[Xen-devel] [RFC PATCH V3 06/22] Define extended event channel registration interface

[Wei Liu <wei.liu2@xxxxxxxxxx>]

This interface allows user to query supported event channel types. If we need
to disable a specific ABI in the future, we just need to remove the dead code
and clear corresponding feature bit.

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 xen/include/public/event_channel.h |   44 ++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/xen/include/public/event_channel.h 
b/xen/include/public/event_channel.h
index 07ff321..dff3364 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_register_extended 11
 /* ` } */
 
 typedef uint32_t evtchn_port_t;
@@ -258,6 +259,49 @@ struct evtchn_reset {
 typedef struct evtchn_reset evtchn_reset_t;
 
 /*
+ * EVTCHNOP_register_extended: Register extended event channel
+ * NOTES:
+ *  1. Currently only 3-level is supported.
+ *  2. Should fall back to 2-level if this call fails.
+ */
+/* 64 bit guests need 8 pages for evtchn_pending and evtchn_mask for
+ * 256k event channels while 32 bit ones only need 1 page for 32k
+ * event channels. */
+#define EVTCHN_MAX_L3_PAGES 8
+struct evtchn_register_3level {
+    /* IN parameters. */
+    uint32_t nr_pages;          /* for evtchn_{pending,mask} */
+    uint32_t nr_vcpus;          /* for l2sel_{mfns,offsets} */
+    XEN_GUEST_HANDLE(xen_pfn_t) evtchn_pending;
+    XEN_GUEST_HANDLE(xen_pfn_t) evtchn_mask;
+    XEN_GUEST_HANDLE(xen_pfn_t) l2sel_mfns;
+    XEN_GUEST_HANDLE(xen_pfn_t) l2sel_offsets;
+};
+typedef struct evtchn_register_3level evtchn_register_3level_t;
+DEFINE_XEN_GUEST_HANDLE(evtchn_register_3level_t);
+
+/* commands:
+ * EVTCHN_EXTENDED_QUERY(0): query supported extended event channel types,
+ *                _NONE      supported types are or'ed in return value of
+ *                           the hypercall.
+ * EVTCHN_EXTENDED_*:        specific extended event channel subcommand.
+ */
+#define EVTCHN_EXTENDED_QUERY 0
+/* supported extended event channel */
+#define EVTCHN_EXTENDED_NONE  0
+#define _EVTCHN_EXTENDED_L3   0
+#define EVTCHN_EXTENDED_L3    (1U << _EVTCHN_EXTENDED_L3)
+struct evtchn_register_extended {
+    /* IN parameters. */
+    uint32_t cmd;
+    union {
+        evtchn_register_3level_t l3;
+    } u;
+};
+typedef struct evtchn_register_extended evtchn_register_extended_t;
+DEFINE_XEN_GUEST_HANDLE(evtchn_register_extended_t);
+
+/*
  * ` enum neg_errnoval
  * ` HYPERVISOR_event_channel_op_compat(struct evtchn_op *op)
  * `
-- 
1.7.10.4


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