@@ -18,6 +18,7 @@
#define ARMV8_MAX_COUNTERS 32
#define ARMV8_COUNTER_MASK (ARMV8_MAX_COUNTERS - 1)
+#define ARMV8_CYCLE_IDX (ARMV8_MAX_COUNTERS - 1)
/*
* Per-CPU PMCR: config reg
@@ -28,6 +29,8 @@
#define ARMV8_PMCR_D (1 << 3) /* CCNT counts every 64th cpu cycle */
#define ARMV8_PMCR_X (1 << 4) /* Export to ETM */
#define ARMV8_PMCR_DP (1 << 5) /* Disable CCNT if non-invasive debug*/
+/* Determines which PMCCNTR_EL0 bit generates an overflow */
+#define ARMV8_PMCR_LC (1 << 6)
#define ARMV8_PMCR_N_SHIFT 11 /* Number of counters supported */
#define ARMV8_PMCR_N_MASK 0x1f
#define ARMV8_PMCR_MASK 0x3f /* Mask for writable bits */
@@ -27,3 +27,4 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic-v3.o
kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic-v3-emul.o
kvm-$(CONFIG_KVM_ARM_HOST) += vgic-v3-switch.o
kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/arch_timer.o
+kvm-$(CONFIG_KVM_ARM_PMU) += $(KVM)/arm/pmu.o
@@ -34,9 +34,20 @@ struct kvm_pmu {
int irq_num;
struct kvm_pmc pmc[ARMV8_MAX_COUNTERS];
};
+
+u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx);
+void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
+ u64 select_idx);
#else
struct kvm_pmu {
};
+
+u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
+{
+ return 0;
+}
+void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
+ u64 select_idx) {}
#endif
#endif
new file mode 100644
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2015 Linaro Ltd.
+ * Author: Shannon Zhao <shannon.zhao@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/cpu.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/perf_event.h>
+#include <asm/kvm_emulate.h>
+#include <kvm/arm_pmu.h>
+
+/**
+ * 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];
+
+ reg = (select_idx == ARMV8_CYCLE_IDX)
+ ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_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);
+
+ return counter & pmc->bitmask;
+}
+
+static inline bool kvm_pmu_counter_is_enabled(struct kvm_vcpu *vcpu,
+ u64 select_idx)
+{
+ return (vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMCR_E) &&
+ (vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & BIT(select_idx));
+}
+
+/**
+ * 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;
+
+ if (pmc->perf_event) {
+ counter = kvm_pmu_get_counter_value(vcpu, pmc->idx);
+ reg = (pmc->idx == ARMV8_CYCLE_IDX)
+ ? PMCCNTR_EL0 : PMEVCNTR0_EL0 + pmc->idx;
+ vcpu_sys_reg(vcpu, reg) = counter;
+ perf_event_release_kernel(pmc->perf_event);
+ pmc->perf_event = NULL;
+ }
+}
+
+/**
+ * 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)
+{
+ 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;
+
+ kvm_pmu_stop_counter(vcpu, pmc);
+ eventsel = data & ARMV8_EVTYPE_EVENT;
+
+ 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.exclude_user = data & ARMV8_EXCLUDE_EL0 ? 1 : 0;
+ attr.exclude_kernel = data & ARMV8_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);
+ /* The initial sample period (overflow count) of an event. */
+ attr.sample_period = (-counter) & pmc->bitmask;
+
+ event = perf_event_create_kernel_counter(&attr, -1, current, NULL, pmc);
+ if (IS_ERR(event)) {
+ printk_once("kvm: pmu event creation failed %ld\n",
+ PTR_ERR(event));
+ return;
+ }
+
+ pmc->perf_event = event;
+}