From c7b7de63124645089ccf9900b9e5ea08059ccae0 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Fri, 15 Feb 2019 13:47:20 +0100 Subject: [PATCH] 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 Reviewed-by: David Hildenbrand Reviewed-by: Cornelia Huck --- arch/s390/kvm/diag.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c index 609c55d..3fb54ec 100644 --- 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; -- 2.7.4