KVM: remove NULL return path for vcpu ids >= KVM_MAX_VCPUS

Commit c896939 ("KVM: use heuristic for fast VCPU lookup by id") added a return path that prevents vcpu ids to exceed KVM_MAX_VCPUS. This is a problem for powerpc where vcpu ids can grow up to 8*KVM_MAX_VCPUS. This patch simply reverses the logic so that we only try fast path if the vcpu id can be tried as an index in kvm->vcpus[]. The slow path is not affected by the change. Reviewed-by: David Hildenbrand <[email protected]> Reviewed-by: Cornelia Huck <[email protected]> Signed-off-by: Greg Kurz <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
lucamilanesio · May 11, 2016 · 9b9e3fc · 9b9e3fc
1 parent bdb4094
commit 9b9e3fc
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
@@ -447,12 +447,13 @@ static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i)
 
 static inline struct kvm_vcpu *kvm_get_vcpu_by_id(struct kvm *kvm, int id)
 {
-	struct kvm_vcpu *vcpu;
+	struct kvm_vcpu *vcpu = NULL;
 	int i;
 
-	if (id < 0 || id >= KVM_MAX_VCPUS)
+	if (id < 0)
 		return NULL;
-	vcpu = kvm_get_vcpu(kvm, id);
+	if (id < KVM_MAX_VCPUS)
+		vcpu = kvm_get_vcpu(kvm, id);
 	if (vcpu && vcpu->vcpu_id == id)
 		return vcpu;
 	kvm_for_each_vcpu(i, vcpu, kvm)