diff options
| author | Marcelo Tosatti <mtosatti@redhat.com> | 2008-04-11 14:53:26 -0300 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2008-04-27 12:04:11 +0300 |
| commit | 3d80840d96127401ba6aeadd813c3a15b84e70fe (patch) | |
| tree | b3e083c651f09fee362d88f0d1fc140194f2431d /arch/x86/kvm/i8254.c | |
| parent | 3564990af1b9f77a63692c1079e9c41af229f066 (diff) | |
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 <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/x86/kvm/i8254.c')
| -rw-r--r-- | arch/x86/kvm/i8254.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 9f118e2f350d..ed1af80432b3 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -212,6 +212,16 @@ int __pit_timer_fn(struct kvm_kpit_state *ps) return (pt->period == 0 ? 0 : 1); } +int pit_has_pending_timer(struct kvm_vcpu *vcpu) +{ + struct kvm_pit *pit = vcpu->kvm->arch.vpit; + + if (pit && vcpu->vcpu_id == 0) + return atomic_read(&pit->pit_state.pit_timer.pending); + + return 0; +} + static enum hrtimer_restart pit_timer_fn(struct hrtimer *data) { struct kvm_kpit_state *ps; |