xen/gntdev: allow usermode to map granted pages

The gntdev driver allows usermode to map granted pages from other
domains.  This is typically used to implement a Xen backend driver
in user mode.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 6e6180ccd726..bd3095f0dff2 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -62,6 +62,13 @@ config XEN_SYS_HYPERVISOR
          virtual environment, /sys/hypervisor will still be present,
          but will have no xen contents.
 
+config XEN_GNTDEV
+        tristate "userspace grant access device driver"
+        depends on XEN
+        select MMU_NOTIFIER
+        help
+          Allows userspace processes to use grants.
+
 config XEN_PLATFORM_PCI
         tristate "xen platform pci device driver"
         depends on XEN_PVHVM