[PATCH v4 07/16] KVM: arm64: PMU: Add counter_index_to_*reg() helpers

[Reiji Watanabe]

Hi Marc,

On Sun, Nov 13, 2022 at 8:38 AM Marc Zyngier <maz at kernel.org> wrote:
>
> In order to reduce the boilerplate code, add two helpers returning
> the counter register index (resp. the event register) in the vcpu
> register file from the counter index.
>
> Reviewed-by: Oliver Upton <oliver.upton at linux.dev>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  arch/arm64/kvm/pmu-emul.c | 33 ++++++++++++++++++---------------
>  1 file changed, 18 insertions(+), 15 deletions(-)
>
> diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
> index 1fab889dbc74..faab0f57a45d 100644
> --- a/arch/arm64/kvm/pmu-emul.c
> +++ b/arch/arm64/kvm/pmu-emul.c
> @@ -77,6 +77,16 @@ static struct kvm_vcpu *kvm_pmc_to_vcpu(struct kvm_pmc *pmc)
>         return container_of(vcpu_arch, struct kvm_vcpu, arch);
>  }
>
> +static u32 counter_index_to_reg(u64 idx)
> +{
> +       return (idx == ARMV8_PMU_CYCLE_IDX) ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + idx;
> +}
> +
> +static u32 counter_index_to_evtreg(u64 idx)
> +{
> +       return (idx == ARMV8_PMU_CYCLE_IDX) ? PMCCFILTR_EL0 : PMEVTYPER0_EL0 + idx;
> +}

It looks like we could use this function for access_pmu_evtyper()
in arch/arm64/kvm/sys_regs.c as well.

Thank you,
Reiji


> +
>  /**
>   * kvm_pmu_get_counter_value - get PMU counter value
>   * @vcpu: The vcpu pointer
> @@ -91,8 +101,7 @@ u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
>         if (!kvm_vcpu_has_pmu(vcpu))
>                 return 0;
>
> -       reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)
> -               ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + pmc->idx;
> +       reg = counter_index_to_reg(select_idx);
>         counter = __vcpu_sys_reg(vcpu, reg);
>
>         /*
> @@ -122,8 +131,7 @@ void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val)
>         if (!kvm_vcpu_has_pmu(vcpu))
>                 return;
>
> -       reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
> -             ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_idx;
> +       reg = counter_index_to_reg(select_idx);
>         __vcpu_sys_reg(vcpu, reg) += (s64)val - kvm_pmu_get_counter_value(vcpu, select_idx);
>
>         /* Recreate the perf event to reflect the updated sample_period */
> @@ -158,10 +166,7 @@ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
>
>         val = kvm_pmu_get_counter_value(vcpu, pmc->idx);
>
> -       if (pmc->idx == ARMV8_PMU_CYCLE_IDX)
> -               reg = PMCCNTR_EL0;
> -       else
> -               reg = PMEVCNTR0_EL0 + pmc->idx;
> +       reg = counter_index_to_reg(pmc->idx);
>
>         __vcpu_sys_reg(vcpu, reg) = val;
>
> @@ -404,16 +409,16 @@ static void kvm_pmu_counter_increment(struct kvm_vcpu *vcpu,
>                 u64 type, reg;
>
>                 /* Filter on event type */
> -               type = __vcpu_sys_reg(vcpu, PMEVTYPER0_EL0 + i);
> +               type = __vcpu_sys_reg(vcpu, counter_index_to_evtreg(i));
>                 type &= kvm_pmu_event_mask(vcpu->kvm);
>                 if (type != event)
>                         continue;
>
>                 /* Increment this counter */
> -               reg = __vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) + 1;
> +               reg = __vcpu_sys_reg(vcpu, counter_index_to_reg(i)) + 1;
>                 if (!kvm_pmu_idx_is_64bit(vcpu, i))
>                         reg = lower_32_bits(reg);
> -               __vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) = reg;
> +               __vcpu_sys_reg(vcpu, counter_index_to_reg(i)) = reg;
>
>                 /* No overflow? move on */
>                 if (kvm_pmu_idx_has_64bit_overflow(vcpu, i) ? reg : lower_32_bits(reg))
> @@ -549,8 +554,7 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
>         struct perf_event_attr attr;
>         u64 eventsel, counter, reg, data;
>
> -       reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)
> -             ? PMCCFILTR_EL0 : PMEVTYPER0_EL0 + pmc->idx;
> +       reg = counter_index_to_evtreg(select_idx);
>         data = __vcpu_sys_reg(vcpu, reg);
>
>         kvm_pmu_stop_counter(vcpu, pmc);
> @@ -632,8 +636,7 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
>         mask &= ~ARMV8_PMU_EVTYPE_EVENT;
>         mask |= kvm_pmu_event_mask(vcpu->kvm);
>
> -       reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
> -             ? PMCCFILTR_EL0 : PMEVTYPER0_EL0 + select_idx;
> +       reg = counter_index_to_evtreg(select_idx);
>
>         __vcpu_sys_reg(vcpu, reg) = data & mask;
>
> --
> 2.34.1
>