1 files changed, 215 insertions, 37 deletions

diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 24c6cf869a16..3dd8238ed246 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -15,6 +15,8 @@
 
 static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx);
 
+#define PERF_ATTR_CFG1_KVM_PMU_CHAINED 0x1
+
 /**
  * kvm_pmu_idx_is_64bit - determine if select_idx is a 64bit counter
  * @vcpu: The vcpu pointer
@@ -26,29 +28,126 @@ static bool kvm_pmu_idx_is_64bit(struct kvm_vcpu *vcpu, u64 select_idx)
 		__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_LC);
 }
 
+static struct kvm_vcpu *kvm_pmc_to_vcpu(struct kvm_pmc *pmc)
+{
+	struct kvm_pmu *pmu;
+	struct kvm_vcpu_arch *vcpu_arch;
+
+	pmc -= pmc->idx;
+	pmu = container_of(pmc, struct kvm_pmu, pmc[0]);
+	vcpu_arch = container_of(pmu, struct kvm_vcpu_arch, pmu);
+	return container_of(vcpu_arch, struct kvm_vcpu, arch);
+}
+
 /**
- * kvm_pmu_get_counter_value - get PMU counter value
+ * kvm_pmu_pmc_is_chained - determine if the pmc is chained
+ * @pmc: The PMU counter pointer
+ */
+static bool kvm_pmu_pmc_is_chained(struct kvm_pmc *pmc)
+{
+	struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
+
+	return test_bit(pmc->idx >> 1, vcpu->arch.pmu.chained);
+}
+
+/**
+ * kvm_pmu_idx_is_high_counter - determine if select_idx is a high/low counter
+ * @select_idx: The counter index
+ */
+static bool kvm_pmu_idx_is_high_counter(u64 select_idx)
+{
+	return select_idx & 0x1;
+}
+
+/**
+ * kvm_pmu_get_canonical_pmc - obtain the canonical pmc
+ * @pmc: The PMU counter pointer
+ *
+ * When a pair of PMCs are chained together we use the low counter (canonical)
+ * to hold the underlying perf event.
+ */
+static struct kvm_pmc *kvm_pmu_get_canonical_pmc(struct kvm_pmc *pmc)
+{
+	if (kvm_pmu_pmc_is_chained(pmc) &&
+	    kvm_pmu_idx_is_high_counter(pmc->idx))
+		return pmc - 1;
+
+	return pmc;
+}
+
+/**
+ * kvm_pmu_idx_has_chain_evtype - determine if the event type is chain
  * @vcpu: The vcpu pointer
  * @select_idx: The counter index
  */
-u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
+static bool kvm_pmu_idx_has_chain_evtype(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];
+	u64 eventsel, reg;
 
-	reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
-	      ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_idx;
-	counter = __vcpu_sys_reg(vcpu, reg);
+	select_idx |= 0x1;
+
+	if (select_idx == ARMV8_PMU_CYCLE_IDX)
+		return false;
+
+	reg = PMEVTYPER0_EL0 + select_idx;
+	eventsel = __vcpu_sys_reg(vcpu, reg) & ARMV8_PMU_EVTYPE_EVENT;
+
+	return eventsel == ARMV8_PMUV3_PERFCTR_CHAIN;
+}
+
+/**
+ * kvm_pmu_get_pair_counter_value - get PMU counter value
+ * @vcpu: The vcpu pointer
+ * @pmc: The PMU counter pointer
+ */
+static u64 kvm_pmu_get_pair_counter_value(struct kvm_vcpu *vcpu,
+					  struct kvm_pmc *pmc)
+{
+	u64 counter, counter_high, reg, enabled, running;
 
-	/* The real counter value is equal to the value of counter register plus
+	if (kvm_pmu_pmc_is_chained(pmc)) {
+		pmc = kvm_pmu_get_canonical_pmc(pmc);
+		reg = PMEVCNTR0_EL0 + pmc->idx;
+
+		counter = __vcpu_sys_reg(vcpu, reg);
+		counter_high = __vcpu_sys_reg(vcpu, reg + 1);
+
+		counter = lower_32_bits(counter) | (counter_high << 32);
+	} else {
+		reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)
+		      ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + pmc->idx;
+		counter = __vcpu_sys_reg(vcpu, reg);
+	}
+
+	/*
+	 * The real counter value is equal to the value of counter register plus
 	 * the value perf event counts.
 	 */
 	if (pmc->perf_event)
 		counter += perf_event_read_value(pmc->perf_event, &enabled,
 						 &running);
 
