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KVM: use jump label to optimize checking for in kernel local apic presence

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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>
This commit is contained in:
Gleb Natapov 2012-08-05 15:58:32 +03:00 committed by Avi Kivity
parent f8c1ea1039
commit 54e9818f39
3 changed files with 41 additions and 29 deletions
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62
arch/x86/kvm/lapic.c
View File

@ -152,6 +152,13 @@ static inline int apic_enabled(struct kvm_lapic *apic)
return apic_sw_enabled(apic) && apic_hw_enabled(apic);
}
static inline bool vcpu_has_lapic(struct kvm_vcpu *vcpu)
{
if (static_key_false(&kvm_no_apic_vcpu))
return vcpu->arch.apic;
return true;
}
#define LVT_MASK \
(APIC_LVT_MASKED | APIC_SEND_PENDING | APIC_VECTOR_MASK)
@ -204,7 +211,7 @@ void kvm_apic_set_version(struct kvm_vcpu *vcpu)
struct kvm_cpuid_entry2 *feat;
u32 v = APIC_VERSION;
if (!irqchip_in_kernel(vcpu->kvm))
if (!vcpu_has_lapic(vcpu))
return;
feat = kvm_find_cpuid_entry(apic->vcpu, 0x1, 0);
@ -305,7 +312,6 @@ static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
int highest_irr;
/* This may race with setting of irr in __apic_accept_irq() and
@ -313,9 +319,9 @@ int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
* will cause vmexit immediately and the value will be recalculated
* on the next vmentry.
*/
if (!apic)
if (!vcpu_has_lapic(vcpu))
return 0;
highest_irr = apic_find_highest_irr(apic);
highest_irr = apic_find_highest_irr(vcpu->arch.apic);
return highest_irr;
}
@ -1061,9 +1067,7 @@ static int apic_mmio_write(struct kvm_io_device *this,
void kvm_lapic_set_eoi(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
if (apic)
if (vcpu_has_lapic(vcpu))
apic_reg_write(vcpu->arch.apic, APIC_EOI, 0);
}
EXPORT_SYMBOL_GPL(kvm_lapic_set_eoi);
@ -1098,10 +1102,9 @@ void kvm_free_lapic(struct kvm_vcpu *vcpu)
u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
if (!apic)
return 0;
if (apic_lvtt_oneshot(apic) || apic_lvtt_period(apic))
if (!vcpu_has_lapic(vcpu) || apic_lvtt_oneshot(apic) ||
apic_lvtt_period(apic))
return 0;
return apic->lapic_timer.tscdeadline;
@ -1110,10 +1113,9 @@ u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu)
void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data)
{
struct kvm_lapic *apic = vcpu->arch.apic;
if (!apic)
return;
if (apic_lvtt_oneshot(apic) || apic_lvtt_period(apic))
if (!vcpu_has_lapic(vcpu) || apic_lvtt_oneshot(apic) ||
apic_lvtt_period(apic))
return;
hrtimer_cancel(&apic->lapic_timer.timer);
@ -1125,20 +1127,21 @@ void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8)
{
struct kvm_lapic *apic = vcpu->arch.apic;
if (!apic)
if (!vcpu_has_lapic(vcpu))
return;
apic_set_tpr(apic, ((cr8 & 0x0f) << 4)
| (apic_get_reg(apic, APIC_TASKPRI) & 4));
}
u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
u64 tpr;
if (!apic)
if (!vcpu_has_lapic(vcpu))
return 0;
tpr = (u64) apic_get_reg(apic, APIC_TASKPRI);
tpr = (u64) apic_get_reg(vcpu->arch.apic, APIC_TASKPRI);
return (tpr & 0xf0) >> 4;
}
@ -1237,7 +1240,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu)
bool kvm_apic_present(struct kvm_vcpu *vcpu)
{
return vcpu->arch.apic && apic_hw_enabled(vcpu->arch.apic);
return vcpu_has_lapic(vcpu) && apic_hw_enabled(vcpu->arch.apic);
}
int kvm_lapic_enabled(struct kvm_vcpu *vcpu)
@ -1258,10 +1261,11 @@ static bool lapic_is_periodic(struct kvm_lapic *apic)
int apic_has_pending_timer(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *lapic = vcpu->arch.apic;
struct kvm_lapic *apic = vcpu->arch.apic;
if (lapic && apic_enabled(lapic) && apic_lvt_enabled(lapic, APIC_LVTT))
return atomic_read(&lapic->lapic_timer.pending);
if (vcpu_has_lapic(vcpu) && apic_enabled(apic) &&
apic_lvt_enabled(apic, APIC_LVTT))
return atomic_read(&apic->lapic_timer.pending);
return 0;
}
@ -1371,7 +1375,7 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
struct kvm_lapic *apic = vcpu->arch.apic;
int highest_irr;
if (!apic || !apic_enabled(apic))
if (!vcpu_has_lapic(vcpu) || !apic_enabled(apic))
return -1;
apic_update_ppr(apic);
@ -1399,7 +1403,10 @@ void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
if (apic && atomic_read(&apic->lapic_timer.pending) > 0) {
if (!vcpu_has_lapic(vcpu))
return;
if (atomic_read(&apic->lapic_timer.pending) > 0) {
if (kvm_apic_local_deliver(apic, APIC_LVTT))
atomic_dec(&apic->lapic_timer.pending);
}
@ -1439,13 +1446,12 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu)
void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
struct hrtimer *timer;
if (!apic)
if (!vcpu_has_lapic(vcpu))
return;
timer = &apic->lapic_timer.timer;
timer = &vcpu->arch.apic->lapic_timer.timer;
if (hrtimer_cancel(timer))
hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
}
@ -1602,7 +1608,7 @@ int kvm_hv_vapic_msr_write(struct kvm_vcpu *vcpu, u32 reg, u64 data)
{
struct kvm_lapic *apic = vcpu->arch.apic;
if (!irqchip_in_kernel(vcpu->kvm))
if (!vcpu_has_lapic(vcpu))
return 1;
/* if this is ICR write vector before command */
@ -1616,7 +1622,7 @@ int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu, u32 reg, u64 *data)
struct kvm_lapic *apic = vcpu->arch.apic;
u32 low, high = 0;
if (!irqchip_in_kernel(vcpu->kvm))
if (!vcpu_has_lapic(vcpu))
return 1;
if (apic_reg_read(apic, reg, 4, &low))

7
arch/x86/kvm/x86.c
View File

@ -6152,6 +6152,8 @@ bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu)
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 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
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 @@ void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
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)

1
arch/x86/kvm/x86.h
View File

@ -124,4 +124,5 @@ int kvm_write_guest_virt_system(struct x86_emulate_ctxt *ctxt,
extern u64 host_xcr0;
extern struct static_key kvm_no_apic_vcpu;
#endif