On Mon, Jul 06, 2015 at 10:17:39AM +0800, shannon.zhao@xxxxxxxxxx wrote:
> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>
> Since the reset value of PMXEVTYPER_EL0 is UNKNOWN, use reset_unknown
> for its reset handler. Add access handler which emulates writing and
> reading PMXEVTYPER_EL0 register. When reading PMXEVCNTR_EL0, call
> perf_event_read_value to get the count value of the perf event.
>
> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> ---
> arch/arm64/kvm/sys_regs.c | 21 ++++++++++++++++++++-
> include/kvm/arm_pmu.h | 11 +++++++++++
> virt/kvm/arm/pmu.c | 37 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 68 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index b4f8dd9..2bcf1a0 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -356,6 +356,25 @@ static bool access_pmxevtyper(struct kvm_vcpu *vcpu,
> return true;
> }
>
> +static bool access_pmxevcntr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *r)
> +{
> + unsigned long val;
> +
> + if (p->is_write) {
> + val = *vcpu_reg(vcpu, p->Rt);
> + kvm_pmu_set_counter_value(vcpu, vcpu_sys_reg(vcpu, PMSELR_EL0),
> + val & 0xffffffffUL);
> + } else {
> + val = kvm_pmu_get_counter_value(vcpu,
> + vcpu_sys_reg(vcpu, PMSELR_EL0));
> + *vcpu_reg(vcpu, p->Rt) = val;
> + }
> +
> + return true;
> +}
> +
> /* Silly macro to expand the DBG{BCR,BVR,WVR,WCR}n_EL1 registers in one go */
> #define DBG_BCR_BVR_WCR_WVR_EL1(n) \
> /* DBGBVRn_EL1 */ \
> @@ -577,7 +596,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
> access_pmxevtyper, reset_unknown, PMXEVTYPER_EL0 },
> /* PMXEVCNTR_EL0 */
> { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b010),
> - trap_raz_wi },
> + access_pmxevcntr, reset_unknown, PMXEVCNTR_EL0 },
> /* PMUSERENR_EL0 */
> { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b000),
> trap_raz_wi },
> diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
> index 1050b24..40ab4a0 100644
> --- a/include/kvm/arm_pmu.h
> +++ b/include/kvm/arm_pmu.h
> @@ -45,11 +45,22 @@ struct kvm_pmu {
>
> #ifdef CONFIG_KVM_ARM_PMU
> void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu);
> +void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, unsigned long select_idx,
> + unsigned long val);
> +unsigned long kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu,
> + unsigned long select_idx);
> void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, unsigned long data,
> unsigned long select_idx);
> void kvm_pmu_init(struct kvm_vcpu *vcpu);
> #else
> static inline void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu) {}
> +void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, unsigned long select_idx,
> + unsigned long val) {}
> +unsigned long kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu,
> + unsigned long select_idx)
> +{
> + return 0;
> +}
> void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, unsigned long data,
> unsigned long select_idx) {}
> static inline void kvm_pmu_init(struct kvm_vcpu *vcpu) {}
> diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
> index 50a3c82..361fa51 100644
> --- a/virt/kvm/arm/pmu.c
> +++ b/virt/kvm/arm/pmu.c
> @@ -97,6 +97,43 @@ void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
> }
>
> /**
> + * kvm_pmu_set_counter_value - set PMU counter value
> + * @vcpu: The vcpu pointer
> + * @select_idx: The counter index
> + * @val: the value to be set
> + */
> +void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, unsigned long select_idx,
> + unsigned long val)
> +{
> + struct kvm_pmu *pmu = &vcpu->arch.pmu;
> + struct kvm_pmc *pmc = &pmu->pmc[select_idx];
> +
> + pmc->counter = val;
how does this help generate an overflow event when expected?
> +}
> +
> +/**
> + * kvm_pmu_set_counter_value - set PMU counter value
s/set/get/
> + * @vcpu: The vcpu pointer
> + * @select_idx: The counter index
> + *
> + * Call perf_event API to get the event count
> + */
> +unsigned long kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu,
> + unsigned long select_idx)
> +{
> + u64 enabled, running;
> + struct kvm_pmu *pmu = &vcpu->arch.pmu;
> + struct kvm_pmc *pmc = &pmu->pmc[select_idx];
> + unsigned long counter = pmc->counter;
> +
> + if (pmc->perf_event) {
> + counter += perf_event_read_value(pmc->perf_event,
> + &enabled, &running);
I don't quite understand the summation here or feel convinced that
enabled and running should be simply thrown away.
Can you explain this, potentially in the kdocs above...
> + }
> + return counter;
> +}
> +
> +/**
> * kvm_pmu_find_hw_event - find hardware event
> * @pmu: The pmu pointer
> * @event_select: The number of selected event type
> --
> 2.1.0
>
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