Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1016 insertions, 0 deletions

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
new file mode 100644
index 000000000..c7e5f6a28
--- /dev/null
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -0,0 +1,1016 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015 Linaro Ltd.
+ * Author: Shannon Zhao <shannon.zhao@linaro.org>
+ */
+
+#include <linux/cpu.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/list.h>
+#include <linux/perf_event.h>
+#include <linux/perf/arm_pmu.h>
+#include <linux/uaccess.h>
+#include <asm/kvm_emulate.h>
+#include <kvm/arm_pmu.h>
+#include <kvm/arm_vgic.h>
+
+#define PERF_ATTR_CFG1_COUNTER_64BIT	BIT(0)
+
+DEFINE_STATIC_KEY_FALSE(kvm_arm_pmu_available);
+
+static LIST_HEAD(arm_pmus);
+static DEFINE_MUTEX(arm_pmus_lock);
+
+static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx);
+
+static u32 kvm_pmu_event_mask(struct kvm *kvm)
+{
+	unsigned int pmuver;
+
+	pmuver = kvm->arch.arm_pmu->pmuver;
+
+	switch (pmuver) {
+	case ID_AA64DFR0_EL1_PMUVer_IMP:
+		return GENMASK(9, 0);
+	case ID_AA64DFR0_EL1_PMUVer_V3P1:
+	case ID_AA64DFR0_EL1_PMUVer_V3P4:
+	case ID_AA64DFR0_EL1_PMUVer_V3P5:
+	case ID_AA64DFR0_EL1_PMUVer_V3P7:
+		return GENMASK(15, 0);
+	default:		/* Shouldn't be here, just for sanity */
+		WARN_ONCE(1, "Unknown PMU version %d\n", pmuver);
+		return 0;
+	}
+}
+
+/**
+ * kvm_pmu_idx_is_64bit - determine if select_idx is a 64bit counter
+ * @vcpu: The vcpu pointer
+ * @select_idx: The counter index
+ */
+static bool kvm_pmu_idx_is_64bit(struct kvm_vcpu *vcpu, u64 select_idx)
+{
+	return (select_idx == ARMV8_PMU_CYCLE_IDX);
+}
+
+static bool kvm_pmu_idx_has_64bit_overflow(struct kvm_vcpu *vcpu, u64 select_idx)
+{
+	return (select_idx == ARMV8_PMU_CYCLE_IDX &&
+		__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_LC);
+}
+
+static bool kvm_pmu_counter_can_chain(struct kvm_vcpu *vcpu, u64 idx)
+{
+	return (!(idx & 1) && (idx + 1) < ARMV8_PMU_CYCLE_IDX &&
+		!kvm_pmu_idx_has_64bit_overflow(vcpu, idx));
+}
+
+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
+ * @vcpu: The vcpu pointer
+ * @select_idx: The counter index
+ */
+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];
+
+	if (!kvm_vcpu_has_pmu(vcpu))
+		return 0;
+
+	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))
+		counter = lower_32_bits(counter);
+
+	return counter;
+}
+
+/**
+ * kvm_pmu_set_counter_value - set PMU counter value
+ * @vcpu: The vcpu pointer
+ * @select_idx: The counter index
+ * @val: The counter value
+ */
+void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val)
+{
+	u64 reg;
+
+	if (!kvm_vcpu_has_pmu(vcpu))
+		return;
+
+	reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
+	      ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_idx;
+	__vcpu_sys_reg(vcpu, reg) += (s64)val - kvm_pmu_get_counter_value(vcpu, select_idx);
+
+	/* Recreate the perf event to reflect the updated sample_period */
+	kvm_pmu_create_perf_event(vcpu, select_idx);
+}
+
+/**
+ * kvm_pmu_release_perf_event - remove the perf event
+ * @pmc: The PMU counter pointer
+ */
+static void kvm_pmu_release_perf_event(struct kvm_pmc *pmc)
+{
+	if (pmc->perf_event) {
+		perf_event_disable(pmc->perf_event);
+		perf_event_release_kernel(pmc->perf_event);
+		pmc->perf_event = NULL;
+	}
+}
+
+/**
+ * kvm_pmu_stop_counter - stop PMU counter
+ * @pmc: The PMU counter pointer
+ *
+ * If this counter has been configured to monitor some event, release it here.
