@@ -13,4 +13,4 @@ hv_vmbus-y := vmbus_drv.o \
 hv_vmbus-$(CONFIG_HYPERV_TESTING)	+= hv_debugfs.o
 hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_fcopy.o hv_utils_transport.o
 
-mshv-y                          += mshv_main.o hv_call.o hv_synic.o
+mshv-y                          += mshv_main.o hv_call.o hv_synic.o hv_portid_table.o

@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/types.h>
+#include <linux/version.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <asm/mshyperv.h>
+
+#include "mshv.h"
+
+/*
+ * Ports and connections are hypervisor struct used for inter-partition
+ * communication. Port represents the source and connection represents
+ * the destination. Partitions are responsible for managing the port and
+ * connection ids.
+ *
+ */
+
+#define PORTID_MIN	1
+#define PORTID_MAX	INT_MAX
+
+static DEFINE_IDR(port_table_idr);
+
+void
+hv_port_table_fini(void)
+{
+	struct port_table_info *port_info;
+	unsigned long i, tmp;
+
+	idr_lock(&port_table_idr);
+	if (!idr_is_empty(&port_table_idr)) {
+		idr_for_each_entry_ul(&port_table_idr, port_info, tmp, i) {
+			port_info = idr_remove(&port_table_idr, i);
+			kfree_rcu(port_info, rcu);
+		}
+	}
+	idr_unlock(&port_table_idr);
+}
+
+int
+hv_portid_alloc(struct port_table_info *info)
+{
+	int ret = 0;
+
+	idr_lock(&port_table_idr);
+	ret = idr_alloc(&port_table_idr, info, PORTID_MIN,
+			PORTID_MAX, GFP_KERNEL);
+	idr_unlock(&port_table_idr);
+
+	return ret;
+}
+
+void
+hv_portid_free(int port_id)
+{
+	struct port_table_info *info;
+
+	idr_lock(&port_table_idr);
+	info = idr_remove(&port_table_idr, port_id);
+	WARN_ON(!info);
+	idr_unlock(&port_table_idr);
+
+	synchronize_rcu();
+	kfree(info);
+}
+
+int
+hv_portid_lookup(int port_id, struct port_table_info *info)
+{
+	struct port_table_info *_info;
+	int ret = -ENOENT;
+
+	rcu_read_lock();
+	_info = idr_find(&port_table_idr, port_id);
+	rcu_read_unlock();
+
+	if (_info) {
+		*info = *_info;
+		ret = 0;
+	}
+
+	return ret;
+}

@@ -39,6 +39,41 @@ void mshv_isr(void);
 int mshv_synic_init(unsigned int cpu);
 int mshv_synic_cleanup(unsigned int cpu);
 
+/*
+ * Callback for doorbell events.
+ * NOTE: This is called in interrupt context. Callback
+ * should defer slow and sleeping logic to later.
+ */
+typedef void (*doorbell_cb_t) (void *);
+
+/*
+ * port table information
+ */
+struct port_table_info {
+	struct rcu_head rcu;
+	enum hv_port_type port_type;
+	union {
+		struct {
+			u64 reserved[2];
+		} port_message;
+		struct {
+			u64 reserved[2];
+		} port_event;
+		struct {
+			u64 reserved[2];
+		} port_monitor;
+		struct {
+			doorbell_cb_t doorbell_cb;
+			void *data;
+		} port_doorbell;
+	};
+};
+
+void hv_port_table_fini(void);
+int hv_portid_alloc(struct port_table_info *info);
+int hv_portid_lookup(int port_id, struct port_table_info *info);
+void hv_portid_free(int port_id);
+
 /*
  * Hyper-V hypercalls
  */

@@ -1146,6 +1146,8 @@ __exit mshv_exit(void)
 	cpuhp_remove_state(mshv_cpuhp_online);
 	free_percpu(mshv.synic_pages);
 
+	hv_port_table_fini();
+
 	misc_deregister(&mshv_dev);
 }