xen: add xenfs to allow usermode <-> Xen interaction
The xenfs filesystem exports various interfaces to usermode. Initially
this exports a file to allow usermode to interact with xenbus/xenstore.
Traditionally this appeared in /proc/xen. Rather than extending procfs,
this patch adds a backward-compat mountpoint on /proc/xen, and provides
a xenfs filesystem which can be mounted there.
Signed-off-by: Alex Zeffertt <alex.zeffertt@eu.citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 4b75a16..526187c 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -17,3 +17,27 @@
is not accidentally visible to other domains. Is it more
secure, but slightly less efficient.
If in doubt, say yes.
+
+config XENFS
+ tristate "Xen filesystem"
+ depends on XEN
+ default y
+ help
+ The xen filesystem provides a way for domains to share
+ information with each other and with the hypervisor.
+ For example, by reading and writing the "xenbus" file, guests
+ may pass arbitrary information to the initial domain.
+ If in doubt, say yes.
+
+config XEN_COMPAT_XENFS
+ bool "Create compatibility mount point /proc/xen"
+ depends on XENFS
+ default y
+ help
+ The old xenstore userspace tools expect to find "xenbus"
+ under /proc/xen, but "xenbus" is now found at the root of the
+ xenfs filesystem. Selecting this causes the kernel to create
+ the compatibilty mount point /proc/xen if it is running on
+ a xen platform.
+ If in doubt, say yes.
+