-	if (!kvm_pmu_idx_is_64bit(vcpu, select_idx))
+	return counter;
+}
+
+/**
+ * kvm_pmu_get_counter_value - get PMU counter value
+ * @vcpu: The vcpu pointer
+ * @select_idx: The counter index
+ */
+u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
+{
+	u64 counter;
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+	struct kvm_pmc *pmc = &pmu->pmc[select_idx];
+
+	counter = kvm_pmu_get_pair_counter_value(vcpu, pmc);
+
+	if (kvm_pmu_pmc_is_chained(pmc) &&
+	    kvm_pmu_idx_is_high_counter(select_idx))
+		counter = upper_32_bits(counter);
+
+	else if (!kvm_pmu_idx_is_64bit(vcpu, select_idx))
 		counter = lower_32_bits(counter);
 
 	return counter;
@@ -78,6 +177,7 @@ void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val)
  */
 static void kvm_pmu_release_perf_event(struct kvm_pmc *pmc)
 {
+	pmc = kvm_pmu_get_canonical_pmc(pmc);
 	if (pmc->perf_event) {
 		perf_event_disable(pmc->perf_event);
 		perf_event_release_kernel(pmc->perf_event);
@@ -95,13 +195,23 @@ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
 {
 	u64 counter, reg;
 
-	if (pmc->perf_event) {
-		counter = kvm_pmu_get_counter_value(vcpu, pmc->idx);
+	pmc = kvm_pmu_get_canonical_pmc(pmc);
+	if (!pmc->perf_event)
+		return;
+
+	counter = kvm_pmu_get_pair_counter_value(vcpu, pmc);
+
+	if (kvm_pmu_pmc_is_chained(pmc)) {
+		reg = PMEVCNTR0_EL0 + pmc->idx;
+		__vcpu_sys_reg(vcpu, reg) = lower_32_bits(counter);
+		__vcpu_sys_reg(vcpu, reg + 1) = upper_32_bits(counter);
+	} else {
 		reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)
 		       ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + pmc->idx;
-		__vcpu_sys_reg(vcpu, reg) = counter;
-		kvm_pmu_release_perf_event(pmc);
+		__vcpu_sys_reg(vcpu, reg) = lower_32_bits(counter);
 	}
+
+	kvm_pmu_release_perf_event(pmc);
 }
 
 /**
@@ -118,6 +228,8 @@ void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
 		kvm_pmu_stop_counter(vcpu, &pmu->pmc[i]);
 		pmu->pmc[i].idx = i;
 	}
+
+	bitmap_zero(vcpu->arch.pmu.chained, ARMV8_PMU_MAX_COUNTER_PAIRS);
 }
 
 /**
@@ -166,6 +278,18 @@ void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
 			continue;
 
 		pmc = &pmu->pmc[i];
+
+		/*
+		 * For high counters of chained events we must recreate the
+		 * perf event with the long (64bit) attribute set.
+		 */
+		if (kvm_pmu_pmc_is_chained(pmc) &&
+		    kvm_pmu_idx_is_high_counter(i)) {
+			kvm_pmu_create_perf_event(vcpu, i);
+			continue;
+		}
+
+		/* At this point, pmc must be the canonical */
 		if (pmc->perf_event) {
 			perf_event_enable(pmc->perf_event);
 			if (pmc->perf_event->state != PERF_EVENT_STATE_ACTIVE)
@@ -195,6 +319,18 @@ void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
 			continue;
 
 		pmc = &pmu->pmc[i];
+
+		/*
+		 * For high counters of chained events we must recreate the
+		 * perf event with the long (64bit) attribute unset.
+		 */
+		if (kvm_pmu_pmc_is_chained(pmc) &&
+		    kvm_pmu_idx_is_high_counter(i)) {
+			kvm_pmu_create_perf_event(vcpu, i);
+			continue;
+		}
+
+		/* At this point, pmc must be the canonical */
 		if (pmc->perf_event)
 			perf_event_disable(pmc->perf_event);
 	}
@@ -284,17 +420,6 @@ void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu)
 	kvm_pmu_update_state(vcpu);
 }
 
-static inline struct kvm_vcpu *kvm_pmc_to_vcpu(struct kvm_pmc *pmc)
-{
-	struct kvm_pmu *pmu;
-	struct kvm_vcpu_arch *vcpu_arch;
-
-	pmc -= pmc->idx;
-	pmu = container_of(pmc, struct kvm_pmu, pmc[0]);
-	vcpu_arch = container_of(pmu, struct kvm_vcpu_arch, pmu);
-	return container_of(vcpu_arch, struct kvm_vcpu, arch);
-}
-
 /**
  * When the perf event overflows, set the overflow status and inform the vcpu.
  */
@@ -385,13 +510,20 @@ 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;
 	struct perf_event *event;
 	struct perf_event_attr attr;
 	u64 eventsel, counter, reg, data;
 
-	reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
-	      ? PMCCFILTR_EL0 : PMEVTYPER0_EL0 + select_idx;
+	/*
+	 * For chained counters the event type and filtering attributes are
+	 * obtained from the low/even counter. We also use this counter to
+	 * determine if the event is enabled/disabled.
+	 */
+	pmc = kvm_pmu_get_canonical_pmc(&pmu->pmc[select_idx]);
+
+	reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)
+	      ? PMCCFILTR_EL0 : PMEVTYPER0_EL0 + pmc->idx;
 	data = __vcpu_sys_reg(vcpu, reg);
 
 	kvm_pmu_stop_counter(vcpu, pmc);
@@ -399,30 +531,47 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
 
