Re: [kvm-unit-tests PATCH v2 3/9] arm: pmu: Add a pmu struct

[Andrew Jones <drjones@redhat.com>]

On Thu, Jan 30, 2020 at 12:25:04PM +0100, Eric Auger wrote:
> This struct aims at storing information potentially used by
> all tests such as the pmu version, the read-only part of the
> PMCR, the number of implemented event counters, ...
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> ---
>  arm/pmu.c | 30 +++++++++++++++++++++++++-----
>  1 file changed, 25 insertions(+), 5 deletions(-)
> 
> diff --git a/arm/pmu.c b/arm/pmu.c
> index e5e012d..d24857e 100644
> --- a/arm/pmu.c
> +++ b/arm/pmu.c
> @@ -33,7 +33,14 @@
>  
>  #define NR_SAMPLES 10
>  
> -static unsigned int pmu_version;
> +struct pmu {
> +	unsigned int version;
> +	unsigned int nb_implemented_counters;
> +	uint32_t pmcr_ro;
> +};
> +
> +static struct pmu pmu;
> +
>  #if defined(__arm__)
>  #define ID_DFR0_PERFMON_SHIFT 24
>  #define ID_DFR0_PERFMON_MASK  0xf
> @@ -265,7 +272,7 @@ static bool check_cpi(int cpi)
>  static void pmccntr64_test(void)
>  {
>  #ifdef __arm__
> -	if (pmu_version == 0x3) {
> +	if (pmu.version == 0x3) {
>  		if (ERRATA(9e3f7a296940)) {
>  			write_sysreg(0xdead, PMCCNTR64);
>  			report(read_sysreg(PMCCNTR64) == 0xdead, "pmccntr64");
> @@ -278,9 +285,22 @@ static void pmccntr64_test(void)
>  /* Return FALSE if no PMU found, otherwise return TRUE */
>  static bool pmu_probe(void)
>  {
> -	pmu_version = get_pmu_version();
> -	report_info("PMU version: %d", pmu_version);
> -	return pmu_version != 0 && pmu_version != 0xf;
> +	uint32_t pmcr;
> +
> +	pmu.version = get_pmu_version();
> +	report_info("PMU version: %d", pmu.version);
> +
> +	if (pmu.version == 0 || pmu.version == 0xF)
> +		return false;
> +
> +	pmcr = get_pmcr();
> +	pmu.pmcr_ro = pmcr & 0xFFFFFF80;

I'd prefer we spell out what fields we consider RO. Also this mask doesn't
seem right to me. BIT[7] isn't RO, is it?

> +	pmu.nb_implemented_counters =
> +		(pmcr >> PMU_PMCR_N_SHIFT) & PMU_PMCR_N_MASK;
> +	report_info("Implements %d event counters",
> +		    pmu.nb_implemented_counters);
> +
> +	return true;
>  }
>  
>  int main(int argc, char *argv[])
> -- 
> 2.20.1
> 
> 

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