any other information for that matter).

Regards,
--
Alex
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