+ */
+static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
+{
+	u64 counter, reg, val;
+
+	if (!pmc->perf_event)
+		return;
+
+	counter = kvm_pmu_get_counter_value(vcpu, pmc->idx);
+
+	if (pmc->idx == ARMV8_PMU_CYCLE_IDX) {
+		reg = PMCCNTR_EL0;
+		val = counter;
+	} else {
+		reg = PMEVCNTR0_EL0 + pmc->idx;
+		val = lower_32_bits(counter);
+	}
+
+	__vcpu_sys_reg(vcpu, reg) = val;
+
+	kvm_pmu_release_perf_event(pmc);
+}
+
+/**
+ * kvm_pmu_vcpu_init - assign pmu counter idx for cpu
+ * @vcpu: The vcpu pointer
+ *
+ */
+void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu)
+{
+	int i;
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+
+	for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
+		pmu->pmc[i].idx = i;
+}
+
+/**
+ * kvm_pmu_vcpu_reset - reset pmu state for cpu
+ * @vcpu: The vcpu pointer
+ *
+ */
+void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
+{
+	unsigned long mask = kvm_pmu_valid_counter_mask(vcpu);
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+	int i;
+
+	for_each_set_bit(i, &mask, 32)
+		kvm_pmu_stop_counter(vcpu, &pmu->pmc[i]);
+}
+
+/**
+ * kvm_pmu_vcpu_destroy - free perf event of PMU for cpu
+ * @vcpu: The vcpu pointer
+ *
+ */
+void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu)
+{
+	int i;
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+
+	for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
+		kvm_pmu_release_perf_event(&pmu->pmc[i]);
+	irq_work_sync(&vcpu->arch.pmu.overflow_work);
+}
+
+u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
+{
+	u64 val = __vcpu_sys_reg(vcpu, PMCR_EL0) >> ARMV8_PMU_PMCR_N_SHIFT;
+
+	val &= ARMV8_PMU_PMCR_N_MASK;
+	if (val == 0)
+		return BIT(ARMV8_PMU_CYCLE_IDX);
+	else
+		return GENMASK(val - 1, 0) | BIT(ARMV8_PMU_CYCLE_IDX);
+}
+
+/**
+ * kvm_pmu_enable_counter_mask - enable selected PMU counters
+ * @vcpu: The vcpu pointer
+ * @val: the value guest writes to PMCNTENSET register
+ *
+ * Call perf_event_enable to start counting the perf event
+ */
+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 (!kvm_vcpu_has_pmu(vcpu))
+		return;
+
+	if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) || !val)
+		return;
+
+	for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
+		if (!(val & BIT(i)))
+			continue;
+
+		pmc = &pmu->pmc[i];
+
+		if (!pmc->perf_event) {
+			kvm_pmu_create_perf_event(vcpu, i);
+		} else {
+			perf_event_enable(pmc->perf_event);
+			if (pmc->perf_event->state != PERF_EVENT_STATE_ACTIVE)
+				kvm_debug("fail to enable perf event\n");
+		}
+	}
+}
+
+/**
+ * kvm_pmu_disable_counter_mask - disable selected PMU counters
+ * @vcpu: The vcpu pointer
+ * @val: the value guest writes to PMCNTENCLR register
+ *
+ * Call perf_event_disable to stop counting the perf event
+ */
+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 (!kvm_vcpu_has_pmu(vcpu) || !val)
+		return;
+
+	for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
+		if (!(val & BIT(i)))
+			continue;
+
+		pmc = &pmu->pmc[i];
+
+		if (pmc->perf_event)
+			perf_event_disable(pmc->perf_event);
+	}
+}
+
+static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
+{
+	u64 reg = 0;
+
+	if ((__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E)) {
+		reg = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
+		reg &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
+		reg &= __vcpu_sys_reg(vcpu, PMINTENSET_EL1);
+	}
+
+	return reg;
+}
+
+static void kvm_pmu_update_state(struct kvm_vcpu *vcpu)
+{
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+	bool overflow;
+
+	if (!kvm_vcpu_has_pmu(vcpu))
+		return;
+
+	overflow = !!kvm_pmu_overflow_status(vcpu);
+	if (pmu->irq_level == overflow)
+		return;
