From 5852dd2b1a1bcb58e9611e9b74a69db8dcad27d0 Mon Sep 17 00:00:00 2001
From: Dmytro Firsov <dmytro_firsov@epam.com>
Date: Tue, 14 Feb 2023 14:40:38 +0200
Subject: [PATCH] xen: events: add event channel allocation for domain-0

This commit adds interface for evtchn allocation that can be used by
privilaged domain. Domain 0 can specify both dom and remote_dom
parameters for hypercall, where in others domains dom should be always
DOMID_SELF. It is needed for creating pre-defined channels during
domain setup in Zephyr Dom0.

Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>
---
 drivers/xen/events.c        | 18 ++++++++++++++++++
 include/zephyr/xen/events.h | 11 +++++++++++
 2 files changed, 29 insertions(+)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index e077b0f6cf..a16cce8b5c 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -47,6 +47,24 @@ int alloc_unbound_event_channel(domid_t remote_dom)
 	return rc;
 }
 
+#ifdef CONFIG_XEN_DOM0
+int alloc_unbound_event_channel_dom0(domid_t dom, domid_t remote_dom)
+{
+	int rc;
+	struct evtchn_alloc_unbound alloc = {
+		.dom = dom,
+		.remote_dom = remote_dom,
+	};
+
+	rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &alloc);
+	if (rc == 0) {
+		rc = alloc.port;
+	}
+
+	return rc;
+}
+#endif /* CONFIG_XEN_DOM0 */
+
 int bind_interdomain_event_channel(domid_t remote_dom, evtchn_port_t remote_port,
 		evtchn_cb_t cb, void *data)
 {
diff --git a/include/zephyr/xen/events.h b/include/zephyr/xen/events.h
index d2a936a59e..cbad8162cb 100644
--- a/include/zephyr/xen/events.h
+++ b/include/zephyr/xen/events.h
@@ -36,6 +36,17 @@ void notify_evtchn(evtchn_port_t port);
  */
 int alloc_unbound_event_channel(domid_t remote_dom);
 
+#ifdef CONFIG_XEN_DOM0
+/*
+ * Allocate event-channel between remote domains. Can be used only from Dom0.
+ *
+ * @param dom - first remote domain domid (may be DOMID_SELF)
+ * @param remote_dom - second remote domain domid
+ * @return - local event channel port on success, negative on error
+ */
+int alloc_unbound_event_channel_dom0(domid_t dom, domid_t remote_dom);
+#endif /* CONFIG_XEN_DOM0 */
+
 /*
  * Allocate local event channel, binded to remote port and attach specified callback
  * to it