Re: [REPOST PATCH 07/16] selftests: KVM: aarch64: Add PMU cycle counter helpers

Reiji Watanabe
2023-03-03T03:06:55Z

Hi Raghu,

On Tue, Feb 14, 2023 at 5:07 PM Raghavendra Rao Ananta
<rananta@google.com> wrote:
>
> Add basic helpers for the test to access the cycle counter
> registers. The helpers will be used in the upcoming patches
> to run the tests related to cycle counter.
>
> No functional change intended.
>
> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
> ---
> .../testing/selftests/kvm/aarch64/vpmu_test.c | 40 +++++++++++++++++++
> 1 file changed, 40 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/aarch64/vpmu_test.c b/tools/testing/selftests/kvm/aarch64/vpmu_test.c
> index d72c3c9b9c39f..15aebc7d7dc94 100644
> --- a/tools/testing/selftests/kvm/aarch64/vpmu_test.c
> +++ b/tools/testing/selftests/kvm/aarch64/vpmu_test.c
> @@ -147,6 +147,46 @@ static inline void disable_counter(int idx)
> isb();
> }
>
> +static inline uint64_t read_cycle_counter(void)
> +{
> + return read_sysreg(pmccntr_el0);
> +}
> +
> +static inline void reset_cycle_counter(void)
> +{
> + uint64_t v = read_sysreg(pmcr_el0);
> +
> + write_sysreg(ARMV8_PMU_PMCR_C | v, pmcr_el0);
> + isb();
> +}
> +
> +static inline void enable_cycle_counter(void)
> +{
> + uint64_t v = read_sysreg(pmcntenset_el0);
> +
> + write_sysreg(ARMV8_PMU_CNTENSET_C | v, pmcntenset_el0);
> + isb();
> +}

You might want to use enable_counter() and disable_counter()
from enable_cycle_counter() and disable_cycle_counter() respectively?

Thank you,
Reiji

> +
> +static inline void disable_cycle_counter(void)
> +{
> + uint64_t v = read_sysreg(pmcntenset_el0);
> +
> + write_sysreg(ARMV8_PMU_CNTENSET_C | v, pmcntenclr_el0);
> + isb();
> +}
> +
> +static inline void write_pmccfiltr(unsigned long val)
> +{
> + write_sysreg(val, pmccfiltr_el0);
> + isb();
> +}
> +
> +static inline uint64_t read_pmccfiltr(void)
> +{
> + return read_sysreg(pmccfiltr_el0);
> +}
> +
> static inline uint64_t get_pmcr_n(void)
> {
> return FIELD_GET(ARMV8_PMU_PMCR_N, read_sysreg(pmcr_el0));
> --
> 2.39.1.581.gbfd45094c4-goog
>