kvm: x86: vmx: NULL out hwapic_isr_update() in case of !enable_apicv
In most cases calling hwapic_isr_update(), we always check if
kvm_apic_vid_enabled() == 1, but actually,
kvm_apic_vid_enabled()
-> kvm_x86_ops->vm_has_apicv()
-> vmx_vm_has_apicv() or '0' in svm case
-> return enable_apicv && irqchip_in_kernel(kvm)
So its a little cost to recall vmx_vm_has_apicv() inside
hwapic_isr_update(), here just NULL out hwapic_isr_update() in
case of !enable_apicv inside hardware_setup() then make all
related stuffs follow this. Note we don't check this under that
condition of irqchip_in_kernel() since we should make sure
definitely any caller don't work without in-kernel irqchip.
Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 4f0c0b9..fe8bae5 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -402,7 +402,7 @@
* because the processor can modify ISR under the hood. Instead
* just set SVI.
*/
- if (unlikely(kvm_apic_vid_enabled(vcpu->kvm)))
+ if (unlikely(kvm_x86_ops->hwapic_isr_update))
kvm_x86_ops->hwapic_isr_update(vcpu->kvm, vec);
else {
++apic->isr_count;
@@ -450,7 +450,7 @@
* on the other hand isr_count and highest_isr_cache are unused
* and must be left alone.
*/
- if (unlikely(kvm_apic_vid_enabled(vcpu->kvm)))
+ if (unlikely(kvm_x86_ops->hwapic_isr_update))
kvm_x86_ops->hwapic_isr_update(vcpu->kvm,
apic_find_highest_isr(apic));
else {
@@ -1742,7 +1742,9 @@
if (kvm_x86_ops->hwapic_irr_update)
kvm_x86_ops->hwapic_irr_update(vcpu,
apic_find_highest_irr(apic));
- kvm_x86_ops->hwapic_isr_update(vcpu->kvm, apic_find_highest_isr(apic));
+ if (unlikely(kvm_x86_ops->hwapic_isr_update))
+ kvm_x86_ops->hwapic_isr_update(vcpu->kvm,
+ apic_find_highest_isr(apic));
kvm_make_request(KVM_REQ_EVENT, vcpu);
kvm_rtc_eoi_tracking_restore_one(vcpu);
}
