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 --- virt/kvm/kvm_main.c | 1 + 1 file changed, 1 insertion(+) (limited to 'virt') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d5911d9895c3..47cbc6e3fafd 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -765,6 +765,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) * We will block until either an interrupt or a signal wakes us up */ while (!kvm_cpu_has_interrupt(vcpu) + && !kvm_cpu_has_pending_timer(vcpu) && !signal_pending(current) && !kvm_arch_vcpu_runnable(vcpu)) { set_current_state(TASK_INTERRUPTIBLE); -- cgit v1.2.2