The CHAIN PMU event implicitly creates a relationship between a pair
of adjacent counters, this is due to the high counter counting overflows
occurring in the low counter.
To facilitate emulation of chained counters let's represent this
relationship via a struct kvm_pmc_pair that holds a pair of counters.
Signed-off-by: Andrew Murray <andrew.murray@xxxxxxx>
---
include/kvm/arm_pmu.h | 13 +++++++-
virt/kvm/arm/pmu.c | 78 ++++++++++++++++++++++++++++++++-----------
2 files changed, 71 insertions(+), 20 deletions(-)
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index b73f31baca52..ee80dc8db990 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -22,6 +22,7 @@
#include <asm/perf_event.h>
#define ARMV8_PMU_CYCLE_IDX (ARMV8_PMU_MAX_COUNTERS - 1)
+#define ARMV8_PMU_MAX_COUNTER_PAIRS ((ARMV8_PMU_MAX_COUNTERS + 1) >> 1)
#ifdef CONFIG_KVM_ARM_PMU
@@ -31,9 +32,19 @@ struct kvm_pmc {
u64 bitmask;
};
+enum kvm_pmc_type {
+ KVM_PMC_TYPE_PAIR,
+};
+
+struct kvm_pmc_pair {
+ struct kvm_pmc low;
+ struct kvm_pmc high;
+ enum kvm_pmc_type type;
+};
+
struct kvm_pmu {
int irq_num;
- struct kvm_pmc pmc[ARMV8_PMU_MAX_COUNTERS];
+ struct kvm_pmc_pair pmc_pair[ARMV8_PMU_MAX_COUNTER_PAIRS];
bool ready;
bool created;
bool irq_level;
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index ae1e886d4a1a..08acd60c538a 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -25,6 +25,43 @@
#include <kvm/arm_vgic.h>
static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx);
+
+/**
+ * kvm_pmu_pair_is_high_counter - determine if select_idx is a high/low counter
+ * @select_idx: The counter index
+ */
+static bool kvm_pmu_pair_is_high_counter(u64 select_idx)
+{
+ return select_idx & 0x1;
+}
+
+/**
+ * kvm_pmu_get_kvm_pmc_pair - obtain a pmc_pair from a pmc
+ * @pmc: The PMU counter pointer
+ */
+static struct kvm_pmc_pair *kvm_pmu_get_kvm_pmc_pair(struct kvm_pmc *pmc)
+{
+ if (kvm_pmu_pair_is_high_counter(pmc->idx))
+ return container_of(pmc, struct kvm_pmc_pair, high);
+ else
+ return container_of(pmc, struct kvm_pmc_pair, low);
+}
+
+/**
+ * kvm_pmu_get_kvm_pmc - obtain a pmc based on select_idx
+ * @vcpu: The vcpu pointer
+ * @select_idx: The counter index
+ */
+static struct kvm_pmc *kvm_pmu_get_kvm_pmc(struct kvm_vcpu *vcpu,
+ u64 select_idx)
+{
+ struct kvm_pmu *pmu = &vcpu->arch.pmu;
+ struct kvm_pmc_pair *pmc_pair = &pmu->pmc_pair[select_idx >> 1];
+
+ return kvm_pmu_pair_is_high_counter(select_idx) ? &pmc_pair->high
+ : &pmc_pair->low;
+}
+
/**
* kvm_pmu_get_counter_value - get PMU counter value
* @vcpu: The vcpu pointer
@@ -33,8 +70,7 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx);
u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
{
u64 counter, reg, enabled, running;
- struct kvm_pmu *pmu = &vcpu->arch.pmu;
- struct kvm_pmc *pmc = &pmu->pmc[select_idx];
+ struct kvm_pmc *pmc = kvm_pmu_get_kvm_pmc(vcpu, select_idx);
reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_idx;
@@ -108,12 +144,17 @@ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
{
int i;
- struct kvm_pmu *pmu = &vcpu->arch.pmu;
+ struct kvm_pmc *pmc;
