From 648a85038f7673d028cd9d345db9192d1cb62915 Mon Sep 17 00:00:00 2001
From: Stefano Stabellini
Date: Thu, 28 Jul 2022 16:50:31 -0700
Subject: Add a DOMU_ENHANCED config option

The new option allows to disable "xen,enhanced" for individual domUs.
Useful to boot old unpatched kernels.

Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
---
 README.md                | 4 ++++
 scripts/uboot-script-gen | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 07ad432..bd9dac9 100644
--- a/README.md
+++ b/README.md
@@ -177,6 +177,10 @@ Where:
   If set to 1, the VM is direct mapped. The default is 1.
   This is only applicable when DOMU_STATIC_MEM is specified.
 
+- DOMU_ENHANCED[number] can be set to 1 or 0, default is 1 when Dom0 is
+  present. If set to 1, the VM can use PV drivers. Older Linux kernels
+  might break.
+
 - LINUX is optional but specifies the Linux kernel for when Xen is NOT
   used.  To enable this set any LINUX\_\* variables and do NOT set the
   XEN variable.
diff --git a/scripts/uboot-script-gen b/scripts/uboot-script-gen
index 995798d..18c0ce1 100755
--- a/scripts/uboot-script-gen
+++ b/scripts/uboot-script-gen
@@ -222,7 +222,7 @@ function xen_device_tree_editing()
             dt_set "/chosen/domU$i" "direct-map" "bool" "${DOMU_DIRECT_MAP[$i]}"
         fi
         dt_set "/chosen/domU$i" "vpl011" "hex" "0x1"
-        if test "$DOM0_KERNEL"
+        if [[ "${DOMU_ENHANCED[$i]}" == 1 || ("$DOM0_KERNEL" && "${DOMU_ENHANCED[$i]}" != 0) ]]
         then
             dt_set "/chosen/domU$i" "xen,enhanced" "str" "enabled"
         fi
-- 
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