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| 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 /virt | |
| parent | 3564990af1b9f77a63692c1079e9c41af229f066 (diff) | |
| download | lwn-3d80840d96127401ba6aeadd813c3a15b84e70fe.tar.gz lwn-3d80840d96127401ba6aeadd813c3a15b84e70fe.zip | |
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 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 1 |
1 files changed, 1 insertions, 0 deletions
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); |