From 3cf57fed216e2c1b6fdfeccb792650bab72a350a Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Sat, 26 Jul 2008 17:01:01 -0300 Subject: KVM: PIT: fix injection logic and count The PIT injection logic is problematic under the following cases: 1) If there is a higher priority vector to be delivered by the time kvm_pit_timer_intr_post is invoked ps->inject_pending won't be set. This opens the possibility for missing many PIT event injections (say if guest executes hlt at this point). 2) ps->inject_pending is racy with more than two vcpus. Since there's no locking around read/dec of pt->pending, two vcpu's can inject two interrupts for a single pt->pending count. Fix 1 by using an irq ack notifier: only reinject when the previous irq has been acked. Fix 2 with appropriate locking around manipulation of pending count and irq_ack by the injection / ack paths. Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- arch/x86/kvm/i8254.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'arch/x86/kvm/i8254.h') diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h index db25c2a..e436d49 100644 --- a/arch/x86/kvm/i8254.h +++ b/arch/x86/kvm/i8254.h @@ -8,7 +8,6 @@ struct kvm_kpit_timer { int irq; s64 period; /* unit: ns */ s64 scheduled; - ktime_t last_update; atomic_t pending; }; @@ -34,8 +33,9 @@ struct kvm_kpit_state { u32 speaker_data_on; struct mutex lock; struct kvm_pit *pit; - bool inject_pending; /* if inject pending interrupts */ - unsigned long last_injected_time; + spinlock_t inject_lock; + unsigned long irq_ack; + struct kvm_irq_ack_notifier irq_ack_notifier; }; struct kvm_pit { @@ -54,7 +54,6 @@ struct kvm_pit { #define KVM_PIT_CHANNEL_MASK 0x3 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu); -void kvm_pit_timer_intr_post(struct kvm_vcpu *vcpu, int vec); void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val); struct kvm_pit *kvm_create_pit(struct kvm *kvm); void kvm_free_pit(struct kvm *kvm); -- cgit v1.1