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Re: [kvm-unit-tests PATCH v2 4/9] arm: pmu: Check Required Event Support
From: |
Auger Eric |
Subject: |
Re: [kvm-unit-tests PATCH v2 4/9] arm: pmu: Check Required Event Support |
Date: |
Tue, 11 Feb 2020 19:08:59 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
Hi Peter,
On 2/11/20 4:33 PM, Peter Maydell wrote:
> On Thu, 30 Jan 2020 at 11:25, Eric Auger <address@hidden> wrote:
>>
>> If event counters are implemented check the common events
>> required by the PMUv3 are implemented.
>>
>> Some are unconditionally required (SW_INCR, CPU_CYCLES,
>> either INST_RETIRED or INST_SPEC). Some others only are
>> required if the implementation implements some other features.
>>
>> Check those wich are unconditionally required.
>>
>> This test currently fails on TCG as neither INST_RETIRED
>> or INST_SPEC are supported.
>>
>> Signed-off-by: Eric Auger <address@hidden>
>>
>> ---
>>
>
>> +static bool is_event_supported(uint32_t n, bool warn)
>> +{
>> + uint64_t pmceid0 = read_sysreg(pmceid0_el0);
>> + uint64_t pmceid1 = read_sysreg_s(PMCEID1_EL0);
>> + bool supported;
>> + uint64_t reg;
>> +
>> + /*
>> + * The low 32-bits of PMCEID0/1 respectly describe
>
> "respectively"
>
>> + * event support for events 0-31/32-63. Their High
>> + * 32-bits describe support for extended events
>> + * starting at 0x4000, using the same split.
>> + */
>> + if (n >= 0x0 && n <= 0x3F)
>> + reg = (pmceid0 & 0xFFFFFFFF) | ((pmceid1 & 0xFFFFFFFF) <<
>> 32);
>> + else if (n >= 0x4000 && n <= 0x403F)
>> + reg = (pmceid0 >> 32) | ((pmceid1 >> 32) << 32);
>> + else
>> + abort();
>> +
>> + supported = reg & (1UL << (n & 0x3F));
>> +
>> + if (!supported && warn)
>> + report_info("event %d is not supported", n);
>> + return supported;
>> +}
>> +
>> +static void test_event_introspection(void)
>> +{
>> + bool required_events;
>> +
>> + if (!pmu.nb_implemented_counters) {
>> + report_skip("No event counter, skip ...");
>> + return;
>> + }
>> +
>> + /* PMUv3 requires an implementation includes some common events */
>> + required_events = is_event_supported(0x0, true) /* SW_INCR */ &&
>> + is_event_supported(0x11, true) /* CPU_CYCLES */ &&
>> + (is_event_supported(0x8, true) /* INST_RETIRED */
>> ||
>> + is_event_supported(0x1B, true) /* INST_PREC */);
>> +
>> + if (pmu.version == 0x4) {
>
> This condition will only test for v8.1-required events if the PMU
> is exactly 8.1, so you lose coverage if the implementation happens
> to support ARMv8.4-PMU. Hopefully you have already bailed out
> for "ID_AA64DFR0_EL1.PMUVer == 0xf" which means "non-standard IMPDEF
> PMU", in which case you can just check >= 0x4.
OK thanks
Eric
>
>> + /* ARMv8.1 PMU: STALL_FRONTEND and STALL_BACKEND are
>> required */
>> + required_events = required_events &&
>> + is_event_supported(0x23, true) &&
>> + is_event_supported(0x24, true);
>> + }
>> +
>> + report(required_events, "Check required events are implemented");
>> +}
>> +
>> #endif
>
> thanks
> -- PMM
>