From 3d80840d96127401ba6aeadd813c3a15b84e70fe Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Fri, 11 Apr 2008 14:53:26 -0300 Subject: KVM: hlt emulation should take in-kernel APIC/PIT timers into account Timers that fire between guest hlt and vcpu_block's add_wait_queue() are ignored, possibly resulting in hangs. Also make sure that atomic_inc and waitqueue_active tests happen in the specified order, otherwise the following race is open: CPU0 CPU1 if (waitqueue_active(wq)) add_wait_queue() if (!atomic_read(pit_timer->pending)) schedule() atomic_inc(pit_timer->pending) Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- arch/x86/kvm/irq.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'arch/x86/kvm/irq.c') diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c index dbfe21c99c4..ce1f583459b 100644 --- a/arch/x86/kvm/irq.c +++ b/arch/x86/kvm/irq.c @@ -25,6 +25,21 @@ #include "irq.h" #include "i8254.h" +/* + * check if there are pending timer events + * to be processed. + */ +int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu) +{ + int ret; + + ret = pit_has_pending_timer(vcpu); + ret |= apic_has_pending_timer(vcpu); + + return ret; +} +EXPORT_SYMBOL(kvm_cpu_has_pending_timer); + /* * check if there is pending interrupt without * intack. -- cgit v1.2.3