1 /* 2 * xenfs.c - a filesystem for passing info between the a domain and 3 * the hypervisor. 4 * 5 * 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem 6 * and /proc/xen compatibility mount point. 7 * Turned xenfs into a loadable module. 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/errno.h> 12 #include <linux/module.h> 13 #include <linux/fs.h> 14 #include <linux/magic.h> 15 16 #include "xenfs.h" 17 18 #include <asm/xen/hypervisor.h> 19 20 MODULE_DESCRIPTION("Xen filesystem"); 21 MODULE_LICENSE("GPL"); 22 23 static int xenfs_fill_super(struct super_block *sb, void *data, int silent) 24 { 25 static struct tree_descr xenfs_files[] = { 26 [2] = {"xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR}, 27 {""}, 28 }; 29 30 return simple_fill_super(sb, XENFS_SUPER_MAGIC, xenfs_files); 31 } 32 33 static int xenfs_get_sb(struct file_system_type *fs_type, 34 int flags, const char *dev_name, 35 void *data, struct vfsmount *mnt) 36 { 37 return get_sb_single(fs_type, flags, data, xenfs_fill_super, mnt); 38 } 39 40 static struct file_system_type xenfs_type = { 41 .owner = THIS_MODULE, 42 .name = "xenfs", 43 .get_sb = xenfs_get_sb, 44 .kill_sb = kill_litter_super, 45 }; 46 47 static int __init xenfs_init(void) 48 { 49 if (xen_pv_domain()) 50 return register_filesystem(&xenfs_type); 51 52 printk(KERN_INFO "XENFS: not registering filesystem on non-xen platform\n"); 53 return 0; 54 } 55 56 static void __exit xenfs_exit(void) 57 { 58 if (xen_pv_domain()) 59 unregister_filesystem(&xenfs_type); 60 } 61 62 module_init(xenfs_init); 63 module_exit(xenfs_exit); 64 65