v4.19.13 snapshot.
diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
new file mode 100644
index 0000000..71ddfb4
--- /dev/null
+++ b/drivers/xen/xenfs/super.c
@@ -0,0 +1,101 @@
+/*
+ * xenfs.c - a filesystem for passing info between the a domain and
+ * the hypervisor.
+ *
+ * 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem
+ * and /proc/xen compatibility mount point.
+ * Turned xenfs into a loadable module.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/magic.h>
+
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+
+#include "xenfs.h"
+#include "../privcmd.h"
+
+#include <asm/xen/hypervisor.h>
+
+MODULE_DESCRIPTION("Xen filesystem");
+MODULE_LICENSE("GPL");
+
+static ssize_t capabilities_read(struct file *file, char __user *buf,
+ size_t size, loff_t *off)
+{
+ char *tmp = "";
+
+ if (xen_initial_domain())
+ tmp = "control_d\n";
+
+ return simple_read_from_buffer(buf, size, off, tmp, strlen(tmp));
+}
+
+static const struct file_operations capabilities_file_ops = {
+ .read = capabilities_read,
+ .llseek = default_llseek,
+};
+
+static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
+{
+ static const struct tree_descr xenfs_files[] = {
+ [2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
+ { "capabilities", &capabilities_file_ops, S_IRUGO },
+ { "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
+ {""},
+ };
+
+ static const struct tree_descr xenfs_init_files[] = {
+ [2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
+ { "capabilities", &capabilities_file_ops, S_IRUGO },
+ { "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
+ { "xsd_kva", &xsd_kva_file_ops, S_IRUSR|S_IWUSR},
+ { "xsd_port", &xsd_port_file_ops, S_IRUSR|S_IWUSR},
+#ifdef CONFIG_XEN_SYMS
+ { "xensyms", &xensyms_ops, S_IRUSR},
+#endif
+ {""},
+ };
+
+ return simple_fill_super(sb, XENFS_SUPER_MAGIC,
+ xen_initial_domain() ? xenfs_init_files : xenfs_files);
+}
+
+static struct dentry *xenfs_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *data)
+{
+ return mount_single(fs_type, flags, data, xenfs_fill_super);
+}
+
+static struct file_system_type xenfs_type = {
+ .owner = THIS_MODULE,
+ .name = "xenfs",
+ .mount = xenfs_mount,
+ .kill_sb = kill_litter_super,
+};
+MODULE_ALIAS_FS("xenfs");
+
+static int __init xenfs_init(void)
+{
+ if (xen_domain())
+ return register_filesystem(&xenfs_type);
+
+ return 0;
+}
+
+static void __exit xenfs_exit(void)
+{
+ if (xen_domain())
+ unregister_filesystem(&xenfs_type);
+}
+
+module_init(xenfs_init);
+module_exit(xenfs_exit);
+