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Commit f8c1ea10 authored by Gleb Natapov's avatar Gleb Natapov Committed by Avi Kivity
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KVM: use jump label to optimize checking for SW enabled apic in spurious interrupt register 



Usually all APICs are SW enabled so the check can be optimized out.

Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent c5cc421b

arch/x86/kvm/lapic.c

+31 −8
Original line number Diff line number Diff line
@@ -127,9 +127,24 @@ static inline int apic_hw_enabled(struct kvm_lapic *apic) 
	return MSR_IA32_APICBASE_ENABLE;

}



struct static_key_deferred apic_sw_disabled __read_mostly;



static inline void apic_set_spiv(struct kvm_lapic *apic, u32 val)

{

	if ((apic_get_reg(apic, APIC_SPIV) ^ val) & APIC_SPIV_APIC_ENABLED) {

		if (val & APIC_SPIV_APIC_ENABLED)

			static_key_slow_dec_deferred(&apic_sw_disabled);

		else

			static_key_slow_inc(&apic_sw_disabled.key);

	}

	apic_set_reg(apic, APIC_SPIV, val);

}



static inline int apic_sw_enabled(struct kvm_lapic *apic)

{

	if (static_key_false(&apic_sw_disabled.key))

		return apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_APIC_ENABLED;

	return APIC_SPIV_APIC_ENABLED;

}



static inline int apic_enabled(struct kvm_lapic *apic)
@@ -918,7 +933,7 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val) 
		u32 mask = 0x3ff;

		if (apic_get_reg(apic, APIC_LVR) & APIC_LVR_DIRECTED_EOI)

			mask |= APIC_SPIV_DIRECTED_EOI;

		apic_set_reg(apic, APIC_SPIV, val & mask);

		apic_set_spiv(apic, val & mask);

		if (!(val & APIC_SPIV_APIC_ENABLED)) {

			int i;

			u32 lvt_val;
@@ -1055,18 +1070,23 @@ EXPORT_SYMBOL_GPL(kvm_lapic_set_eoi); 


void kvm_free_lapic(struct kvm_vcpu *vcpu)

{

	struct kvm_lapic *apic = vcpu->arch.apic;



	if (!vcpu->arch.apic)

		return;



	hrtimer_cancel(&vcpu->arch.apic->lapic_timer.timer);

	hrtimer_cancel(&apic->lapic_timer.timer);



	if (!(vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE))

		static_key_slow_dec_deferred(&apic_hw_disabled);



	if (vcpu->arch.apic->regs)

		free_page((unsigned long)vcpu->arch.apic->regs);

	if (!(apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_APIC_ENABLED))

		static_key_slow_dec_deferred(&apic_sw_disabled);



	kfree(vcpu->arch.apic);

	if (apic->regs)

		free_page((unsigned long)apic->regs);



	kfree(apic);

}



/*
@@ -1182,7 +1202,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu) 
		     SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));



	apic_set_reg(apic, APIC_DFR, 0xffffffffU);

	apic_set_reg(apic, APIC_SPIV, 0xff);

	apic_set_spiv(apic, 0xff);

	apic_set_reg(apic, APIC_TASKPRI, 0);

	apic_set_reg(apic, APIC_LDR, 0);

	apic_set_reg(apic, APIC_ESR, 0);
@@ -1335,6 +1355,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu) 
	kvm_lapic_set_base(vcpu,

			APIC_DEFAULT_PHYS_BASE | MSR_IA32_APICBASE_ENABLE);



	static_key_slow_inc(&apic_sw_disabled.key); /* sw disabled at reset */

	kvm_lapic_reset(vcpu);

	kvm_iodevice_init(&apic->dev, &apic_mmio_ops);
@@ -1404,6 +1425,7 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu) 


	kvm_lapic_set_base(vcpu, vcpu->arch.apic_base);

	kvm_apic_set_version(vcpu);

	apic_set_spiv(apic, apic_get_reg(apic, APIC_SPIV));



	apic_update_ppr(apic);

	hrtimer_cancel(&apic->lapic_timer.timer);
@@ -1624,4 +1646,5 @@ void kvm_lapic_init(void) 
{

	/* do not patch jump label more than once per second */

	jump_label_rate_limit(&apic_hw_disabled, HZ);

	jump_label_rate_limit(&apic_sw_disabled, HZ);

}