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KVM: use jump label to optimize checking for SW enabled apic in spurious interrupt register

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

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Gleb Natapov 2012-08-05 15:58:31 +03:00 committed by Avi Kivity
parent c5cc421ba3
commit f8c1ea1039
1 changed files with 31 additions and 8 deletions
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39
arch/x86/kvm/lapic.c
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@ -127,9 +127,24 @@ static inline int apic_hw_enabled(struct kvm_lapic *apic)
return MSR_IA32_APICBASE_ENABLE;
}
static inline int apic_sw_enabled(struct kvm_lapic *apic)
struct static_key_deferred apic_sw_disabled __read_mostly;
static inline void apic_set_spiv(struct kvm_lapic *apic, u32 val)
{
return apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_APIC_ENABLED;
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);
}