[xen staging] xen: Allow EXPERT mode to be selected from the menuconfig directly

[patchbot@xxxxxxx]

commit d155e4aef35cd9c03f6db7030a956f83f33a1e99
Author:     Julien Grall <jgrall@xxxxxxxxxx>
AuthorDate: Thu Apr 30 15:25:48 2020 +0100
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Thu May 14 10:20:04 2020 +0100

    xen: Allow EXPERT mode to be selected from the menuconfig directly
    
    EXPERT mode is currently used to gate any options that are in technical
    preview or not security supported. At the moment, this is selected by
    adding XEN_CONFIG_EXPERT=y on the make command line, or to the
    (currently undocumented) top-level .config file.
    
    This makes the option very unintuitive to use: If the user forgets to
    add the option when (re)building or when using menuconfig, then
    xen/.config will be silently rewritten, leading to behavior which is
    very difficult to diagnose.  Adding XEN_CONFIG_EXPERT=y to the
    top-level .config is not obvious behavior, particularly as the file is
    undocumented.
    
    A lot of the options behind EXPERT would benefit from being more
    accessible so users can experiment with them and voice any concerns
    before they are fully supported.
    
    To make this option more discoverable and consistent to use, make it
    possible to select it from the menuconfig.
    
    This doesn't change the fact a Xen with EXPERT mode selected will not
    be security supported.
    
    Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
    Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxx>
    Acked-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---
 xen/Kconfig  | 10 +++++++++-
 xen/Makefile |  1 -
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/xen/Kconfig b/xen/Kconfig
index 120b5f4129..34c318bfa2 100644
--- a/xen/Kconfig
+++ b/xen/Kconfig
@@ -35,7 +35,15 @@ config DEFCONFIG_LIST
        default ARCH_DEFCONFIG
 
 config EXPERT
-       def_bool y if "$(XEN_CONFIG_EXPERT)" = "y"
+       bool "Configure standard Xen features (expert users)"
+       help
+         This option allows certain base Xen options and settings
+         to be disabled or tweaked. This is for specialized environments
+         which can tolerate a "non-standard" Xen.
+         Only use this if you really know what you are doing.
+         Xen binaries built with this option enabled are not security
+         supported.
+       default n
 
 config LTO
        bool "Link Time Optimisation"
diff --git a/xen/Makefile b/xen/Makefile
index 2b1dacb497..286f374b54 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -11,7 +11,6 @@ export XEN_DOMAIN     ?= $(shell ([ -x /bin/dnsdomainname ] 
&& /bin/dnsdomainname) |
 export XEN_BUILD_DATE  ?= $(shell LC_ALL=C date)
 export XEN_BUILD_TIME  ?= $(shell LC_ALL=C date +%T)
 export XEN_BUILD_HOST  ?= $(shell hostname)
-export XEN_CONFIG_EXPERT ?= n
 
 # Best effort attempt to find a python interpreter, defaulting to Python 3 if
 # available.  Fall back to just `python` if `which` is nowhere to be found.
--
generated by git-patchbot for /home/xen/git/xen.git#staging