--- zzzz-none-000/linux-3.10.107/drivers/xen/xenbus/xenbus_dev_backend.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/xen/xenbus/xenbus_dev_backend.c	2021-02-04 17:41:59.000000000 +0000
@@ -1,3 +1,5 @@
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/mm.h>
@@ -47,7 +49,7 @@
 		goto out_err;
 
 	gnttab_grant_foreign_access_ref(GNTTAB_RESERVED_XENSTORE, domid,
-			virt_to_mfn(xen_store_interface), 0 /* writable */);
+			virt_to_gfn(xen_store_interface), 0 /* writable */);
 
 	arg.dom = DOMID_SELF;
 	arg.remote_dom = domid;
@@ -127,7 +129,7 @@
 
 	err = misc_register(&xenbus_backend_dev);
 	if (err)
-		printk(KERN_ERR "Could not register xenbus backend device\n");
+		pr_err("Could not register xenbus backend device\n");
 	return err;
 }