From fe2a357526710a65c5e4131883bd612b5ff5170c Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Thu, 16 Apr 2015 16:58:22 +0200
Subject: [PATCH] KVM: s390: optimize round trip time in request handling
The fast path for a sie exit is that no kvm reqest is pending.
Make an early check to skip all single bit checks.
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
arch/s390/kvm/kvm-s390.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 8cd8e7b288c5d..f5282e62f87f4 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1720,6 +1720,8 @@ static bool ibs_enabled(struct kvm_vcpu *vcpu)
static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu)
{
+ if (!vcpu->requests)
+ return 0;
retry:
s390_vcpu_unblock(vcpu);
/*
--
2.39.5