[PATCH v2 21/23] KVM: arm64: Inject recorded guest interrupts

[Colton Lewis <coltonlewis@google.com>]

When we re-enter the VM after handling a PMU interrupt, calculate
whether it was any of the guest counters that overflowed and inject an
interrupt into the guest if so.

Signed-off-by: Colton Lewis <coltonlewis@google.com>
---
 arch/arm64/include/asm/kvm_pmu.h |  2 ++
 arch/arm64/kvm/pmu-emul.c        |  4 ++--
 arch/arm64/kvm/pmu-part.c        | 24 ++++++++++++++++++++++--
 arch/arm64/kvm/pmu.c             |  7 ++++++-
 4 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_pmu.h b/arch/arm64/include/asm/kvm_pmu.h
index e1c8d8fc27bd..1e632373ba38 100644
--- a/arch/arm64/include/asm/kvm_pmu.h
+++ b/arch/arm64/include/asm/kvm_pmu.h
@@ -84,6 +84,8 @@ void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_resync_el0(void);
 void kvm_host_pmu_init(struct arm_pmu *pmu);
+bool kvm_pmu_emul_overflow_status(struct kvm_vcpu *vcpu);
+bool kvm_pmu_part_overflow_status(struct kvm_vcpu *vcpu);
 
 #define kvm_vcpu_has_pmu(vcpu)					\
 	(vcpu_has_feature(vcpu, KVM_ARM_VCPU_PMU_V3))
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index a6452d10fc1e..926aeda51b9e 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -268,7 +268,7 @@ void kvm_pmu_reprogram_counter_mask(struct kvm_vcpu *vcpu, u64 val)
  * counter where the values of the global enable control, PMOVSSET_EL0[n], and
  * PMINTENSET_EL1[n] are all 1.
  */
-bool kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
+bool kvm_pmu_emul_overflow_status(struct kvm_vcpu *vcpu)
 {
 	u64 reg = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
 
@@ -405,7 +405,7 @@ static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
 		kvm_pmu_counter_increment(vcpu, BIT(idx + 1),
 					  ARMV8_PMUV3_PERFCTR_CHAIN);
 
-	if (kvm_pmu_overflow_status(vcpu)) {
+	if (kvm_pmu_emul_overflow_status(vcpu)) {
 		kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 
 		if (!in_nmi())
diff --git a/arch/arm64/kvm/pmu-part.c b/arch/arm64/kvm/pmu-part.c
index 8c35447ef103..2c347e7a26d8 100644
--- a/arch/arm64/kvm/pmu-part.c
+++ b/arch/arm64/kvm/pmu-part.c
@@ -260,7 +260,7 @@ void kvm_pmu_load(struct kvm_vcpu *vcpu)
 	write_pmcr(val);
 
 	/*
-	 * Loading these registers is tricky because of
+	 * Loading these registers is more intricate because of
 	 * 1. Applying only the bits for guest counters (indicated by mask)
 	 * 2. Setting and clearing are different registers
 	 */
@@ -334,5 +334,25 @@ void kvm_pmu_handle_guest_irq(u64 govf)
 	if (!vcpu)
 		return;
 
-	__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= govf;
+	__vcpu_assign_sys_reg(vcpu, PMOVSSET_EL0, govf);
+}
+
+/**
+ * kvm_pmu_part_overflow_status() - Determine if any guest counters have overflowed
+ * @vcpu: Ponter to struct kvm_vcpu
+ *
+ * Determine if any guest counters have overflowed and therefore an
+ * IRQ needs to be injected into the guest.
+ *
+ * Return: True if there was an overflow, false otherwise
+ */
+bool kvm_pmu_part_overflow_status(struct kvm_vcpu *vcpu)
+{
+	struct arm_pmu *pmu = vcpu->kvm->arch.arm_pmu;
+	u64 mask = kvm_pmu_guest_counter_mask(pmu);
+	u64 pmovs = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
+	u64 pmint = read_pmintenset();
+	u64 pmcr = read_pmcr();
+
+	return (pmcr & ARMV8_PMU_PMCR_E) && (mask & pmovs & pmint);
 }
diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
index 5f0847dc7d53..65b380debc33 100644
--- a/arch/arm64/kvm/pmu.c
+++ b/arch/arm64/kvm/pmu.c
@@ -407,7 +407,11 @@ static void kvm_pmu_update_state(struct kvm_vcpu *vcpu)
 	struct kvm_pmu *pmu = &vcpu->arch.pmu;
 	bool overflow;
 
-	overflow = kvm_pmu_overflow_status(vcpu);
+	if (kvm_vcpu_pmu_is_partitioned(vcpu))
+		overflow = kvm_pmu_part_overflow_status(vcpu);
+	else
+		overflow = kvm_pmu_emul_overflow_status(vcpu);
+
 	if (pmu->irq_level == overflow)
 		return;
 
@@ -683,6 +687,7 @@ int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 			return -EBUSY;
 
 		kvm_debug("Set kvm ARM PMU irq: %d\n", irq);
+
 		vcpu->arch.pmu.irq_num = irq;
 		return 0;
 	}
-- 
2.50.0.714.g196bf9f422-goog