[XEN][PATCH v7 05/19] 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>

---
Changes from v6:
    Add CHANGELOG and SUPPORT.md entries.
---
 CHANGELOG.md         | 2 ++
 SUPPORT.md           | 6 ++++++
 xen/arch/arm/Kconfig | 5 +++++
 3 files changed, 13 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5bfd3aa5c0..a137fce576 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,8 @@ The format is based on [Keep a 
Changelog](https://keepachangelog.com/en/1.0.0/)
    - Bus-lock detection, used by Xen to mitigate (by rate-limiting) the system
      wide impact of a guest misusing atomic instructions.
  - xl/libxl can customize SMBIOS strings for HVM guests.
+ - On Arm, 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 6dbed9d5d0..6b27d43cc6 100644
--- a/SUPPORT.md
+++ b/SUPPORT.md
@@ -832,6 +832,12 @@ 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 239d3aed3c..1fe3d698a5 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -53,6 +53,11 @@ 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