i think it works

code/kernel/ke_queue.h

@@ -0,0 +1,32 @@
+#pragma once
+// ke_queue.h - fixed-depth message queue
+// Processes share an address space, so a pointer in Param[] is valid
+// on both sides. The queue is only a synchronisation and ordering tool.
+#include "ob_object.h"
+#include "ke_spinlock.h"
+#include "ke_list.h"
+#include "ke_status.h"
+#include <stdint.h>
+#include <stdbool.h>
+
+#define QUEUE_MESSAGE_SIZE   64     /* bytes, fixed */
+#define QUEUE_DEPTH          256
+
+typedef struct QUEUE_MESSAGE {
+    uint32_t Type;
+    uint32_t Flags;
+    uint64_t Param[6];      /* 48 bytes of payload */
+} QUEUE_MESSAGE;            /* total: 64 bytes     */
+
+typedef struct QUEUE {
+    OBJECT          Header;
+    SPINLOCK        Lock;
+    QUEUE_MESSAGE   Ring[QUEUE_DEPTH];
+    uint32_t        Head, Tail, Count;
+    LIST_ENTRY      SendWaiters;
+    LIST_ENTRY      RecvWaiters;
+} QUEUE;
+
+KSTATUS QueueCreate(QUEUE **out);
+KSTATUS KeSendMessage(QUEUE* queue, const QUEUE_MESSAGE* msg, bool blocking);
+KSTATUS KeReceiveMessage(QUEUE* queue, QUEUE_MESSAGE* msg, bool blocking);