Don't veto event channel binding if it's not necessary

Currently binding is vetoed if 'UpcallEnabled' is not set, but this is not
necessary if the selected processor is 0, as the callback via will also
interrupt that CPU.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>

diff --git a/src/xenbus/evtchn.c b/src/xenbus/evtchn.c
index 4a764c071433bb6b68dbcd54c548842a7e937788..46227725e23772f14c569ae1a0db6421050d48d1 100644 (file)
--- a/src/xenbus/evtchn.c
+++ b/src/xenbus/evtchn.c
@@ -276,7 +276,7 @@ EvtchnOpenVirq(
     Processor = &Context->Processor[Cpu];
 
     status = STATUS_NOT_SUPPORTED;
-    if (!Processor->UpcallEnabled)
+    if (!Processor->UpcallEnabled && Cpu != 0)
         goto fail1;
 
     status = SystemVirtualCpuIndex(Cpu, &vcpu_id);
@@ -749,7 +749,7 @@ EvtchnBind(
     Processor = &Context->Processor[Cpu];
 
     status = STATUS_NOT_SUPPORTED;
-    if (!Processor->UpcallEnabled)
+    if (!Processor->UpcallEnabled && Cpu != 0)
         goto fail1;
 
     KeAcquireSpinLock(&Channel->Lock, &Irql);