[PATCH v3 07/14] KVM: arm64: PMU: Simplify extracting PMCR_EL0.N

[Reiji Watanabe]

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 at google.com>
---
 arch/arm64/include/asm/perf_event.h | 2 +-
 arch/arm64/kernel/perf_event.c      | 3 +--
 arch/arm64/kvm/pmu-emul.c           | 3 +--
 arch/arm64/kvm/sys_regs.c           | 7 +++----
 4 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h
index 3eaf462f5752..eeef8d56d9c8 100644
--- a/arch/arm64/include/asm/perf_event.h
+++ b/arch/arm64/include/asm/perf_event.h
@@ -219,7 +219,7 @@
 #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 */
 
 /*
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index a5193f2146a6..1775d89a9144 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -1158,8 +1158,7 @@ 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/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 701728ad78d6..9dbf532e264e 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -246,9 +246,8 @@ 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 790f028a1686..9b410a2ea20c 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -629,7 +629,7 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 		return;
 
 	/* 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;
 
@@ -736,10 +736,9 @@ 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;
-- 
2.39.1.519.gcb327c4b5f-goog