[XEN][PATCH v10 05/20] xen/arm: Add CONFIG_OVERLAY_DTB

[Vikram Garhwal <vikram.garhwal@xxxxxxx>]

Introduce a config option where the user can enable support for adding/removing
device tree nodes using a device tree binary overlay.

Update SUPPORT.md and CHANGELOG.md to state the Device Tree Overlays support for
Arm.

Signed-off-by: Vikram Garhwal <vikram.garhwal@xxxxxxx>
Acked-by: Henry Wang <Henry.Wang@xxxxxxx>
Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>

---
Changes from v9:
    Fix style.
Changes from v7:
    Add this feature as "experimental support" in CHANGELOG.md
---
---
 CHANGELOG.md         | 3 ++-
 SUPPORT.md           | 6 ++++++
 xen/arch/arm/Kconfig | 5 +++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7d7e0590f8..f6f4c351c9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,7 +24,8 @@ The format is based on [Keep a 
Changelog](https://keepachangelog.com/en/1.0.0/)
  - xl/libxl can customize SMBIOS strings for HVM guests.
  - Add support for AVX512-FP16 on x86.
  - On Arm, Xen supports guests running SVE/SVE2 instructions. (Tech Preview)
-
+ - On Arm, experimental support for dynamic addition/removal of Xen device tree
+   nodes using a device tree overlay binary (.dtbo).
 
 ## 
[4.17.0](https://xenbits.xen.org/gitweb/?p=xen.git;a=shortlog;h=RELEASE-4.17.0) 
- 2022-12-12
 
diff --git a/SUPPORT.md b/SUPPORT.md
index 35a6249e03..8ec272eabd 100644
--- a/SUPPORT.md
+++ b/SUPPORT.md
@@ -844,6 +844,12 @@ No support for QEMU backends in a 16K or 64K domain.
 
     Status: Supported
 
+### Device Tree Overlays
+
+Add/Remove device tree nodes using a device tree overlay binary (.dtbo).
+
+    Status, ARM: Experimental
+
 ### ARM: Guest ACPI support
 
     Status: Supported
diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index fd57a82dd2..02c4796438 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -92,6 +92,11 @@ config HAS_ITS
         bool "GICv3 ITS MSI controller support (UNSUPPORTED)" if UNSUPPORTED
         depends on GICV3 && !NEW_VGIC && !ARM_32
 
+config OVERLAY_DTB
+       bool "DTB overlay support (UNSUPPORTED)" if UNSUPPORTED
+       help
+         Dynamic addition/removal of Xen device tree nodes using a dtbo.
+
 config HVM
         def_bool y
 
-- 
2.17.1