linux-kernel - Re: [PATCH 5/9] KVM: arm64: pmu: Use arm

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Date: Mon, 10 Jun 2024 12:02:21 +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 5/9] KVM: arm64: pmu: Use arm_pmuv3.h register accessors

On Fri, Jun 07, 2024 at 02:31:30PM -0600, Rob Herring (Arm) wrote:
> Commit df29ddf4f04b ("arm64: perf: Abstract system register accesses
> away") split off PMU register accessor functions to a standalone header.
> Let's use it for KVM PMU code and get rid one copy of the ugly switch
> macro.
> 
> Signed-off-by: Rob Herring (Arm) <robh@...nel.org>
> ---
>  arch/arm64/include/asm/arm_pmuv3.h | 13 ++++++++
>  arch/arm64/kvm/pmu.c               | 67 +++++---------------------------------
>  2 files changed, 22 insertions(+), 58 deletions(-)

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

Mark.

> 
> diff --git a/arch/arm64/include/asm/arm_pmuv3.h b/arch/arm64/include/asm/arm_pmuv3.h
> index e96ce7900fc7..1ed91334fede 100644
> --- a/arch/arm64/include/asm/arm_pmuv3.h
> +++ b/arch/arm64/include/asm/arm_pmuv3.h
> @@ -33,6 +33,14 @@ static inline void write_pmevtypern(int n, unsigned long val)
>  	PMEVN_SWITCH(n, WRITE_PMEVTYPERN);
>  }
>  
> +#define RETURN_READ_PMEVTYPERN(n) \
> +	return read_sysreg(pmevtyper##n##_el0)
> +static inline unsigned long read_pmevtypern(int n)
> +{
> +	PMEVN_SWITCH(n, RETURN_READ_PMEVTYPERN);
> +	return 0;
> +}
> +
>  static inline unsigned long read_pmmir(void)
>  {
>  	return read_cpuid(PMMIR_EL1);
> @@ -96,6 +104,11 @@ static inline void write_pmccfiltr(u64 val)
>  	write_sysreg(val, pmccfiltr_el0);
>  }
>  
> +static inline u64 read_pmccfiltr(void)
> +{
> +	return read_sysreg(pmccfiltr_el0);
> +}
> +
>  static inline void write_pmovsclr(u64 val)
>  {
>  	write_sysreg(val, pmovsclr_el0);
> diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
> index e633b4434c6a..01c9a9efdd1c 100644
> --- a/arch/arm64/kvm/pmu.c
> +++ b/arch/arm64/kvm/pmu.c
> @@ -6,6 +6,8 @@
>  #include <linux/kvm_host.h>
>  #include <linux/perf_event.h>
>  
> +#include <asm/arm_pmuv3.h>
> +
>  static DEFINE_PER_CPU(struct kvm_pmu_events, kvm_pmu_events);
>  
>  /*
> @@ -62,63 +64,16 @@ void kvm_clr_pmu_events(u64 clr)
>  	pmu->events_guest &= ~clr;
>  }
>  
> -#define PMEVTYPER_READ_CASE(idx)				\
> -	case idx:						\
> -		return read_sysreg(pmevtyper##idx##_el0)
> -
> -#define PMEVTYPER_WRITE_CASE(idx)				\
> -	case idx:						\
> -		write_sysreg(val, pmevtyper##idx##_el0);	\
> -		break
> -
> -#define PMEVTYPER_CASES(readwrite)				\
> -	PMEVTYPER_##readwrite##_CASE(0);			\
> -	PMEVTYPER_##readwrite##_CASE(1);			\
> -	PMEVTYPER_##readwrite##_CASE(2);			\
> -	PMEVTYPER_##readwrite##_CASE(3);			\
> -	PMEVTYPER_##readwrite##_CASE(4);			\
> -	PMEVTYPER_##readwrite##_CASE(5);			\
> -	PMEVTYPER_##readwrite##_CASE(6);			\
> -	PMEVTYPER_##readwrite##_CASE(7);			\
> -	PMEVTYPER_##readwrite##_CASE(8);			\
> -	PMEVTYPER_##readwrite##_CASE(9);			\
> -	PMEVTYPER_##readwrite##_CASE(10);			\
> -	PMEVTYPER_##readwrite##_CASE(11);			\
> -	PMEVTYPER_##readwrite##_CASE(12);			\
> -	PMEVTYPER_##readwrite##_CASE(13);			\
> -	PMEVTYPER_##readwrite##_CASE(14);			\
> -	PMEVTYPER_##readwrite##_CASE(15);			\
> -	PMEVTYPER_##readwrite##_CASE(16);			\
> -	PMEVTYPER_##readwrite##_CASE(17);			\
> -	PMEVTYPER_##readwrite##_CASE(18);			\
> -	PMEVTYPER_##readwrite##_CASE(19);			\
> -	PMEVTYPER_##readwrite##_CASE(20);			\
> -	PMEVTYPER_##readwrite##_CASE(21);			\
> -	PMEVTYPER_##readwrite##_CASE(22);			\
> -	PMEVTYPER_##readwrite##_CASE(23);			\
> -	PMEVTYPER_##readwrite##_CASE(24);			\
> -	PMEVTYPER_##readwrite##_CASE(25);			\
> -	PMEVTYPER_##readwrite##_CASE(26);			\
> -	PMEVTYPER_##readwrite##_CASE(27);			\
> -	PMEVTYPER_##readwrite##_CASE(28);			\
> -	PMEVTYPER_##readwrite##_CASE(29);			\
> -	PMEVTYPER_##readwrite##_CASE(30)
> -
>  /*
>   * Read a value direct from PMEVTYPER<idx> where idx is 0-30
>   * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31).
>   */
>  static u64 kvm_vcpu_pmu_read_evtype_direct(int idx)
>  {
> -	switch (idx) {
> -	PMEVTYPER_CASES(READ);
> -	case ARMV8_PMU_CYCLE_IDX:
> -		return read_sysreg(pmccfiltr_el0);
> -	default:
> -		WARN_ON(1);
> -	}
> +	if (idx == ARMV8_PMU_CYCLE_IDX)
> +		return read_pmccfiltr();
>  
> -	return 0;
> +	return read_pmevtypern(idx);
>  }
>  
>  /*
> @@ -127,14 +82,10 @@ static u64 kvm_vcpu_pmu_read_evtype_direct(int idx)
>   */
>  static void kvm_vcpu_pmu_write_evtype_direct(int idx, u32 val)
>  {
> -	switch (idx) {
> -	PMEVTYPER_CASES(WRITE);
> -	case ARMV8_PMU_CYCLE_IDX:
> -		write_sysreg(val, pmccfiltr_el0);
> -		break;
> -	default:
> -		WARN_ON(1);
> -	}
> +	if (idx == ARMV8_PMU_CYCLE_IDX)
> +		write_pmccfiltr(val);
> +	else
> +		write_pmevtypern(idx, val);
>  }
>  
>  /*
> 
> -- 
> 2.43.0
>