+ struct kvm_pmc_pair *pmc_pair;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
- kvm_pmu_stop_counter(vcpu, &pmu->pmc[i]);
- pmu->pmc[i].idx = i;
- pmu->pmc[i].bitmask = 0xffffffffUL;
+ pmc = kvm_pmu_get_kvm_pmc(vcpu, i);
+ kvm_pmu_stop_counter(vcpu, pmc);
+ pmc->idx = i;
+ pmc->bitmask = 0xffffffffUL;
+
+ pmc_pair = kvm_pmu_get_kvm_pmc_pair(pmc);
+ pmc_pair->type = KVM_PMC_TYPE_PAIR;
}
}
@@ -125,10 +166,12 @@ void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu)
{
int i;
- struct kvm_pmu *pmu = &vcpu->arch.pmu;
+ struct kvm_pmc *pmc;
- for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
- kvm_pmu_release_perf_event(&pmu->pmc[i]);
+ for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
+ pmc = kvm_pmu_get_kvm_pmc(vcpu, i);
+ kvm_pmu_release_perf_event(pmc);
+ }
}
u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
@@ -152,7 +195,6 @@ u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
{
int i;
- struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) || !val)
@@ -162,7 +204,7 @@ void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
if (!(val & BIT(i)))
continue;
- pmc = &pmu->pmc[i];
+ pmc = kvm_pmu_get_kvm_pmc(vcpu, i);
if (pmc->perf_event) {
perf_event_enable(pmc->perf_event);
if (pmc->perf_event->state != PERF_EVENT_STATE_ACTIVE)
@@ -181,7 +223,6 @@ void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
{
int i;
- struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
if (!val)
@@ -191,7 +232,7 @@ void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
if (!(val & BIT(i)))
continue;
- pmc = &pmu->pmc[i];
+ pmc = kvm_pmu_get_kvm_pmc(vcpu, i);
if (pmc->perf_event)
perf_event_disable(pmc->perf_event);
}
@@ -285,9 +326,10 @@ static inline struct kvm_vcpu *kvm_pmc_to_vcpu(struct kvm_pmc *pmc)
{
struct kvm_pmu *pmu;
struct kvm_vcpu_arch *vcpu_arch;
+ struct kvm_pmc_pair *pair = kvm_pmu_get_kvm_pmc_pair(pmc);
- pmc -= pmc->idx;
- pmu = container_of(pmc, struct kvm_pmu, pmc[0]);
+ pair -= (pmc->idx >> 1);
+ pmu = container_of(pair, struct kvm_pmu, pmc_pair[0]);
vcpu_arch = container_of(pmu, struct kvm_vcpu_arch, pmu);
return container_of(vcpu_arch, struct kvm_vcpu, arch);
}
@@ -348,7 +390,6 @@ void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
*/
void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
{
- struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
u64 mask;
int i;
@@ -370,7 +411,7 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
}
if (val & ARMV8_PMU_PMCR_LC) {
- pmc = &pmu->pmc[ARMV8_PMU_CYCLE_IDX];
+ pmc = kvm_pmu_get_kvm_pmc(vcpu, ARMV8_PMU_CYCLE_IDX);
pmc->bitmask = 0xffffffffffffffffUL;
}
}
@@ -388,8 +429,7 @@ static bool kvm_pmu_counter_is_enabled(struct kvm_vcpu *vcpu, u64 select_idx)
*/
static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
{
- struct kvm_pmu *pmu = &vcpu->arch.pmu;
- struct kvm_pmc *pmc = &pmu->pmc[select_idx];
+ struct kvm_pmc *pmc = kvm_pmu_get_kvm_pmc(vcpu, select_idx);
struct perf_event *event;
struct perf_event_attr attr;
u64 eventsel, counter, reg, data;
--
2.21.0
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