+
+	pmu->irq_level = overflow;
+
+	if (likely(irqchip_in_kernel(vcpu->kvm))) {
+		int ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
+					      pmu->irq_num, overflow, pmu);
+		WARN_ON(ret);
+	}
+}
+
+bool kvm_pmu_should_notify_user(struct kvm_vcpu *vcpu)
+{
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+	struct kvm_sync_regs *sregs = &vcpu->run->s.regs;
+	bool run_level = sregs->device_irq_level & KVM_ARM_DEV_PMU;
+
+	if (likely(irqchip_in_kernel(vcpu->kvm)))
+		return false;
+
+	return pmu->irq_level != run_level;
+}
+
+/*
+ * Reflect the PMU overflow interrupt output level into the kvm_run structure
+ */
+void kvm_pmu_update_run(struct kvm_vcpu *vcpu)
+{
+	struct kvm_sync_regs *regs = &vcpu->run->s.regs;
+
+	/* Populate the timer bitmap for user space */
+	regs->device_irq_level &= ~KVM_ARM_DEV_PMU;
+	if (vcpu->arch.pmu.irq_level)
+		regs->device_irq_level |= KVM_ARM_DEV_PMU;
+}
+
+/**
+ * kvm_pmu_flush_hwstate - flush pmu state to cpu
+ * @vcpu: The vcpu pointer
+ *
+ * Check if the PMU has overflowed while we were running in the host, and inject
+ * an interrupt if that was the case.
+ */
+void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu)
+{
+	kvm_pmu_update_state(vcpu);
+}
+
+/**
+ * kvm_pmu_sync_hwstate - sync pmu state from cpu
+ * @vcpu: The vcpu pointer
+ *
+ * Check if the PMU has overflowed while we were running in the guest, and
+ * inject an interrupt if that was the case.
+ */
+void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu)
+{
+	kvm_pmu_update_state(vcpu);
+}
+
+/**
+ * When perf interrupt is an NMI, we cannot safely notify the vcpu corresponding
+ * to the event.
+ * This is why we need a callback to do it once outside of the NMI context.
+ */
+static void kvm_pmu_perf_overflow_notify_vcpu(struct irq_work *work)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_pmu *pmu;
+
+	pmu = container_of(work, struct kvm_pmu, overflow_work);
+	vcpu = kvm_pmc_to_vcpu(pmu->pmc);
+
+	kvm_vcpu_kick(vcpu);
+}
+
+/*
+ * Perform an increment on any of the counters described in @mask,
+ * generating the overflow if required, and propagate it as a chained
+ * event if possible.
+ */
+static void kvm_pmu_counter_increment(struct kvm_vcpu *vcpu,
+				      unsigned long mask, u32 event)
+{
+	int i;
+
+	if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
+		return;
+
+	/* Weed out disabled counters */
+	mask &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
+
+	for_each_set_bit(i, &mask, ARMV8_PMU_CYCLE_IDX) {
+		u64 type, reg;
+
+		/* Filter on event type */
+		type = __vcpu_sys_reg(vcpu, PMEVTYPER0_EL0 + i);
+		type &= kvm_pmu_event_mask(vcpu->kvm);
+		if (type != event)
+			continue;
+
+		/* Increment this counter */
+		reg = __vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) + 1;
+		reg = lower_32_bits(reg);
+		__vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) = reg;
+
+		if (reg) /* No overflow? move on */
+			continue;
+
+		/* Mark overflow */
+		__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(i);
+
+		if (kvm_pmu_counter_can_chain(vcpu, i))
+			kvm_pmu_counter_increment(vcpu, BIT(i + 1),
+						  ARMV8_PMUV3_PERFCTR_CHAIN);
+	}
+}
+
+/* Compute the sample period for a given counter value */
+static u64 compute_period(struct kvm_vcpu *vcpu, u64 select_idx, u64 counter)
+{
+	u64 val;
+
+	if (kvm_pmu_idx_is_64bit(vcpu, select_idx)) {
+		if (!kvm_pmu_idx_has_64bit_overflow(vcpu, select_idx))
+			val = -(counter & GENMASK(31, 0));
+		else
+			val = (-counter) & GENMASK(63, 0);
+	} else {
+		val = (-counter) & GENMASK(31, 0);
+	}
+
+	return val;
+}
+
+/**
+ * When the perf event overflows, set the overflow status and inform the vcpu.
