[PATCH v2] ArmVirtPkg AARCH64: enable NX memory protection for all platforms

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

This sets the recently introduced PCD PcdDxeNxMemoryProtectionPolicy to
a value that protects all memory regions except code regions against
inadvertent execution.

Note that this does not [yet] protect EfiLoaderData regions, due to
compatibility issues with shim and GRUB.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
v2: leave EfiLoaderData executable for the time being

 ArmVirtPkg/ArmVirt.dsc.inc | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/ArmVirtPkg/ArmVirt.dsc.inc b/ArmVirtPkg/ArmVirt.dsc.inc
index 2b0a44e14d24..a91b27f13cf2 100644
--- a/ArmVirtPkg/ArmVirt.dsc.inc
+++ b/ArmVirtPkg/ArmVirt.dsc.inc
@@ -383,6 +383,13 @@ [PcdsFixedAtBuild.AARCH64]
   #
   gEfiMdeModulePkgTokenSpaceGuid.PcdImageProtectionPolicy|0x3
 
+  #
+  # Enable NX memory protection for all non-code regions, including OEM and OS
+  # reserved ones, with the exception of LoaderData regions, of which OS loaders
+  # (i.e., GRUB) may assume that its contents are executable.
+  #
+  gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy|0xC000000000007FD1
+
 [Components.common]
   #
   # Networking stack
-- 
2.7.4