summaryrefslogtreecommitdiffstats
path: root/arch/x86/kvm/i8254.c
diff options
context:
space:
mode:
authorMarcelo Tosatti <mtosatti@redhat.com>2008-06-06 16:37:36 -0300
committerAvi Kivity <avi@qumranet.com>2008-06-24 12:16:59 +0300
commit06e05645661211b9eaadaf6344c335d2e80f0ba2 (patch)
tree8846d2a5052aec44141e811c0a76fdb39c2e77ca /arch/x86/kvm/i8254.c
parentd4acf7e7abe45457e751525a2a4d5b693dfdd597 (diff)
downloadlinux-06e05645661211b9eaadaf6344c335d2e80f0ba2.tar.bz2
KVM: close timer injection race window in __vcpu_run
If a timer fires after kvm_inject_pending_timer_irqs() but before local_irq_disable() the code will enter guest mode and only inject such timer interrupt the next time an unrelated event causes an exit. It would be simpler if the timer->pending irq conversion could be done with IRQ's disabled, so that the above problem cannot happen. For now introduce a new vcpu requests bit to cancel guest entry. 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.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index f2f5d260874e..3829aa7b663f 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -200,9 +200,12 @@ int __pit_timer_fn(struct kvm_kpit_state *ps)
atomic_inc(&pt->pending);
smp_mb__after_atomic_inc();
- if (vcpu0 && waitqueue_active(&vcpu0->wq)) {
- vcpu0->arch.mp_state = KVM_MP_STATE_RUNNABLE;
- wake_up_interruptible(&vcpu0->wq);
+ if (vcpu0) {
+ set_bit(KVM_REQ_PENDING_TIMER, &vcpu0->requests);
+ if (waitqueue_active(&vcpu0->wq)) {
+ vcpu0->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+ wake_up_interruptible(&vcpu0->wq);
+ }
}
pt->timer.expires = ktime_add_ns(pt->timer.expires, pt->period);