+ */
+static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
+				  struct perf_sample_data *data,
+				  struct pt_regs *regs)
+{
+	struct kvm_pmc *pmc = perf_event->overflow_handler_context;
+	struct arm_pmu *cpu_pmu = to_arm_pmu(perf_event->pmu);
+	struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
+	int idx = pmc->idx;
+	u64 period;
+
+	cpu_pmu->pmu.stop(perf_event, PERF_EF_UPDATE);
+
+	/*
+	 * Reset the sample period to the architectural limit,
+	 * i.e. the point where the counter overflows.
+	 */
+	period = compute_period(vcpu, idx, local64_read(&perf_event->count));
+
+	local64_set(&perf_event->hw.period_left, 0);
+	perf_event->attr.sample_period = period;
+	perf_event->hw.sample_period = period;
+
+	__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(idx);
+
+	if (kvm_pmu_counter_can_chain(vcpu, idx))
+		kvm_pmu_counter_increment(vcpu, BIT(idx + 1),
+					  ARMV8_PMUV3_PERFCTR_CHAIN);
+
+	if (kvm_pmu_overflow_status(vcpu)) {
+		kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
+
+		if (!in_nmi())
+			kvm_vcpu_kick(vcpu);
+		else
+			irq_work_queue(&vcpu->arch.pmu.overflow_work);
+	}
+
+	cpu_pmu->pmu.start(perf_event, PERF_EF_RELOAD);
+}
+
+/**
+ * kvm_pmu_software_increment - do software increment
+ * @vcpu: The vcpu pointer
+ * @val: the value guest writes to PMSWINC register
+ */
+void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
+{
+	kvm_pmu_counter_increment(vcpu, val, ARMV8_PMUV3_PERFCTR_SW_INCR);
+}
+
+/**
+ * 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)
+{
+	int i;
+
+	if (!kvm_vcpu_has_pmu(vcpu))
+		return;
+
+	/* The reset bits don't indicate any state, and shouldn't be saved. */
+	__vcpu_sys_reg(vcpu, PMCR_EL0) = val & ~(ARMV8_PMU_PMCR_C | ARMV8_PMU_PMCR_P);
+
+	if (val & ARMV8_PMU_PMCR_E) {
+		kvm_pmu_enable_counter_mask(vcpu,
+		       __vcpu_sys_reg(vcpu, PMCNTENSET_EL0));
+	} else {
+		kvm_pmu_disable_counter_mask(vcpu,
+		       __vcpu_sys_reg(vcpu, PMCNTENSET_EL0));
+	}
+
+	if (val & ARMV8_PMU_PMCR_C)
+		kvm_pmu_set_counter_value(vcpu, ARMV8_PMU_CYCLE_IDX, 0);
+
+	if (val & ARMV8_PMU_PMCR_P) {
+		unsigned long mask = kvm_pmu_valid_counter_mask(vcpu);
+		mask &= ~BIT(ARMV8_PMU_CYCLE_IDX);
+		for_each_set_bit(i, &mask, 32)
+			kvm_pmu_set_counter_value(vcpu, i, 0);
+	}
+	kvm_vcpu_pmu_restore_guest(vcpu);
+}
+
+static bool kvm_pmu_counter_is_enabled(struct kvm_vcpu *vcpu, u64 select_idx)
+{
+	return (__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) &&
+	       (__vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & BIT(select_idx));
+}
+
+/**
+ * kvm_pmu_create_perf_event - create a perf event for a counter
+ * @vcpu: The vcpu pointer
+ * @select_idx: The number of selected counter
+ */
+static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
+{
+	struct arm_pmu *arm_pmu = vcpu->kvm->arch.arm_pmu;
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+	struct kvm_pmc *pmc = &pmu->pmc[select_idx];
+	struct perf_event *event;
+	struct perf_event_attr attr;
+	u64 eventsel, counter, reg, data;
+
+	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);
+	if (pmc->idx == ARMV8_PMU_CYCLE_IDX)
+		eventsel = ARMV8_PMUV3_PERFCTR_CPU_CYCLES;
+	else
+		eventsel = data & kvm_pmu_event_mask(vcpu->kvm);
+
+	/*
+	 * Neither SW increment nor chained events need to be backed
+	 * by a perf event.
