Re: [PATCH 8/9] KVM: arm64: Refine PMU defines for number of counters

Mark Rutland
2024-06-10T11:27:31Z

On Fri, Jun 07, 2024 at 02:31:33PM -0600, Rob Herring (Arm) wrote:
> There are 2 defines for the number of PMU counters:
> ARMV8_PMU_MAX_COUNTERS and ARMPMU_MAX_HWEVENTS. Both are the same
> currently, but Armv9.4/8.9 increases the number of possible counters
> from 32 to 33. With this change, the maximum number of counters will
> differ for KVM's PMU emulation which is PMUv3.4. Give KVM PMU emulation
> its own define to decouple it from the rest of the kernel's number PMU
> counters.
>
> The VHE PMU code needs to match the PMU driver, so switch it to use
> ARMPMU_MAX_HWEVENTS instead.
>
> Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
> arch/arm64/kvm/pmu-emul.c | 8 ++++----
> arch/arm64/kvm/pmu.c | 5 +++--
> include/kvm/arm_pmu.h | 3 ++-
> include/linux/perf/arm_pmuv3.h | 2 --
> 4 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
> index da5ba9d061e8..77fe79b2ba04 100644
> --- a/arch/arm64/kvm/pmu-emul.c
> +++ b/arch/arm64/kvm/pmu-emul.c
> @@ -234,7 +234,7 @@ void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu)
> int i;
> struct kvm_pmu *pmu = &vcpu->arch.pmu;
>
> - for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
> + for (i = 0; i < KVM_ARMV8_PMU_MAX_COUNTERS; i++)
> pmu->pmc[i].idx = i;
> }
>
> @@ -261,7 +261,7 @@ void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu)
> {
> int i;
>
> - for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
> + for (i = 0; i < KVM_ARMV8_PMU_MAX_COUNTERS; i++)
> kvm_pmu_release_perf_event(kvm_vcpu_idx_to_pmc(vcpu, i));
> irq_work_sync(&vcpu->arch.pmu.overflow_work);
> }
> @@ -292,7 +292,7 @@ void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
> if (!(kvm_vcpu_read_pmcr(vcpu) & ARMV8_PMU_PMCR_E) || !val)
> return;
>
> - for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
> + for (i = 0; i < KVM_ARMV8_PMU_MAX_COUNTERS; i++) {
> struct kvm_pmc *pmc;
>
> if (!(val & BIT(i)))
> @@ -324,7 +324,7 @@ void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
> if (!kvm_vcpu_has_pmu(vcpu) || !val)
> return;
>
> - for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
> + for (i = 0; i < KVM_ARMV8_PMU_MAX_COUNTERS; i++) {
> struct kvm_pmc *pmc;
>
> if (!(val & BIT(i)))
> diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
> index 01c9a9efdd1c..7eaf5f7aeae9 100644
> --- a/arch/arm64/kvm/pmu.c
> +++ b/arch/arm64/kvm/pmu.c
> @@ -5,6 +5,7 @@
> */
> #include <linux/kvm_host.h>
> #include <linux/perf_event.h>
> +#include <linux/perf/arm_pmu.h>
>
> #include <asm/arm_pmuv3.h>
>
> @@ -96,7 +97,7 @@ static void kvm_vcpu_pmu_enable_el0(unsigned long events)
> u64 typer;
> u32 counter;
>
> - for_each_set_bit(counter, &events, 32) {
> + for_each_set_bit(counter, &events, ARMPMU_MAX_HWEVENTS) {
> typer = kvm_vcpu_pmu_read_evtype_direct(counter);
> typer &= ~ARMV8_PMU_EXCLUDE_EL0;
> kvm_vcpu_pmu_write_evtype_direct(counter, typer);
> @@ -111,7 +112,7 @@ static void kvm_vcpu_pmu_disable_el0(unsigned long events)
> u64 typer;
> u32 counter;
>
> - for_each_set_bit(counter, &events, 32) {
> + for_each_set_bit(counter, &events, ARMPMU_MAX_HWEVENTS) {
> typer = kvm_vcpu_pmu_read_evtype_direct(counter);
> typer |= ARMV8_PMU_EXCLUDE_EL0;
> kvm_vcpu_pmu_write_evtype_direct(counter, typer);
> diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
> index 871067fb2616..e08aeec5d936 100644
> --- a/include/kvm/arm_pmu.h
> +++ b/include/kvm/arm_pmu.h
> @@ -10,6 +10,7 @@
> #include <linux/perf_event.h>
> #include <linux/perf/arm_pmuv3.h>
>
> +#define KVM_ARMV8_PMU_MAX_COUNTERS 32
>
> #if IS_ENABLED(CONFIG_HW_PERF_EVENTS) && IS_ENABLED(CONFIG_KVM)
> struct kvm_pmc {
> @@ -25,7 +26,7 @@ struct kvm_pmu_events {
> struct kvm_pmu {
> struct irq_work overflow_work;
> struct kvm_pmu_events events;
> - struct kvm_pmc pmc[ARMV8_PMU_MAX_COUNTERS];
> + struct kvm_pmc pmc[KVM_ARMV8_PMU_MAX_COUNTERS];
> int irq_num;
> bool created;
> bool irq_level;
> diff --git a/include/linux/perf/arm_pmuv3.h b/include/linux/perf/arm_pmuv3.h
> index caa09241ad4f..c902fe64f070 100644
> --- a/include/linux/perf/arm_pmuv3.h
> +++ b/include/linux/perf/arm_pmuv3.h
> @@ -6,8 +6,6 @@
> #ifndef __PERF_ARM_PMUV3_H
> #define __PERF_ARM_PMUV3_H
>
> -#define ARMV8_PMU_MAX_COUNTERS 32
> -
> /*
> * Common architectural and microarchitectural event numbers.
> */
>
> --
> 2.43.0