KVM: use jump label to optimize checking for in kernel local apic presence
Usually all vcpus have local apic pointer initialized, so the check may
be completely skipped.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 29fa18d..8ebf65c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6152,6 +6152,8 @@
return irqchip_in_kernel(vcpu->kvm) == (vcpu->arch.apic != NULL);
}
+struct static_key kvm_no_apic_vcpu __read_mostly;
+
int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
{
struct page *page;
@@ -6184,7 +6186,8 @@
r = kvm_create_lapic(vcpu);
if (r < 0)
goto fail_mmu_destroy;
- }
+ } else
+ static_key_slow_inc(&kvm_no_apic_vcpu);
vcpu->arch.mce_banks = kzalloc(KVM_MAX_MCE_BANKS * sizeof(u64) * 4,
GFP_KERNEL);
@@ -6224,6 +6227,8 @@
kvm_mmu_destroy(vcpu);
srcu_read_unlock(&vcpu->kvm->srcu, idx);
free_page((unsigned long)vcpu->arch.pio_data);
+ if (!irqchip_in_kernel(vcpu->kvm))
+ static_key_slow_dec(&kvm_no_apic_vcpu);
}
int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)