+	 */
+	if (eventsel == ARMV8_PMUV3_PERFCTR_SW_INCR ||
+	    eventsel == ARMV8_PMUV3_PERFCTR_CHAIN)
+		return;
+
+	/*
+	 * If we have a filter in place and that the event isn't allowed, do
+	 * not install a perf event either.
+	 */
+	if (vcpu->kvm->arch.pmu_filter &&
+	    !test_bit(eventsel, vcpu->kvm->arch.pmu_filter))
+		return;
+
+	memset(&attr, 0, sizeof(struct perf_event_attr));
+	attr.type = arm_pmu->pmu.type;
+	attr.size = sizeof(attr);
+	attr.pinned = 1;
+	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 = eventsel;
+
+	counter = kvm_pmu_get_counter_value(vcpu, select_idx);
+
+	/*
+	 * If counting with a 64bit counter, advertise it to the perf
+	 * code, carefully dealing with the initial sample period
+	 * which also depends on the overflow.
+	 */
+	if (kvm_pmu_idx_is_64bit(vcpu, select_idx))
+		attr.config1 |= PERF_ATTR_CFG1_COUNTER_64BIT;
+
+	attr.sample_period = compute_period(vcpu, select_idx, counter);
+
+	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));
+		return;
+	}
+
+	pmc->perf_event = event;
+}
+
+/**
+ * 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
+ * @select_idx: The number of selected counter
+ *
+ * When OS accesses PMXEVTYPER_EL0, that means it wants to set a PMC to count an
+ * event with given hardware event number. Here we call perf_event API to
+ * emulate this action and create a kernel perf event for it.
+ */
+void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
+				    u64 select_idx)
+{
+	u64 reg, mask;
+
+	if (!kvm_vcpu_has_pmu(vcpu))
+		return;
+
+	mask  =  ARMV8_PMU_EVTYPE_MASK;
+	mask &= ~ARMV8_PMU_EVTYPE_EVENT;
+	mask |= kvm_pmu_event_mask(vcpu->kvm);
+
+	reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
+	      ? PMCCFILTR_EL0 : PMEVTYPER0_EL0 + select_idx;
+
+	__vcpu_sys_reg(vcpu, reg) = data & mask;
+
+	kvm_pmu_create_perf_event(vcpu, select_idx);
+}
+
+void kvm_host_pmu_init(struct arm_pmu *pmu)
+{
+	struct arm_pmu_entry *entry;
+
+	if (pmu->pmuver == 0 || pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
+		return;
+
+	mutex_lock(&arm_pmus_lock);
+
+	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		goto out_unlock;
+
+	entry->arm_pmu = pmu;
+	list_add_tail(&entry->entry, &arm_pmus);
+
+	if (list_is_singular(&arm_pmus))
+		static_branch_enable(&kvm_arm_pmu_available);
+
+out_unlock:
+	mutex_unlock(&arm_pmus_lock);
+}
+
+static struct arm_pmu *kvm_pmu_probe_armpmu(void)
+{
+	struct perf_event_attr attr = { };
+	struct perf_event *event;
+	struct arm_pmu *pmu = NULL;
+
+	/*
+	 * Create a dummy event that only counts user cycles. As we'll never
+	 * leave this function with the event being live, it will never
+	 * count anything. But it allows us to probe some of the PMU
+	 * details. Yes, this is terrible.
