From 2c1bb2be986c56848ce92ba41ba32fc62ab3165f Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Wed, 23 Sep 2015 09:45:50 +0200 Subject: [PATCH] KVM: s390: fast path for sca_ext_call_pending If CPUSTAT_ECALL_PEND isn't set, we can't have an external call pending, so we can directly avoid taking the lock. Acked-by: Christian Borntraeger Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- arch/s390/kvm/interrupt.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 831c9ac728ec..62ec925aa196 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -39,6 +39,9 @@ static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id) { int c, scn; + if (!(atomic_read(&vcpu->arch.sie_block->cpuflags) & CPUSTAT_ECALL_PEND)) + return 0; + read_lock(&vcpu->kvm->arch.sca_lock); if (vcpu->kvm->arch.use_esca) { struct esca_block *sca = vcpu->kvm->arch.sca; @@ -60,8 +63,7 @@ static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id) if (src_id) *src_id = scn; - return c && atomic_read(&vcpu->arch.sie_block->cpuflags) & - CPUSTAT_ECALL_PEND; + return c; } static int sca_inject_ext_call(struct kvm_vcpu *vcpu, int src_id) -- 2.11.0