diff options
Diffstat (limited to 'arch/x86/kvm/lapic.c')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index ddd83fb65da5..92f13ac70ad4 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -321,8 +321,16 @@ void kvm_apic_set_version(struct kvm_vcpu *vcpu) if (!lapic_in_kernel(vcpu)) return; + /* + * KVM emulates 82093AA datasheet (with in-kernel IOAPIC implementation) + * which doesn't have EOI register; Some buggy OSes (e.g. Windows with + * Hyper-V role) disable EOI broadcast in lapic not checking for IOAPIC + * version first and level-triggered interrupts never get EOIed in + * IOAPIC. + */ feat = kvm_find_cpuid_entry(apic->vcpu, 0x1, 0); - if (feat && (feat->ecx & (1 << (X86_FEATURE_X2APIC & 31)))) + if (feat && (feat->ecx & (1 << (X86_FEATURE_X2APIC & 31))) && + !ioapic_in_kernel(vcpu->kvm)) v |= APIC_LVR_DIRECTED_EOI; kvm_lapic_set_reg(apic, APIC_LVR, v); } @@ -1467,11 +1475,23 @@ static bool set_target_expiration(struct kvm_lapic *apic) static void advance_periodic_target_expiration(struct kvm_lapic *apic) { - apic->lapic_timer.tscdeadline += - nsec_to_cycles(apic->vcpu, apic->lapic_timer.period); + ktime_t now = ktime_get(); + u64 tscl = rdtsc(); + ktime_t delta; + + /* + * Synchronize both deadlines to the same time source or + * differences in the periods (caused by differences in the + * underlying clocks or numerical approximation errors) will + * cause the two to drift apart over time as the errors + * accumulate. + */ apic->lapic_timer.target_expiration = ktime_add_ns(apic->lapic_timer.target_expiration, apic->lapic_timer.period); + delta = ktime_sub(apic->lapic_timer.target_expiration, now); + apic->lapic_timer.tscdeadline = kvm_read_l1_tsc(apic->vcpu, tscl) + + nsec_to_cycles(apic->vcpu, delta); } static void start_sw_period(struct kvm_lapic *apic) |