1 files changed, 46 insertions, 28 deletions

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index acf4a4e660c0..322ef9cfdc80 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -1337,12 +1337,54 @@ static int __inject_io(struct kvm *kvm, struct kvm_s390_interrupt_info *inti)
 	return 0;
 }
 
-static int __inject_vm(struct kvm *kvm, struct kvm_s390_interrupt_info *inti)
+/*
+ * Find a destination VCPU for a floating irq and kick it.
+ */
+static void __floating_irq_kick(struct kvm *kvm, u64 type)
 {
+	struct kvm_s390_float_interrupt *fi = &kvm->arch.float_int;
 	struct kvm_s390_local_interrupt *li;
+	struct kvm_vcpu *dst_vcpu;
+	int sigcpu, online_vcpus, nr_tries = 0;
+
+	online_vcpus = atomic_read(&kvm->online_vcpus);
+	if (!online_vcpus)
+		return;
+
+	/* find idle VCPUs first, then round robin */
+	sigcpu = find_first_bit(fi->idle_mask, online_vcpus);
+	if (sigcpu == online_vcpus) {
+		do {
+			sigcpu = fi->next_rr_cpu;
+			fi->next_rr_cpu = (fi->next_rr_cpu + 1) % online_vcpus;
+			/* avoid endless loops if all vcpus are stopped */
+			if (nr_tries++ >= online_vcpus)
+				return;
+		} while (is_vcpu_stopped(kvm_get_vcpu(kvm, sigcpu)));
+	}
+	dst_vcpu = kvm_get_vcpu(kvm, sigcpu);
+
+	/* make the VCPU drop out of the SIE, or wake it up if sleeping */
+	li = &dst_vcpu->arch.local_int;
+	spin_lock(&li->lock);
+	switch (type) {
+	case KVM_S390_MCHK:
+		atomic_set_mask(CPUSTAT_STOP_INT, li->cpuflags);
+		break;
+	case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
+		atomic_set_mask(CPUSTAT_IO_INT, li->cpuflags);
+		break;
+	default:
+		atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
+		break;
+	}
+	spin_unlock(&li->lock);
+	kvm_s390_vcpu_wakeup(dst_vcpu);
+}
+
+static int __inject_vm(struct kvm *kvm, struct kvm_s390_interrupt_info *inti)
+{
 	struct kvm_s390_float_interrupt *fi;
-	struct kvm_vcpu *dst_vcpu = NULL;
-	int sigcpu;
 	u64 type = READ_ONCE(inti->type);
 	int rc;
 
@@ -1370,32 +1412,8 @@ static int __inject_vm(struct kvm *kvm, struct kvm_s390_interrupt_info *inti)
 	if (rc)
 		return rc;
 
-	sigcpu = find_first_bit(fi->idle_mask, KVM_MAX_VCPUS);
-	if (sigcpu == KVM_MAX_VCPUS) {
-		do {
-			sigcpu = fi->next_rr_cpu++;
-			if (sigcpu == KVM_MAX_VCPUS)
-				sigcpu = fi->next_rr_cpu = 0;
-		} while (kvm_get_vcpu(kvm, sigcpu) == NULL);
-	}
-	dst_vcpu = kvm_get_vcpu(kvm, sigcpu);
-	li = &dst_vcpu->arch.local_int;
-	spin_lock(&li->lock);
-	switch (type) {
-	case KVM_S390_MCHK:
-		atomic_set_mask(CPUSTAT_STOP_INT, li->cpuflags);
-		break;
-	case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
-		atomic_set_mask(CPUSTAT_IO_INT, li->cpuflags);
-		break;
-	default:
-		atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
-		break;
-	}
-	spin_unlock(&li->lock);
-	kvm_s390_vcpu_wakeup(kvm_get_vcpu(kvm, sigcpu));
+	__floating_irq_kick(kvm, type);
 	return 0;
-
 }
 
 int kvm_s390_inject_vm(struct kvm *kvm,