1 files changed, 256 insertions, 0 deletions
diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
new file mode 100644
index 000000000..a243934c5
--- /dev/null
+++ b/arch/arm64/kvm/pmu.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Arm Limited
+ * Author: Andrew Murray <Andrew.Murray@arm.com>
+ */
+#include <linux/kvm_host.h>
+#include <linux/perf_event.h>
+
+static DEFINE_PER_CPU(struct kvm_pmu_events, kvm_pmu_events);
+
+/*
+ * Given the perf event attributes and system type, determine
+ * if we are going to need to switch counters at guest entry/exit.
+ */
+static bool kvm_pmu_switch_needed(struct perf_event_attr *attr)
+{
+	/**
+	 * With VHE the guest kernel runs at EL1 and the host at EL2,
+	 * where user (EL0) is excluded then we have no reason to switch
+	 * counters.
+	 */
+	if (has_vhe() && attr->exclude_user)
+		return false;
+
+	/* Only switch if attributes are different */
+	return (attr->exclude_host != attr->exclude_guest);
+}
+
+struct kvm_pmu_events *kvm_get_pmu_events(void)
+{
+	return this_cpu_ptr(&kvm_pmu_events);
+}
+
+/*
+ * Add events to track that we may want to switch at guest entry/exit
+ * time.
+ */
+void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr)
+{
+	struct kvm_pmu_events *pmu = kvm_get_pmu_events();
+
+	if (!kvm_arm_support_pmu_v3() || !kvm_pmu_switch_needed(attr))
+		return;
+
+	if (!attr->exclude_host)
+		pmu->events_host |= set;
+	if (!attr->exclude_guest)
+		pmu->events_guest |= set;
+}
+
+/*
+ * Stop tracking events
+ */
+void kvm_clr_pmu_events(u32 clr)
+{
+	struct kvm_pmu_events *pmu = kvm_get_pmu_events();
+
+	if (!kvm_arm_support_pmu_v3())
+		return;
+
+	pmu->events_host &= ~clr;
+	pmu->events_guest &= ~clr;
+}
+
+#define PMEVTYPER_READ_CASE(idx)				\
+	case idx:						\
+		return read_sysreg(pmevtyper##idx##_el0)
+
+#define PMEVTYPER_WRITE_CASE(idx)				\
+	case idx:						\
+		write_sysreg(val, pmevtyper##idx##_el0);	\
+		break
+
+#define PMEVTYPER_CASES(readwrite)				\
+	PMEVTYPER_##readwrite##_CASE(0);			\
+	PMEVTYPER_##readwrite##_CASE(1);			\
+	PMEVTYPER_##readwrite##_CASE(2);			\
+	PMEVTYPER_##readwrite##_CASE(3);			\
+	PMEVTYPER_##readwrite##_CASE(4);			\
+	PMEVTYPER_##readwrite##_CASE(5);			\
+	PMEVTYPER_##readwrite##_CASE(6);			\
+	PMEVTYPER_##readwrite##_CASE(7);			\
+	PMEVTYPER_##readwrite##_CASE(8);			\
+	PMEVTYPER_##readwrite##_CASE(9);			\
+	PMEVTYPER_##readwrite##_CASE(10);			\
+	PMEVTYPER_##readwrite##_CASE(11);			\
+	PMEVTYPER_##readwrite##_CASE(12);			\
+	PMEVTYPER_##readwrite##_CASE(13);			\
+	PMEVTYPER_##readwrite##_CASE(14);			\
+	PMEVTYPER_##readwrite##_CASE(15);			\
+	PMEVTYPER_##readwrite##_CASE(16);			\
+	PMEVTYPER_##readwrite##_CASE(17);			\
+	PMEVTYPER_##readwrite##_CASE(18);			\
+	PMEVTYPER_##readwrite##_CASE(19);			\
+	PMEVTYPER_##readwrite##_CASE(20);			\
+	PMEVTYPER_##readwrite##_CASE(21);			\
+	PMEVTYPER_##readwrite##_CASE(22);			\
+	PMEVTYPER_##readwrite##_CASE(23);			\
+	PMEVTYPER_##readwrite##_CASE(24);			\
+	PMEVTYPER_##readwrite##_CASE(25);			\
+	PMEVTYPER_##readwrite##_CASE(26);			\
+	PMEVTYPER_##readwrite##_CASE(27);			\
+	PMEVTYPER_##readwrite##_CASE(28);			\
+	PMEVTYPER_##readwrite##_CASE(29);			\
+	PMEVTYPER_##readwrite##_CASE(30)
+
+/*
+ * Read a value direct from PMEVTYPER<idx> where idx is 0-30
+ * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31).