+	 */
+	attr.type = PERF_TYPE_RAW;
+	attr.size = sizeof(attr);
+	attr.pinned = 1;
+	attr.disabled = 0;
+	attr.exclude_user = 0;
+	attr.exclude_kernel = 1;
+	attr.exclude_hv = 1;
+	attr.exclude_host = 1;
+	attr.config = ARMV8_PMUV3_PERFCTR_CPU_CYCLES;
+	attr.sample_period = GENMASK(63, 0);
+
+	event = perf_event_create_kernel_counter(&attr, -1, current,
+						 kvm_pmu_perf_overflow, &attr);
+
+	if (IS_ERR(event)) {
+		pr_err_once("kvm: pmu event creation failed %ld\n",
+			    PTR_ERR(event));
+		return NULL;
+	}
+
+	if (event->pmu) {
+		pmu = to_arm_pmu(event->pmu);
+		if (pmu->pmuver == 0 ||
+		    pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
+			pmu = NULL;
+	}
+
+	perf_event_disable(event);
+	perf_event_release_kernel(event);
+
+	return pmu;
+}
+
+u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
+{
+	unsigned long *bmap = vcpu->kvm->arch.pmu_filter;
+	u64 val, mask = 0;
+	int base, i, nr_events;
+
+	if (!kvm_vcpu_has_pmu(vcpu))
+		return 0;
+
+	if (!pmceid1) {
+		val = read_sysreg(pmceid0_el0);
+		base = 0;
+	} else {
+		val = read_sysreg(pmceid1_el0);
+		/*
+		 * Don't advertise STALL_SLOT, as PMMIR_EL0 is handled
+		 * as RAZ
+		 */
+		if (vcpu->kvm->arch.arm_pmu->pmuver >= ID_AA64DFR0_EL1_PMUVer_V3P4)
+			val &= ~BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT - 32);
+		base = 32;
+	}
+
+	if (!bmap)
+		return val;
+
+	nr_events = kvm_pmu_event_mask(vcpu->kvm) + 1;
+
+	for (i = 0; i < 32; i += 8) {
+		u64 byte;
+
+		byte = bitmap_get_value8(bmap, base + i);
+		mask |= byte << i;
+		if (nr_events >= (0x4000 + base + 32)) {
+			byte = bitmap_get_value8(bmap, 0x4000 + base + i);
+			mask |= byte << (32 + i);
+		}
+	}
+
+	return val & mask;
+}
+
+int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu)
+{
+	if (!kvm_vcpu_has_pmu(vcpu))
+		return 0;
+
+	if (!vcpu->arch.pmu.created)
+		return -EINVAL;
+
+	/*
+	 * A valid interrupt configuration for the PMU is either to have a
+	 * properly configured interrupt number and using an in-kernel
+	 * irqchip, or to not have an in-kernel GIC and not set an IRQ.
+	 */
+	if (irqchip_in_kernel(vcpu->kvm)) {
+		int irq = vcpu->arch.pmu.irq_num;
+		/*
+		 * If we are using an in-kernel vgic, at this point we know
+		 * the vgic will be initialized, so we can check the PMU irq
+		 * number against the dimensions of the vgic and make sure
+		 * it's valid.
