[RFC PATCH V4 07/18] Implement extended event channel ABIs query

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

This bitmap is a 64 bits unsigned integer. Each bit represents one ABI. Bit
zero is reserved.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 xen/common/event_channel.c         |   12 ++++++++++++
 xen/include/public/event_channel.h |   14 ++++++++++++++
 xen/include/xen/event.h            |    2 ++
 3 files changed, 28 insertions(+)

diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index 667fd89..6b23157 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -32,6 +32,9 @@
 #include <public/event_channel.h>
 #include <xsm/xsm.h>
 
+/* A bitmap of supported extended event channel ABIs */
+uint64_t extended_event_channel = EVTCHN_EXTENDED_NONE;
+
 #define ERROR_EXIT(_errno)                                          \
     do {                                                            \
         gdprintk(XENLOG_WARNING,                                    \
@@ -1094,6 +1097,15 @@ long do_event_channel_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
         break;
     }
 
+    case EVTCHNOP_query_extended_abis: {
+        struct evtchn_query_extended_abis query;
+        query.abis = extended_event_channel;
+        rc = 0;
+        if ( __copy_to_guest(arg, &query, 1) )
+            rc = -EFAULT;
+        break;
+    }
+
     default:
         rc = -ENOSYS;
         break;
diff --git a/xen/include/public/event_channel.h b/xen/include/public/event_channel.h
index 472efdb..594ea76 100644
--- a/xen/include/public/event_channel.h
+++ b/xen/include/public/event_channel.h
@@ -71,6 +71,7 @@
 #define EVTCHNOP_bind_vcpu        8
 #define EVTCHNOP_unmask           9
 #define EVTCHNOP_reset           10
+#define EVTCHNOP_query_extended_abis 11
 /* ` } */
 
 typedef uint32_t evtchn_port_t;
@@ -258,6 +259,19 @@ struct evtchn_reset {
 typedef struct evtchn_reset evtchn_reset_t;
 
 /*
+ * EVTCHNOP_query_extended: Query the hypervisor for supported
+ * extended event channel ABIs.
+ */
+#define EVTCHN_EXTENDED_NONE 0
+#define _EVTCHN_EXTENDED_L3  1
+#define EVTCHN_EXTENDED_L3   (1UL << _EVTCHN_EXTENDED_L3)
+struct evtchn_query_extended_abis {
+    /* OUT parameters. */
+    uint64_t abis;
+};
+typedef struct evtchn_query_extended_abis evtchn_query_extended_abis_t;
+
+/*
  * ` enum neg_errnoval
  * ` HYPERVISOR_event_channel_op_compat(struct evtchn_op *op)
  * `
diff --git a/xen/include/xen/event.h b/xen/include/xen/event.h
index 6912195..fbbe9dc 100644
--- a/xen/include/xen/event.h
+++ b/xen/include/xen/event.h
@@ -157,4 +157,6 @@ void notify_via_xen_event_channel(struct domain *ld, int lport);
         mb(); /* set blocked status /then/ caller does his work */      \
     } while ( 0 )
 
+/* A bitmap of supported extended event channel ABIs */
+extern uint64_t extended_event_channel;
 #endif /* __XEN_EVENT_H__ */
-- 
1.7.10.4