From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
When calling perf_event_create_kernel_counter to create perf_event,
assign a overflow handler. Then when perf event overflows, call
kvm_vcpu_kick() to sync the interrupt.
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
---
arch/arm/kvm/arm.c | 2 ++
include/kvm/arm_pmu.h | 2 ++
virt/kvm/arm/pmu.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 55 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index e06fd29..cd696ef 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -28,6 +28,7 @@
#include <linux/sched.h>
#include <linux/kvm.h>
#include <trace/events/kvm.h>
+#include <kvm/arm_pmu.h>
#define CREATE_TRACE_POINTS
#include "trace.h"
@@ -569,6 +570,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
* non-preemptible context.
*/
preempt_disable();
+ kvm_pmu_flush_hwstate(vcpu);
kvm_timer_flush_hwstate(vcpu);
kvm_vgic_flush_hwstate(vcpu);
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index a131f76..c4041008 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -38,6 +38,7 @@ struct kvm_pmu {
};
#ifdef CONFIG_KVM_ARM_PMU
+void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu);
u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u32 select_idx);
void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u32 val);
void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u32 val, bool all_enable);
@@ -48,6 +49,7 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u32 data,
u32 select_idx);
void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u32 val);
#else
+void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu) {}
u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u32 select_idx)
{
return 0;
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 9b9c706..ff182d6 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -21,6 +21,7 @@
#include <linux/perf_event.h>
#include <asm/kvm_emulate.h>
#include <kvm/arm_pmu.h>
+#include <kvm/arm_vgic.h>
/**
* kvm_pmu_get_counter_value - get PMU counter value
@@ -90,6 +91,54 @@ static void kvm_pmu_stop_counter(struct kvm_pmc *pmc)
}
/**
+ * kvm_pmu_flush_hwstate - flush pmu state to cpu
+ * @vcpu: The vcpu pointer
+ *
+ * Inject virtual PMU IRQ if IRQ is pending for this cpu.
+ */
+void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu)
+{
+ struct kvm_pmu *pmu = &vcpu->arch.pmu;
+ u32 overflow;
+
+ if (pmu->irq_num == -1)
+ return;
+
+ if (!vcpu_mode_is_32bit(vcpu)) {
+ if (!(vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMCR_E))
+ return;
+
+ overflow = vcpu_sys_reg(vcpu, PMCNTENSET_EL0)
+ & vcpu_sys_reg(vcpu, PMINTENSET_EL1)
+ & vcpu_sys_reg(vcpu, PMOVSSET_EL0);
+ } else {
+ if (!(vcpu_cp15(vcpu, c9_PMCR) & ARMV8_PMCR_E))
+ return;
+
+ overflow = vcpu_cp15(vcpu, c9_PMCNTENSET)
+ & vcpu_cp15(vcpu, c9_PMINTENSET)
+ & vcpu_cp15(vcpu, c9_PMOVSSET);
+ }
+
+ kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, pmu->irq_num,
+ overflow ? 1 : 0);
+}
+
+/**
+ * When perf event overflows, call kvm_pmu_overflow_set to set overflow status.
+ */
+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 kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
+ int idx = pmc->idx;
+
+ kvm_pmu_overflow_set(vcpu, BIT(idx));
+}
+
+/**
* kvm_pmu_enable_counter - enable selected PMU counter
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCNTENSET register
@@ -341,7 +390,8 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u32 data,
/* 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);
+ event = perf_event_create_kernel_counter(&attr, -1, current,
+ kvm_pmu_perf_overflow, pmc);
if (IS_ERR(event)) {
printk_once("kvm: pmu event creation failed %ld\n",
PTR_ERR(event));
--
2.0.4
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