Merge tag 'stable/for-linus-3.11-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull Xen bug-fixes from Konrad Rzeszutek Wilk:
 - On ARM did not have balanced calls to get/put_cpu.
 - Fix to make tboot + Xen + Linux correctly.
 - Fix events VCPU binding issues.
 - Fix a vCPU online race where IPIs are sent to not-yet-online vCPU.

* tag 'stable/for-linus-3.11-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/smp: initialize IPI vectors before marking CPU online
  xen/events: mask events when changing their VCPU binding
  xen/events: initialize local per-cpu mask for all possible events
  x86/xen: do not identity map UNUSABLE regions in the machine E820
  xen/arm: missing put_cpu in xen_percpu_init

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index a58ac435a9a4..5e8be462aed5 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -348,7 +348,7 @@ static void init_evtchn_cpu_bindings(void)
 
 	for_each_possible_cpu(i)
 		memset(per_cpu(cpu_evtchn_mask, i),
-		       (i == 0) ? ~0 : 0, sizeof(*per_cpu(cpu_evtchn_mask, i)));
+		       (i == 0) ? ~0 : 0, NR_EVENT_CHANNELS/8);
 }
 
 static inline void clear_evtchn(int port)
@@ -1493,8 +1493,10 @@ 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;
@@ -1511,6 +1513,12 @@ 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, BM(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.
@@ -1518,6 +1526,9 @@ 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;
 }