KVM: s390: Do not yield when target is already running

If the target is already running we do not need to yield. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
mariux64 · Oct 10, 2019 · c7b7de6 · c7b7de6
1 parent 8474e5c
commit c7b7de6
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
@@ -168,6 +168,10 @@ static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
 	if (!tcpu)
 		goto no_yield;
 
+	/* target already running */
+	if (READ_ONCE(tcpu->cpu) >= 0)
+		goto no_yield;
+
 	if (kvm_vcpu_yield_to(tcpu) <= 0)
 		goto no_yield;