KVM: migrate PIT timer

Migrate the PIT timer to the physical CPU which vcpu0 is scheduled on,
similarly to what is done for the LAPIC timers, otherwise PIT interrupts
will be delayed until an unrelated event causes an exit.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 7c077a9d9777..f2f5d260874e 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -200,7 +200,6 @@ int __pit_timer_fn(struct kvm_kpit_state *ps)
 
         atomic_inc(&pt->pending);
         smp_mb__after_atomic_inc();
-        /* FIXME: handle case where the guest is in guest mode */
         if (vcpu0 && waitqueue_active(&vcpu0->wq)) {
                 vcpu0->arch.mp_state = KVM_MP_STATE_RUNNABLE;
                 wake_up_interruptible(&vcpu0->wq);
@@ -237,6 +236,19 @@ static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
                 return HRTIMER_NORESTART;
 }
 
+void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
+{
+        struct kvm_pit *pit = vcpu->kvm->arch.vpit;
+        struct hrtimer *timer;
+
+        if (vcpu->vcpu_id != 0 || !pit)
+                return;
+
+        timer = &pit->pit_state.pit_timer.timer;
+        if (hrtimer_cancel(timer))
+                hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS);
+}
+
 static void destroy_pit_timer(struct kvm_kpit_timer *pt)
 {
         pr_debug("pit: execute del timer!\n");