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-rw-r--r--drivers/xen/events.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 33dcad6371f5..9161f06564eb 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1422,8 +1422,10 @@ 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;
@@ -1440,6 +1442,12 @@ static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
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
* it, but don't do the xenlinux-level rebind in that case.
@@ -1447,6 +1455,9 @@ 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;
}