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

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Date: Mon, 10 Jun 2024 12:27:07 +0100
From: Mark Rutland <mark.rutland@....com>
To: "Rob Herring (Arm)" <robh@...nel.org>
Cc: Russell King <linux@...linux.org.uk>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>,
	Oliver Upton <oliver.upton@...ux.dev>,
	James Morse <james.morse@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	Catalin Marinas <catalin.marinas@....com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-perf-users@...r.kernel.org, kvmarm@...ts.linux.dev
Subject: Re: [PATCH 8/9] KVM: arm64: Refine PMU defines for number of counters

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@...nel.org>

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