[PATCH v5 05/12] KVM: arm64: PMU: Simplify extracting PMCR_EL0.N

Raghavendra Rao Ananta
2023-08-17T00:31:31Z

From: Reiji Watanabe <reijiw@google.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@google.com>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.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