[PATCH 1/3] KVM: APIC: remove unnecessary double checks on APIC existence

From: Paolo Bonzini
Date: Mon Feb 08 2016 - 11:15:56 EST


Usually the in-kernel APIC's existence is checked in the caller. Do not
bother checking it again in lapic.c.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/lapic.c | 19 +++----------------
1 file changed, 3 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 1520d1acd0ad..b1029051f664 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -475,18 +475,12 @@ static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)

int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
{
- int highest_irr;
-
/* This may race with setting of irr in __apic_accept_irq() and
* value returned may be wrong, but kvm_vcpu_kick() in __apic_accept_irq
* will cause vmexit immediately and the value will be recalculated
* on the next vmentry.
*/
- if (!kvm_vcpu_has_lapic(vcpu))
- return 0;
- highest_irr = apic_find_highest_irr(vcpu->arch.apic);
-
- return highest_irr;
+ return apic_find_highest_irr(vcpu->arch.apic);
}

static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
@@ -1601,8 +1595,7 @@ static int apic_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this,

void kvm_lapic_set_eoi(struct kvm_vcpu *vcpu)
{
- if (kvm_vcpu_has_lapic(vcpu))
- apic_reg_write(vcpu->arch.apic, APIC_EOI, 0);
+ apic_reg_write(vcpu->arch.apic, APIC_EOI, 0);
}
EXPORT_SYMBOL_GPL(kvm_lapic_set_eoi);

@@ -1676,9 +1669,6 @@ void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8)
{
struct kvm_lapic *apic = vcpu->arch.apic;

- if (!kvm_vcpu_has_lapic(vcpu))
- return;
-
apic_set_tpr(apic, ((cr8 & 0x0f) << 4)
| (kvm_apic_get_reg(apic, APIC_TASKPRI) & 4));
}
@@ -1687,9 +1677,6 @@ u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu)
{
u64 tpr;

- if (!kvm_vcpu_has_lapic(vcpu))
- return 0;
-
tpr = (u64) kvm_apic_get_reg(vcpu->arch.apic, APIC_TASKPRI);

return (tpr & 0xf0) >> 4;
@@ -1912,7 +1899,7 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
struct kvm_lapic *apic = vcpu->arch.apic;
int highest_irr;

- if (!kvm_vcpu_has_lapic(vcpu) || !apic_enabled(apic))
+ if (!apic_enabled(apic))
return -1;

apic_update_ppr(apic);
--
1.8.3.1