diff options
| author | Gleb Natapov <gleb@redhat.com> | 2012-08-05 15:58:30 +0300 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2012-08-06 19:00:43 +0300 |
| commit | c5cc421ba3219b90f11d151bc55f1608c12830fa (patch) | |
| tree | fa21392981697bbc01ed14c8aab98653622c5a33 /arch/x86/kvm | |
| parent | a181dc14ed23f7a499542ff4c78532b5f24bb18f (diff) | |
KVM: use jump label to optimize checking for HW enabled APIC in APIC_BASE MSR
Usually all APICs are HW enabled so the check can be optimized out.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 29 | ||||
| -rw-r--r-- | arch/x86/kvm/lapic.h | 1 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 1 |
3 files changed, 30 insertions, 1 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index c3f14fe51e9b..5b46cab044a5 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -34,6 +34,7 @@ #include <asm/current.h> #include <asm/apicdef.h> #include <linux/atomic.h> +#include <linux/jump_label.h> #include "kvm_cache_regs.h" #include "irq.h" #include "trace.h" @@ -117,9 +118,13 @@ static inline int __apic_test_and_clear_vector(int vec, void *bitmap) return __test_and_clear_bit(VEC_POS(vec), (bitmap) + REG_POS(vec)); } +struct static_key_deferred apic_hw_disabled __read_mostly; + static inline int apic_hw_enabled(struct kvm_lapic *apic) { - return (apic)->vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE; + if (static_key_false(&apic_hw_disabled.key)) + return apic->vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE; + return MSR_IA32_APICBASE_ENABLE; } static inline int apic_sw_enabled(struct kvm_lapic *apic) @@ -1055,6 +1060,9 @@ void kvm_free_lapic(struct kvm_vcpu *vcpu) hrtimer_cancel(&vcpu->arch.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); @@ -1125,6 +1133,14 @@ void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value) return; } + /* update jump label if enable bit changes */ + if ((vcpu->arch.apic_base ^ value) & MSR_IA32_APICBASE_ENABLE) { + if (value & MSR_IA32_APICBASE_ENABLE) + static_key_slow_dec_deferred(&apic_hw_disabled); + else + static_key_slow_inc(&apic_hw_disabled.key); + } + if (!kvm_vcpu_is_bsp(apic->vcpu)) value &= ~MSR_IA32_APICBASE_BSP; @@ -1311,6 +1327,11 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu) HRTIMER_MODE_ABS); apic->lapic_timer.timer.function = apic_timer_fn; + /* + * APIC is created enabled. This will prevent kvm_lapic_set_base from + * thinking that APIC satet has changed. + */ + vcpu->arch.apic_base = MSR_IA32_APICBASE_ENABLE; kvm_lapic_set_base(vcpu, APIC_DEFAULT_PHYS_BASE | MSR_IA32_APICBASE_ENABLE); @@ -1598,3 +1619,9 @@ int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data) return kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.pv_eoi.data, addr); } + +void kvm_lapic_init(void) +{ + /* do not patch jump label more than once per second */ + jump_label_rate_limit(&apic_hw_disabled, HZ); +} diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 166766fffd9f..73fa299b68e8 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -78,4 +78,5 @@ static inline bool kvm_hv_vapic_assist_page_enabled(struct kvm_vcpu *vcpu) } int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data); +void kvm_lapic_init(void); #endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3cafbb12ae05..29fa18d27e6e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4903,6 +4903,7 @@ int kvm_arch_init(void *opaque) if (cpu_has_xsave) host_xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK); + kvm_lapic_init(); return 0; out: |