KVM: x86: fix *NULL on invalid low-prio irq

Smatch noticed a NULL dereference in kvm_intr_is_single_vcpu_fast that
happens if VM already warned about invalid lowest-priority interrupt.

Create a function for common code while fixing it.

Fixes: 6228a0da8057 ("KVM: x86: Add lowest-priority support for vt-d posted-interrupts")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 1482a581a83c659a3a40dd9ca2b224ea98cd3d04..cf74404230cac48f462115dd5389e4bef7695438 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -685,6 +685,15 @@ int kvm_vector_to_index(u32 vector, u32 dest_vcpus,
        return idx;
 }
 
+static void kvm_apic_disabled_lapic_found(struct kvm *kvm)
+{
+       if (!kvm->arch.disabled_lapic_found) {
+               kvm->arch.disabled_lapic_found = true;
+               printk(KERN_INFO
+                      "Disabled LAPIC found during irq injection\n");
+       }
+}
+
 bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
                struct kvm_lapic_irq *irq, int *r, unsigned long *dest_map)
 {
@@ -763,15 +772,8 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
                        idx = kvm_vector_to_index(irq->vector,
                                dest_vcpus, &bitmap, 16);
 
-                       /*
-                        * We may find a hardware disabled LAPIC here, if that
-                        * is the case, print out a error message once for each
-                        * guest and return.
-                        */
-                       if (!dst[idx] && !kvm->arch.disabled_lapic_found) {
-                               kvm->arch.disabled_lapic_found = true;
-                               printk(KERN_INFO
-                                       "Disabled LAPIC found during irq injection\n");
+                       if (!dst[idx]) {
+                               kvm_apic_disabled_lapic_found(kvm);
                                goto out;
                        }
 
@@ -859,16 +861,9 @@ bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
                        idx = kvm_vector_to_index(irq->vector, dest_vcpus,
                                                  &bitmap, 16);
 
-                       /*
-                        * We may find a hardware disabled LAPIC here, if that
-                        * is the case, print out a error message once for each
-                        * guest and return
-                        */
                        dst = map->logical_map[cid][idx];
-                       if (!dst && !kvm->arch.disabled_lapic_found) {
-                               kvm->arch.disabled_lapic_found = true;
-                               printk(KERN_INFO
-                                       "Disabled LAPIC found during irq injection\n");
+                       if (!dst) {
+                               kvm_apic_disabled_lapic_found(kvm);
                                goto out;
                        }