[PATCH v7 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend

From: Stefano Stabellini
Date: Thu Oct 26 2017 - 15:11:58 EST


Introduce a xenbus frontend for the pvcalls protocol, as defined by
https://xenbits.xen.org/docs/unstable/misc/pvcalls.html.

This patch only adds the stubs, the code will be added by the following
patches.

Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
CC: boris.ostrovsky@xxxxxxxxxx
CC: jgross@xxxxxxxx
---
drivers/xen/pvcalls-front.c | 61 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)
create mode 100644 drivers/xen/pvcalls-front.c

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
new file mode 100644
index 0000000..a8d38c2
--- /dev/null
+++ b/drivers/xen/pvcalls-front.c
@@ -0,0 +1,61 @@
+/*
+ * (c) 2017 Stefano Stabellini <stefano@xxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+
+#include <xen/events.h>
+#include <xen/grant_table.h>
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+#include <xen/interface/io/pvcalls.h>
+
+static const struct xenbus_device_id pvcalls_front_ids[] = {
+ { "pvcalls" },
+ { "" }
+};
+
+static int pvcalls_front_remove(struct xenbus_device *dev)
+{
+ return 0;
+}
+
+static int pvcalls_front_probe(struct xenbus_device *dev,
+ const struct xenbus_device_id *id)
+{
+ return 0;
+}
+
+static void pvcalls_front_changed(struct xenbus_device *dev,
+ enum xenbus_state backend_state)
+{
+}
+
+static struct xenbus_driver pvcalls_front_driver = {
+ .ids = pvcalls_front_ids,
+ .probe = pvcalls_front_probe,
+ .remove = pvcalls_front_remove,
+ .otherend_changed = pvcalls_front_changed,
+};
+
+static int __init pvcalls_frontend_init(void)
+{
+ if (!xen_domain())
+ return -ENODEV;
+
+ pr_info("Initialising Xen pvcalls frontend driver\n");
+
+ return xenbus_register_frontend(&pvcalls_front_driver);
+}
+
+module_init(pvcalls_frontend_init);
--
1.9.1