linux-kernel - [PATCH v5 05/12] KVM: arm64: PMU: Simplify extracting PMCR

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Message-ID: <20230817003029.3073210-6-rananta@google.com>
Date:   Thu, 17 Aug 2023 00:30:22 +0000
From:   Raghavendra Rao Ananta <rananta@...gle.com>
To:     Oliver Upton <oliver.upton@...ux.dev>,
        Marc Zyngier <maz@...nel.org>
Cc:     Alexandru Elisei <alexandru.elisei@....com>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Zenghui Yu <yuzenghui@...wei.com>,
        Shaoqin Huang <shahuang@...hat.com>,
        Jing Zhang <jingzhangos@...gle.com>,
        Reiji Watanabe <reijiw@...gle.com>,
        Colton Lewis <coltonlewis@...gle.com>,
        Raghavendra Rao Anata <rananta@...gle.com>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH v5 05/12] KVM: arm64: PMU: Simplify extracting PMCR_EL0.N

From: Reiji Watanabe <reijiw@...gle.com>

Some code extracts PMCR_EL0.N using ARMV8_PMU_PMCR_N_SHIFT and
ARMV8_PMU_PMCR_N_MASK. Define ARMV8_PMU_PMCR_N (0x1f << 11),
and simplify those codes using FIELD_GET() and/or ARMV8_PMU_PMCR_N.
The following patches will also use these macros to extract PMCR_EL0.N.

No functional change intended.

Signed-off-by: Reiji Watanabe <reijiw@...gle.com>
Signed-off-by: Raghavendra Rao Ananta <rananta@...gle.com>
---
 arch/arm64/kvm/pmu-emul.c      | 3 +--
 arch/arm64/kvm/sys_regs.c      | 7 +++----
 drivers/perf/arm_pmuv3.c       | 3 +--
 include/linux/perf/arm_pmuv3.h | 2 +-
 4 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index b87822024828a..f7b5fa16341ad 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -245,9 +245,8 @@ void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu)
 
 u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
 {
-	u64 val = __vcpu_sys_reg(vcpu, PMCR_EL0) >> ARMV8_PMU_PMCR_N_SHIFT;
+	u64 val = FIELD_GET(ARMV8_PMU_PMCR_N, __vcpu_sys_reg(vcpu, PMCR_EL0));
 
-	val &= ARMV8_PMU_PMCR_N_MASK;
 	if (val == 0)
 		return BIT(ARMV8_PMU_CYCLE_IDX);
 	else
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 39e9248c935e7..30108f09e088b 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -750,7 +750,7 @@ static u64 reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 		return 0;
 
 	/* Only preserve PMCR_EL0.N, and reset the rest to 0 */
-	pmcr = read_sysreg(pmcr_el0) & (ARMV8_PMU_PMCR_N_MASK << ARMV8_PMU_PMCR_N_SHIFT);
+	pmcr = read_sysreg(pmcr_el0) & ARMV8_PMU_PMCR_N;
 	if (!kvm_supports_32bit_el0())
 		pmcr |= ARMV8_PMU_PMCR_LC;
 
@@ -858,10 +858,9 @@ static bool access_pmceid(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 
 static bool pmu_counter_idx_valid(struct kvm_vcpu *vcpu, u64 idx)
 {
-	u64 pmcr, val;
+	u64 val;
 
-	pmcr = __vcpu_sys_reg(vcpu, PMCR_EL0);
-	val = (pmcr >> ARMV8_PMU_PMCR_N_SHIFT) & ARMV8_PMU_PMCR_N_MASK;
+	val = FIELD_GET(ARMV8_PMU_PMCR_N, __vcpu_sys_reg(vcpu, PMCR_EL0));
 	if (idx >= val && idx != ARMV8_PMU_CYCLE_IDX) {
 		kvm_inject_undefined(vcpu);
 		return false;
diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c
index 08b3a1bf0ef62..7618b0adc0b8c 100644
--- a/drivers/perf/arm_pmuv3.c
+++ b/drivers/perf/arm_pmuv3.c
@@ -1128,8 +1128,7 @@ static void __armv8pmu_probe_pmu(void *info)
 	probe->present = true;
 
 	/* Read the nb of CNTx counters supported from PMNC */
-	cpu_pmu->num_events = (armv8pmu_pmcr_read() >> ARMV8_PMU_PMCR_N_SHIFT)
-		& ARMV8_PMU_PMCR_N_MASK;
+	cpu_pmu->num_events = FIELD_GET(ARMV8_PMU_PMCR_N, armv8pmu_pmcr_read());
 
 	/* Add the CPU cycles counter */
 	cpu_pmu->num_events += 1;
diff --git a/include/linux/perf/arm_pmuv3.h b/include/linux/perf/arm_pmuv3.h
index e3899bd77f5cc..ecbcf3f93560c 100644
--- a/include/linux/perf/arm_pmuv3.h
+++ b/include/linux/perf/arm_pmuv3.h
@@ -216,7 +216,7 @@
 #define ARMV8_PMU_PMCR_LC	(1 << 6) /* Overflow on 64 bit cycle counter */
 #define ARMV8_PMU_PMCR_LP	(1 << 7) /* Long event counter enable */
 #define ARMV8_PMU_PMCR_N_SHIFT	11  /* Number of counters supported */
-#define ARMV8_PMU_PMCR_N_MASK	0x1f
+#define	ARMV8_PMU_PMCR_N	(0x1f << ARMV8_PMU_PMCR_N_SHIFT)
 #define ARMV8_PMU_PMCR_MASK	0xff    /* Mask for writable bits */
 
 /*
-- 
2.41.0.694.ge786442a9b-goog