xen/events: mask events when changing their VCPU binding

[pandora-kernel.git] / drivers / xen / events.c

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 58236dd..f6227cc 100644 (file)
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1340,8 +1340,10 @@ void rebind_evtchn_irq(int evtchn, int irq)
 /* Rebind an evtchn so that it gets delivered to a specific cpu */
 static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
 {
+       struct shared_info *s = HYPERVISOR_shared_info;
        struct evtchn_bind_vcpu bind_vcpu;
        int evtchn = evtchn_from_irq(irq);
+       int masked;
 
        if (!VALID_EVTCHN(evtchn))
                return -1;
@@ -1357,6 +1359,12 @@ static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
        bind_vcpu.port = evtchn;
        bind_vcpu.vcpu = tcpu;
 
+       /*
+        * Mask the event while changing the VCPU binding to prevent
+        * it being delivered on an unexpected VCPU.
+        */
+       masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
+
        /*
         * If this fails, it usually just indicates that we're dealing with a
         * virq or IPI channel, which don't actually need to be rebound. Ignore
@@ -1365,6 +1373,9 @@ static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
        if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
                bind_evtchn_to_cpu(evtchn, tcpu);
 
+       if (!masked)
+               unmask_evtchn(evtchn);
+
        return 0;
 }