[PATCH v7 14/19] KVM: ARM64: Add helper to handle PMCR register bits

Shannon Zhao
2015-12-15T08:49:34Z

From: Shannon Zhao <shannon.zhao@linaro.org>

According to ARMv8 spec, when writing 1 to PMCR.E, all counters are
enabled by PMCNTENSET, while writing 0 to PMCR.E, all counters are
disabled. When writing 1 to PMCR.P, reset all event counters, not
including PMCCNTR, to zero. When writing 1 to PMCR.C, reset PMCCNTR to
zero.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
---
arch/arm64/kvm/sys_regs.c | 1 +
include/kvm/arm_pmu.h | 2 ++
virt/kvm/arm/pmu.c | 40 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 43 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index f09e500..b2ccc25 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -463,6 +463,7 @@ static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
val &= ~ARMV8_PMCR_MASK;
val |= p->regval & ARMV8_PMCR_MASK;
vcpu_sys_reg(vcpu, r->reg) = val;
+ kvm_pmu_handle_pmcr(vcpu, val);
} else {
/* PMCR.P & PMCR.C are RAZ */
val = vcpu_sys_reg(vcpu, r->reg)
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index f5888eb..25b5f98 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -42,6 +42,7 @@ void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val);
void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val);
void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
u64 select_idx);
+void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val);
#else
struct kvm_pmu {
};
@@ -56,6 +57,7 @@ void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val) {}
void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val) {}
void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
u64 select_idx) {}
+void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val) {}
#endif

#endif
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 01af727..e664721 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -130,6 +130,46 @@ void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val)
}

/**
+ * kvm_pmu_handle_pmcr - handle PMCR register
+ * @vcpu: The vcpu pointer
+ * @val: the value guest writes to PMCR register
+ */
+void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
+{
+ struct kvm_pmu *pmu = &vcpu->arch.pmu;
+ struct kvm_pmc *pmc;
+ int i;
+
+ if (val & ARMV8_PMCR_E) {
+ kvm_pmu_enable_counter(vcpu,
+ vcpu_sys_reg(vcpu, PMCNTENSET_EL0));
+ } else {
+ kvm_pmu_disable_counter(vcpu, 0xffffffffUL);
+ }
+
+ if (val & ARMV8_PMCR_C) {
+ pmc = &pmu->pmc[ARMV8_CYCLE_IDX];
+ if (pmc->perf_event)
+ local64_set(&pmc->perf_event->count, 0);
+ vcpu_sys_reg(vcpu, PMCCNTR_EL0) = 0;
+ }
+
+ if (val & ARMV8_PMCR_P) {
+ for (i = 0; i < ARMV8_CYCLE_IDX; i++) {
+ pmc = &pmu->pmc[i];
+ if (pmc->perf_event)
+ local64_set(&pmc->perf_event->count, 0);
+ vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) = 0;
+ }
+ }
+
+ if (val & ARMV8_PMCR_LC) {
+ pmc = &pmu->pmc[ARMV8_CYCLE_IDX];
+ pmc->bitmask = 0xffffffffffffffffUL;
+ }
+}
+
+/**
* kvm_pmu_overflow_set - set PMU overflow interrupt
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMOVSSET register
--
2.0.4