+		 */
+		if (!irq_is_ppi(irq) && !vgic_valid_spi(vcpu->kvm, irq))
+			return -EINVAL;
+	} else if (kvm_arm_pmu_irq_initialized(vcpu)) {
+		   return -EINVAL;
+	}
+
+	/* One-off reload of the PMU on first run */
+	kvm_make_request(KVM_REQ_RELOAD_PMU, vcpu);
+
+	return 0;
+}
+
+static int kvm_arm_pmu_v3_init(struct kvm_vcpu *vcpu)
+{
+	if (irqchip_in_kernel(vcpu->kvm)) {
+		int ret;
+
+		/*
+		 * If using the PMU with an in-kernel virtual GIC
+		 * implementation, we require the GIC to be already
+		 * initialized when initializing the PMU.
+		 */
+		if (!vgic_initialized(vcpu->kvm))
+			return -ENODEV;
+
+		if (!kvm_arm_pmu_irq_initialized(vcpu))
+			return -ENXIO;
+
+		ret = kvm_vgic_set_owner(vcpu, vcpu->arch.pmu.irq_num,
+					 &vcpu->arch.pmu);
+		if (ret)
+			return ret;
+	}
+
+	init_irq_work(&vcpu->arch.pmu.overflow_work,
+		      kvm_pmu_perf_overflow_notify_vcpu);
+
+	vcpu->arch.pmu.created = true;
+	return 0;
+}
+
+/*
+ * For one VM the interrupt type must be same for each vcpu.
+ * As a PPI, the interrupt number is the same for all vcpus,
+ * while as an SPI it must be a separate number per vcpu.
+ */
+static bool pmu_irq_is_valid(struct kvm *kvm, int irq)
+{
+	unsigned long i;
+	struct kvm_vcpu *vcpu;
+
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		if (!kvm_arm_pmu_irq_initialized(vcpu))
+			continue;
+
+		if (irq_is_ppi(irq)) {
+			if (vcpu->arch.pmu.irq_num != irq)
+				return false;
+		} else {
+			if (vcpu->arch.pmu.irq_num == irq)
+				return false;
+		}
+	}
+
+	return true;
+}
+
+static int kvm_arm_pmu_v3_set_pmu(struct kvm_vcpu *vcpu, int pmu_id)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct arm_pmu_entry *entry;
+	struct arm_pmu *arm_pmu;
+	int ret = -ENXIO;
+
+	lockdep_assert_held(&kvm->arch.config_lock);
+	mutex_lock(&arm_pmus_lock);
+
+	list_for_each_entry(entry, &arm_pmus, entry) {
+		arm_pmu = entry->arm_pmu;
+		if (arm_pmu->pmu.type == pmu_id) {
+			if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags) ||
+			    (kvm->arch.pmu_filter && kvm->arch.arm_pmu != arm_pmu)) {
+				ret = -EBUSY;
+				break;
+			}
+
+			kvm->arch.arm_pmu = arm_pmu;
+			cpumask_copy(kvm->arch.supported_cpus, &arm_pmu->supported_cpus);
+			ret = 0;
+			break;
+		}
+	}
+
+	mutex_unlock(&arm_pmus_lock);
+	return ret;
+}
+
+int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+	struct kvm *kvm = vcpu->kvm;
+
+	lockdep_assert_held(&kvm->arch.config_lock);
+
+	if (!kvm_vcpu_has_pmu(vcpu))
+		return -ENODEV;
+
+	if (vcpu->arch.pmu.created)
+		return -EBUSY;
+
+	if (!kvm->arch.arm_pmu) {
+		/* No PMU set, get the default one */
+		kvm->arch.arm_pmu = kvm_pmu_probe_armpmu();
+		if (!kvm->arch.arm_pmu)
+			return -ENODEV;
+	}
+
+	switch (attr->attr) {
+	case KVM_ARM_VCPU_PMU_V3_IRQ: {
+		int __user *uaddr = (int __user *)(long)attr->addr;
+		int irq;
+
+		if (!irqchip_in_kernel(kvm))
+			return -EINVAL;
