Re: [kvm-unit-tests PATCH v1 1/2] arm/pmu: skip the PMU introspection test if missing

[Zenghui Yu]

On 2024/7/3 0:35, Alex Bennée wrote:
> The test for number of events is not a substitute for properly
> checking the feature register. Fix the define and skip if PMUv3 is not
> available on the system. This includes emulator such as QEMU which
> don't implement PMU counters as a matter of policy.
>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Cc: Anders Roxell <anders.roxell@linaro.org>
> ---
>  arm/pmu.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arm/pmu.c b/arm/pmu.c
> index 9ff7a301..66163a40 100644
> --- a/arm/pmu.c
> +++ b/arm/pmu.c
> @@ -200,7 +200,7 @@ static void test_overflow_interrupt(bool 
> overflow_at_64bits) {}
>  #define ID_AA64DFR0_PERFMON_MASK  0xf
>  
>  #define ID_DFR0_PMU_NOTIMPL	0b0000
> -#define ID_DFR0_PMU_V3         0b0001
> +#define ID_DFR0_PMU_V3         0b0011

Why? This is a macro used for AArch64 and DDI0487J.a (D19.2.59, the
description of the PMUVer field) says that

"0b0001    Performance Monitors Extension, PMUv3 implemented."

while 0b0011 is a reserved value.

Thanks,
Zenghui