From dc7404cea34ef997dfe89ca94d16358e9d29c8d8 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@qumranet.com>
Date: Sun, 17 Aug 2008 16:03:46 +0300
Subject: KVM: Handle spurious acks for PIT interrupts

Spurious acks can be generated, for example if the PIC is being reset.
Handle those acks gracefully rather than flooding the log with warnings.

Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 7d04dd3..c842060 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -228,7 +228,7 @@ void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 						 irq_ack_notifier);
 	spin_lock(&ps->inject_lock);
 	if (atomic_dec_return(&ps->pit_timer.pending) < 0)
-		WARN_ON(1);
+		atomic_inc(&ps->pit_timer.pending);
 	ps->irq_ack = 1;
 	spin_unlock(&ps->inject_lock);
 }
-- 
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