[Xen-devel] [RFC PATCH V3 07/22] Add evtchn_extended in struct domain

[Wei Liu <wei.liu2@xxxxxxxxxx>]

This field is a bitmap of currently in use extended event channel ABI, which
can have 0 (no extended event channel in use) 1 bit set. It is manipulated by
hypervisor only, so if anything goes wrong it is a bug.

The default event channel ABI is EVTCHN_EXTENDED_NONE, which means no extended
event channel is used.

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 xen/common/event_channel.c |    1 +
 xen/include/xen/event.h    |   12 +++++++++++-
 xen/include/xen/sched.h    |    1 +
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index 684a021..bd4b1e8 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -1179,6 +1179,7 @@ int evtchn_init(struct domain *d)
         return -ENOMEM;
     clear_page(d->evtchn);
 
+    d->evtchn_extended = EVTCHN_EXTENDED_NONE;
     spin_lock_init(&d->event_lock);
     if ( get_free_port(d) != 0 ) {
         free_xenheap_page(d->evtchn);
diff --git a/xen/include/xen/event.h b/xen/include/xen/event.h
index f8de10b..240344b 100644
--- a/xen/include/xen/event.h
+++ b/xen/include/xen/event.h
@@ -14,6 +14,7 @@
 #include <xen/softirq.h>
 #include <asm/bitops.h>
 #include <asm/event.h>
+#include <public/event_channel.h>
 
 #ifndef CONFIG_COMPAT
 #define BITS_PER_EVTCHN_WORD(d) BITS_PER_LONG
@@ -22,7 +23,16 @@
 #endif
 static inline unsigned int max_evtchns(struct domain *d)
 {
-    return BITS_PER_EVTCHN_WORD(d) * BITS_PER_EVTCHN_WORD(d);
+    unsigned int ret = 0;
+    switch ( d->evtchn_extended )
+    {
+    case EVTCHN_EXTENDED_NONE:
+        ret = BITS_PER_EVTCHN_WORD(d) * BITS_PER_EVTCHN_WORD(d);
+        break;
+    default:
+        BUG();
+    }
+    return ret;
 }
 
 #define EVTCHNS_PER_BUCKET 128
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index bb65cbf..dd40444 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -217,6 +217,7 @@ struct domain
     /* Event channel information. */
     struct evtchn  **evtchn;
     spinlock_t       event_lock;
+    unsigned int     evtchn_extended;
 
     struct grant_table *grant_table;
 
-- 
1.7.10.4


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