KVM: x86: optimize some accesses to LVTT and SPIV

We mirror a subset of these registers in separate variables.
Using them directly should be faster.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 35d83dc..d4365f2 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -121,11 +121,11 @@
 
 extern struct static_key_deferred apic_sw_disabled;
 
-static inline int kvm_apic_sw_enabled(struct kvm_lapic *apic)
+static inline bool kvm_apic_sw_enabled(struct kvm_lapic *apic)
 {
 	if (static_key_false(&apic_sw_disabled.key))
-		return kvm_apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_APIC_ENABLED;
-	return APIC_SPIV_APIC_ENABLED;
+		return apic->sw_enabled;
+	return true;
 }
 
 static inline bool kvm_apic_present(struct kvm_vcpu *vcpu)