+ */
+static u64 kvm_vcpu_pmu_read_evtype_direct(int idx)
+{
+	switch (idx) {
+	PMEVTYPER_CASES(READ);
+	case ARMV8_PMU_CYCLE_IDX:
+		return read_sysreg(pmccfiltr_el0);
+	default:
+		WARN_ON(1);
+	}
+
+	return 0;
+}
+
+/*
+ * Write a value direct to PMEVTYPER<idx> where idx is 0-30
+ * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31).
+ */
+static void kvm_vcpu_pmu_write_evtype_direct(int idx, u32 val)
+{
+	switch (idx) {
+	PMEVTYPER_CASES(WRITE);
+	case ARMV8_PMU_CYCLE_IDX:
+		write_sysreg(val, pmccfiltr_el0);
+		break;
+	default:
+		WARN_ON(1);
+	}
+}
+
+/*
+ * Modify ARMv8 PMU events to include EL0 counting
+ */
+static void kvm_vcpu_pmu_enable_el0(unsigned long events)
+{
+	u64 typer;
+	u32 counter;
+
+	for_each_set_bit(counter, &events, 32) {
+		typer = kvm_vcpu_pmu_read_evtype_direct(counter);
+		typer &= ~ARMV8_PMU_EXCLUDE_EL0;
+		kvm_vcpu_pmu_write_evtype_direct(counter, typer);
+	}
+}
+
+/*
+ * Modify ARMv8 PMU events to exclude EL0 counting
+ */
+static void kvm_vcpu_pmu_disable_el0(unsigned long events)
+{
+	u64 typer;
+	u32 counter;
+
+	for_each_set_bit(counter, &events, 32) {
+		typer = kvm_vcpu_pmu_read_evtype_direct(counter);
+		typer |= ARMV8_PMU_EXCLUDE_EL0;
+		kvm_vcpu_pmu_write_evtype_direct(counter, typer);
+	}
+}
+
+/*
+ * On VHE ensure that only guest events have EL0 counting enabled.
+ * This is called from both vcpu_{load,put} and the sysreg handling.
+ * Since the latter is preemptible, special care must be taken to
+ * disable preemption.
+ */
+void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu)
+{
+	struct kvm_pmu_events *pmu;
+	u32 events_guest, events_host;
+
+	if (!kvm_arm_support_pmu_v3() || !has_vhe())
+		return;
+
+	preempt_disable();
+	pmu = kvm_get_pmu_events();
+	events_guest = pmu->events_guest;
+	events_host = pmu->events_host;
+
+	kvm_vcpu_pmu_enable_el0(events_guest);
+	kvm_vcpu_pmu_disable_el0(events_host);
+	preempt_enable();
+}
+
+/*
+ * On VHE ensure that only host events have EL0 counting enabled
+ */
+void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu)
+{
+	struct kvm_pmu_events *pmu;
+	u32 events_guest, events_host;
+
+	if (!kvm_arm_support_pmu_v3() || !has_vhe())
+		return;
+
+	pmu = kvm_get_pmu_events();
+	events_guest = pmu->events_guest;
+	events_host = pmu->events_host;
+
+	kvm_vcpu_pmu_enable_el0(events_host);
+	kvm_vcpu_pmu_disable_el0(events_guest);
+}
+
+/*
+ * With VHE, keep track of the PMUSERENR_EL0 value for the host EL0 on the pCPU
+ * where PMUSERENR_EL0 for the guest is loaded, since PMUSERENR_EL0 is switched
+ * to the value for the guest on vcpu_load().  The value for the host EL0
+ * will be restored on vcpu_put(), before returning to userspace.
+ * This isn't necessary for nVHE, as the register is context switched for
+ * every guest enter/exit.
+ *
+ * Return true if KVM takes care of the register. Otherwise return false.
+ */
+bool kvm_set_pmuserenr(u64 val)
+{
+	struct kvm_cpu_context *hctxt;
+	struct kvm_vcpu *vcpu;
+
+	if (!kvm_arm_support_pmu_v3() || !has_vhe())
+		return false;
+
+	vcpu = kvm_get_running_vcpu();
+	if (!vcpu || !vcpu_get_flag(vcpu, PMUSERENR_ON_CPU))
+		return false;
+
+	hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
+	ctxt_sys_reg(hctxt, PMUSERENR_EL0) = val;
+	return true;
+}
+
+/*
+ * If we interrupted the guest to update the host PMU context, make
+ * sure we re-apply the guest EL0 state.
+ */
+void kvm_vcpu_pmu_resync_el0(void)
+{
+	struct kvm_vcpu *vcpu;
+
+	if (!has_vhe() || !in_interrupt())
+		return;
+
+	vcpu = kvm_get_running_vcpu();
+	if (!vcpu)
+		return;
+
+	kvm_make_request(KVM_REQ_RESYNC_PMU_EL0, vcpu);
+}