[PATCH v7 15/15] KVM: s390: test for non NULL gisa origin in pending_irqs()

[Michael Mueller]

Assure a GISA is in use before accessing the IPM to avoid
a NULL pointer de-referencing issue.

Reported-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
---
 arch/s390/kvm/interrupt.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index d322400ca587..660ec87b6e60 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -329,9 +329,13 @@ static inline unsigned long pending_irqs_no_gisa(struct kvm_vcpu *vcpu)
 
 static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu)
 {
-	return pending_irqs_no_gisa(vcpu) |
-		gisa_get_ipm(vcpu->kvm->arch.gisa_int.origin) <<
-			IRQ_PEND_IO_ISC_7;
+	struct kvm_s390_gisa_interrupt *gi = &vcpu->kvm->arch.gisa_int;
+	unsigned long pending_mask;
+
+	pending_mask = pending_irqs_no_gisa(vcpu);
+	if (gi->origin)
+		pending_mask |= gisa_get_ipm(gi->origin) << IRQ_PEND_IO_ISC_7;
+	return pending_mask;
 }
 
 static inline int isc_to_irq_type(unsigned long isc)
-- 
2.13.4