2 files changed, 48 insertions, 11 deletions

diff --git a/xen/include/xen/event.h b/xen/include/xen/event.h
index 6933f02608..cba09e7a60 100644
--- a/xen/include/xen/event.h
+++ b/xen/include/xen/event.h
@@ -69,15 +69,37 @@ int guest_enabled_event(struct vcpu *v, uint32_t virq);
 /* Notify remote end of a Xen-attached event channel.*/
 void notify_via_xen_event_channel(struct domain *ld, int lport);
 
-/* Internal event channel object accessors */
-#define bucket_from_port(d,p) \
-    ((d)->evtchn[(p)/EVTCHNS_PER_BUCKET])
-#define port_is_valid(d,p)    \
-    (((p) >= 0) && ((p) < (d)->max_evtchns) &&  \
-     (bucket_from_port(d,p) != NULL))
-#define evtchn_from_port(d,p) \
-    (&(bucket_from_port(d,p))[(p)&(EVTCHNS_PER_BUCKET-1)])
+/*
+ * Internal event channel object storage.
+ *
+ * The objects (struct evtchn) are indexed using a two level scheme of
+ * groups and buckets.  Each group is a page of bucket pointers.  Each
+ * bucket is a page-sized array of struct evtchn's.
+ *
+ * The first bucket is directly accessed via d->evtchn.
+ */
+#define group_from_port(d, p) \
+    ((d)->evtchn_group[(p) / EVTCHNS_PER_GROUP])
+#define bucket_from_port(d, p) \
+    ((group_from_port(d, p))[((p) % EVTCHNS_PER_GROUP) / EVTCHNS_PER_BUCKET])
 
+static inline bool_t port_is_valid(struct domain *d, unsigned int p)
+{
+    if ( p >= d->max_evtchns )
+        return 0;
+    if ( !d->evtchn )
+        return 0;
+    if ( p < EVTCHNS_PER_BUCKET )
+        return 1;
+    return group_from_port(d, p) != NULL && bucket_from_port(d, p) != NULL;
+}
+
+static inline struct evtchn *evtchn_from_port(struct domain *d, unsigned int p)
+{
+    if ( p < EVTCHNS_PER_BUCKET )
+        return &d->evtchn[p];
+    return bucket_from_port(d, p) + (p % EVTCHNS_PER_BUCKET);
+}
 
 /* Wait on a Xen-attached event channel. */
 #define wait_on_xen_event_channel(port, condition)                      \
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index f8fc7c254a..2090a413d8 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -50,8 +50,22 @@ extern struct domain *dom0;
 #else
 #define BITS_PER_EVTCHN_WORD(d) (has_32bit_shinfo(d) ? 32 : BITS_PER_XEN_ULONG)
 #endif
-#define EVTCHNS_PER_BUCKET 128
-#define NR_EVTCHN_BUCKETS  (NR_EVENT_CHANNELS / EVTCHNS_PER_BUCKET)
+
+#define BUCKETS_PER_GROUP  (PAGE_SIZE/sizeof(struct evtchn *))
+/* Round size of struct evtchn up to power of 2 size */
+#define __RDU2(x)   (       (x) | (   (x) >> 1))
+#define __RDU4(x)   ( __RDU2(x) | ( __RDU2(x) >> 2))
+#define __RDU8(x)   ( __RDU4(x) | ( __RDU4(x) >> 4))
+#define __RDU16(x)  ( __RDU8(x) | ( __RDU8(x) >> 8))
+#define __RDU32(x)  (__RDU16(x) | (__RDU16(x) >>16))
+#define next_power_of_2(x)      (__RDU32((x)-1) + 1)
+
+/* Maximum number of event channels for any ABI. */
+#define MAX_NR_EVTCHNS NR_EVENT_CHANNELS
+
+#define EVTCHNS_PER_BUCKET (PAGE_SIZE / next_power_of_2(sizeof(struct evtchn)))
+#define EVTCHNS_PER_GROUP  (BUCKETS_PER_GROUP * EVTCHNS_PER_BUCKET)
+#define NR_EVTCHN_GROUPS   DIV_ROUND_UP(MAX_NR_EVTCHNS, EVTCHNS_PER_GROUP)
 
 struct evtchn
 {
@@ -271,7 +285,8 @@ struct domain
     spinlock_t       rangesets_lock;
 
     /* Event channel information. */
-    struct evtchn   *evtchn[NR_EVTCHN_BUCKETS];
+    struct evtchn   *evtchn;                         /* first bucket only */
+    struct evtchn  **evtchn_group[NR_EVTCHN_GROUPS]; /* all other buckets */
     unsigned int     max_evtchns;
     spinlock_t       event_lock;
     const struct evtchn_port_ops *evtchn_port_ops;