+
+		if (get_user(irq, uaddr))
+			return -EFAULT;
+
+		/* The PMU overflow interrupt can be a PPI or a valid SPI. */
+		if (!(irq_is_ppi(irq) || irq_is_spi(irq)))
+			return -EINVAL;
+
+		if (!pmu_irq_is_valid(kvm, irq))
+			return -EINVAL;
+
+		if (kvm_arm_pmu_irq_initialized(vcpu))
+			return -EBUSY;
+
+		kvm_debug("Set kvm ARM PMU irq: %d\n", irq);
+		vcpu->arch.pmu.irq_num = irq;
+		return 0;
+	}
+	case KVM_ARM_VCPU_PMU_V3_FILTER: {
+		struct kvm_pmu_event_filter __user *uaddr;
+		struct kvm_pmu_event_filter filter;
+		int nr_events;
+
+		nr_events = kvm_pmu_event_mask(kvm) + 1;
+
+		uaddr = (struct kvm_pmu_event_filter __user *)(long)attr->addr;
+
+		if (copy_from_user(&filter, uaddr, sizeof(filter)))
+			return -EFAULT;
+
+		if (((u32)filter.base_event + filter.nevents) > nr_events ||
+		    (filter.action != KVM_PMU_EVENT_ALLOW &&
+		     filter.action != KVM_PMU_EVENT_DENY))
+			return -EINVAL;
+
+		if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags))
+			return -EBUSY;
+
+		if (!kvm->arch.pmu_filter) {
+			kvm->arch.pmu_filter = bitmap_alloc(nr_events, GFP_KERNEL_ACCOUNT);
+			if (!kvm->arch.pmu_filter)
+				return -ENOMEM;
+
+			/*
+			 * The default depends on the first applied filter.
+			 * If it allows events, the default is to deny.
+			 * Conversely, if the first filter denies a set of
+			 * events, the default is to allow.
+			 */
+			if (filter.action == KVM_PMU_EVENT_ALLOW)
+				bitmap_zero(kvm->arch.pmu_filter, nr_events);
+			else
+				bitmap_fill(kvm->arch.pmu_filter, nr_events);
+		}
+
+		if (filter.action == KVM_PMU_EVENT_ALLOW)
+			bitmap_set(kvm->arch.pmu_filter, filter.base_event, filter.nevents);
+		else
+			bitmap_clear(kvm->arch.pmu_filter, filter.base_event, filter.nevents);
+
+		return 0;
+	}
+	case KVM_ARM_VCPU_PMU_V3_SET_PMU: {
+		int __user *uaddr = (int __user *)(long)attr->addr;
+		int pmu_id;
+
+		if (get_user(pmu_id, uaddr))
+			return -EFAULT;
+
+		return kvm_arm_pmu_v3_set_pmu(vcpu, pmu_id);
+	}
+	case KVM_ARM_VCPU_PMU_V3_INIT:
+		return kvm_arm_pmu_v3_init(vcpu);
+	}
+
+	return -ENXIO;
+}
+
+int kvm_arm_pmu_v3_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+	switch (attr->attr) {
+	case KVM_ARM_VCPU_PMU_V3_IRQ: {
+		int __user *uaddr = (int __user *)(long)attr->addr;
+		int irq;
+
+		if (!irqchip_in_kernel(vcpu->kvm))
+			return -EINVAL;
+
+		if (!kvm_vcpu_has_pmu(vcpu))
+			return -ENODEV;
+
+		if (!kvm_arm_pmu_irq_initialized(vcpu))
+			return -ENXIO;
+
+		irq = vcpu->arch.pmu.irq_num;
+		return put_user(irq, uaddr);
+	}
+	}
+
+	return -ENXIO;
+}
+
+int kvm_arm_pmu_v3_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+	switch (attr->attr) {
+	case KVM_ARM_VCPU_PMU_V3_IRQ:
+	case KVM_ARM_VCPU_PMU_V3_INIT:
+	case KVM_ARM_VCPU_PMU_V3_FILTER:
+	case KVM_ARM_VCPU_PMU_V3_SET_PMU:
+		if (kvm_vcpu_has_pmu(vcpu))
+			return 0;
+	}
+
+	return -ENXIO;
+}