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KVM: s390: fast path for sca_ext_call_pending

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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 <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
David Hildenbrand 2015-09-23 09:45:50 +02:00 committed by Christian Borntraeger
parent fe0edcb731
commit 2c1bb2be98
1 changed files with 4 additions and 2 deletions
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6
arch/s390/kvm/interrupt.c
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@ -39,6 +39,9 @@ static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id)
{ {
int c, scn; int c, scn;
if (!(atomic_read(&vcpu->arch.sie_block->cpuflags) & CPUSTAT_ECALL_PEND))
return 0;
read_lock(&vcpu->kvm->arch.sca_lock); read_lock(&vcpu->kvm->arch.sca_lock);
if (vcpu->kvm->arch.use_esca) { if (vcpu->kvm->arch.use_esca) {
struct esca_block *sca = vcpu->kvm->arch.sca; 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) if (src_id)
*src_id = scn; *src_id = scn;
return c && atomic_read(&vcpu->arch.sie_block->cpuflags) & return c;
CPUSTAT_ECALL_PEND;
} }
static int sca_inject_ext_call(struct kvm_vcpu *vcpu, int src_id) static int sca_inject_ext_call(struct kvm_vcpu *vcpu, int src_id)