[RFC PATCH V4 12/18] Update Xen public header xen.h

[Wei Liu <wei.liu2@citrix.com>]

Document limits of 2/3-level event channel ABIs.

Also need to update event.h so that this change won't break the build.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 xen/include/public/xen.h |   13 ++++++++++++-
 xen/include/xen/event.h  |    2 +-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index ba9e1ab..e6c33d4 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -554,9 +554,20 @@ DEFINE_XEN_GUEST_HANDLE(multicall_entry_t);
 
 /*
  * Event channel endpoints per domain:
+ * 2-level for x86:
  *  1024 if a long is 32 bits; 4096 if a long is 64 bits.
+ * 3-level for x86:
+ *  32k if a long is 32 bits; 256k if a long is 64 bits.
+ * 2-level for ARM:
+ *  4096 for both 32 bits and 64 bits.
+ * 3-level for ARM:
+ *  256k for both 32 bits and 64 bits.
  */
-#define NR_EVENT_CHANNELS (sizeof(xen_ulong_t) * sizeof(xen_ulong_t) * 64)
+#define NR_EVENT_CHANNELS_L2 (sizeof(xen_ulong_t) * sizeof(xen_ulong_t) * 64)
+#define NR_EVENT_CHANNELS_L3 (NR_EVENT_CHANNELS_L2 * sizeof(xen_ulong_t) * 8)
+#if !defined(__XEN__) && !defined(__XEN_TOOLS__)
+#define NR_EVENT_CHANNELS NR_EVENT_CHANNELS_L2 /* for compatibility */
+#endif
 
 struct vcpu_time_info {
     /*
diff --git a/xen/include/xen/event.h b/xen/include/xen/event.h
index e2c3736..fa1f4b6 100644
--- a/xen/include/xen/event.h
+++ b/xen/include/xen/event.h
@@ -40,7 +40,7 @@ static inline unsigned int max_evtchns(struct domain *d)
 }
 
 #define EVTCHNS_PER_BUCKET 512
-#define NR_EVTCHN_BUCKETS  (NR_EVENT_CHANNELS / EVTCHNS_PER_BUCKET)
+#define NR_EVTCHN_BUCKETS  (NR_EVENT_CHANNELS_L3 / EVTCHNS_PER_BUCKET)
 
 struct evtchn
 {
-- 
1.7.10.4