[PATCH v2 4/5] KVM: arm/arm64: Report PMU overflow interrupts to userspace irqchip

Christoffer Dall
2017-02-03T14:56:54Z

From: Christoffer Dall <christoffer.dall@linaro.org>

When not using an in-kernel VGIC, but instead emulating an interrupt
controller in userspace, we should report the PMU overflow status to
that userspace interrupt controller using the KVM_CAP_ARM_USER_IRQ
feature.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
arch/arm/kvm/arm.c | 9 ++++++---
include/kvm/arm_pmu.h | 7 +++++++
virt/kvm/arm/pmu.c | 42 ++++++++++++++++++++++++++++++++++++++----
3 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 505f928..92f38f6 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -628,11 +628,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)

/*
* If we have a singal pending, or need to notify a userspace
- * irqchip about timer level changes, then we exit (and update
- * the timer level state in kvm_timer_update_run below).
+ * irqchip about timer or PMU level changes, then we exit (and
+ * update the timer level state in kvm_timer_update_run
+ * below).
*/
if (signal_pending(current) ||
- kvm_timer_should_notify_user(vcpu)) {
+ kvm_timer_should_notify_user(vcpu) ||
+ kvm_pmu_should_notify_user(vcpu)) {
ret = -EINTR;
run->exit_reason = KVM_EXIT_INTR;
}
@@ -706,6 +708,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)

/* Tell userspace about in-kernel device output levels */
kvm_timer_update_run(vcpu);
+ kvm_pmu_update_run(vcpu);

if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 92e7e97..1ab4633 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -50,6 +50,8 @@ void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val);
void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val);
void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu);
void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu);
+bool kvm_pmu_should_notify_user(struct kvm_vcpu *vcpu);
+void kvm_pmu_update_run(struct kvm_vcpu *vcpu);
void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val);
void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val);
void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
@@ -85,6 +87,11 @@ static inline void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val) {}
static inline void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val) {}
static inline void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu) {}
static inline void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu) {}
+static inline bool kvm_pmu_should_notify_user(struct kvm_vcpu *vcpu)
+{
+ return false;
+}
+static inline void kvm_pmu_update_run(struct kvm_vcpu *vcpu) {}
static inline void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val) {}
static inline void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val) {}
static inline void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu,
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 69ccce3..51218be 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -230,13 +230,47 @@ static void kvm_pmu_update_state(struct kvm_vcpu *vcpu)
return;

overflow = !!kvm_pmu_overflow_status(vcpu);
- if (pmu->irq_level != overflow) {
- pmu->irq_level = overflow;
- kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
- pmu->irq_num, overflow);
+ if (pmu->irq_level == overflow)
+ return;
+
+ pmu->irq_level = overflow;
+
+ if (likely(irqchip_in_kernel(vcpu->kvm))) {
+ int ret;
+ ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
+ pmu->irq_num, overflow);
+ 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;
+
+ if (likely(irqchip_in_kernel(vcpu->kvm)))
+ return;
+
+ /* 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
--
2.9.0