 	/* Software increment event does't need to be backed by a perf event */
 	if (eventsel == ARMV8_PMUV3_PERFCTR_SW_INCR &&
-	    select_idx != ARMV8_PMU_CYCLE_IDX)
+	    pmc->idx != ARMV8_PMU_CYCLE_IDX)
 		return;
 
 	memset(&attr, 0, sizeof(struct perf_event_attr));
 	attr.type = PERF_TYPE_RAW;
 	attr.size = sizeof(attr);
 	attr.pinned = 1;
-	attr.disabled = !kvm_pmu_counter_is_enabled(vcpu, select_idx);
+	attr.disabled = !kvm_pmu_counter_is_enabled(vcpu, pmc->idx);
 	attr.exclude_user = data & ARMV8_PMU_EXCLUDE_EL0 ? 1 : 0;
 	attr.exclude_kernel = data & ARMV8_PMU_EXCLUDE_EL1 ? 1 : 0;
 	attr.exclude_hv = 1; /* Don't count EL2 events */
 	attr.exclude_host = 1; /* Don't count host events */
-	attr.config = (select_idx == ARMV8_PMU_CYCLE_IDX) ?
+	attr.config = (pmc->idx == ARMV8_PMU_CYCLE_IDX) ?
 		ARMV8_PMUV3_PERFCTR_CPU_CYCLES : eventsel;
 
-	counter = kvm_pmu_get_counter_value(vcpu, select_idx);
-	/* The initial sample period (overflow count) of an event. */
-	if (kvm_pmu_idx_is_64bit(vcpu, pmc->idx))
+	counter = kvm_pmu_get_pair_counter_value(vcpu, pmc);
+
+	if (kvm_pmu_idx_has_chain_evtype(vcpu, pmc->idx)) {
+		/**
+		 * The initial sample period (overflow count) of an event. For
+		 * chained counters we only support overflow interrupts on the
+		 * high counter.
+		 */
 		attr.sample_period = (-counter) & GENMASK(63, 0);
-	else
-		attr.sample_period = (-counter) & GENMASK(31, 0);
+		event = perf_event_create_kernel_counter(&attr, -1, current,
+							 kvm_pmu_perf_overflow,
+							 pmc + 1);
+
+		if (kvm_pmu_counter_is_enabled(vcpu, pmc->idx + 1))
+			attr.config1 |= PERF_ATTR_CFG1_KVM_PMU_CHAINED;
+	} else {
+		/* The initial sample period (overflow count) of an event. */
+		if (kvm_pmu_idx_is_64bit(vcpu, pmc->idx))
+			attr.sample_period = (-counter) & GENMASK(63, 0);
+		else
+			attr.sample_period = (-counter) & GENMASK(31, 0);
 
-	event = perf_event_create_kernel_counter(&attr, -1, current,
+		event = perf_event_create_kernel_counter(&attr, -1, current,
 						 kvm_pmu_perf_overflow, pmc);
+	}
+
 	if (IS_ERR(event)) {
 		pr_err_once("kvm: pmu event creation failed %ld\n",
 			    PTR_ERR(event));
@@ -433,6 +582,33 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
 }
 
 /**
+ * kvm_pmu_update_pmc_chained - update chained bitmap
+ * @vcpu: The vcpu pointer
+ * @select_idx: The number of selected counter
+ *
+ * Update the chained bitmap based on the event type written in the
+ * typer register.
+ */
+static void kvm_pmu_update_pmc_chained(struct kvm_vcpu *vcpu, u64 select_idx)
+{
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+	struct kvm_pmc *pmc = &pmu->pmc[select_idx];
+
+	if (kvm_pmu_idx_has_chain_evtype(vcpu, pmc->idx)) {
+		/*
+		 * During promotion from !chained to chained we must ensure
+		 * the adjacent counter is stopped and its event destroyed
+		 */
+		if (!kvm_pmu_pmc_is_chained(pmc))
+			kvm_pmu_stop_counter(vcpu, pmc);
+
+		set_bit(pmc->idx >> 1, vcpu->arch.pmu.chained);
+	} else {
+		clear_bit(pmc->idx >> 1, vcpu->arch.pmu.chained);
+	}
+}
+
+/**
  * kvm_pmu_set_counter_event_type - set selected counter to monitor some event
  * @vcpu: The vcpu pointer
  * @data: The data guest writes to PMXEVTYPER_EL0
@@ -451,6 +627,8 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
 	      ? PMCCFILTR_EL0 : PMEVTYPER0_EL0 + select_idx;
 
 	__vcpu_sys_reg(vcpu, reg) = event_type;
+
+	kvm_pmu_update_pmc_chained(vcpu, select_idx);
 	kvm_pmu_create_perf_event(vcpu, select_idx);
 }