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

Commit c896939f7cff ("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 <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ad40d44..0a0e00d 100644 (file)
--- 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)