ArmVirtPkg: Add PlatformHasAcpiDtDxe for Cloud Hypervisor

The ArmVirtPkg\PlatformHasAcpiDtDxe implementation is not common
and is specific for Qemu. So add a Cloud Hypervisor specific
version that decides whether the firmware should expose an ACPI
based or a Device Tree based hardware description to an operating
system.

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Sami Mujawar <sami.mujawar@arm.com>

Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>

ArmVirtPkg/CloudHvPlatformHasAcpiDtDxe/CloudHvHasAcpiDtDxe.c

@@ -0,0 +1,79 @@
+/** @file
+  Decide whether the firmware should expose an ACPI- and/or a Device Tree-based
+  hardware description to the operating system.
+
+  Copyright (c) 2021, Arm Limited. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Guid/PlatformHasAcpi.h>
+#include <Guid/PlatformHasDeviceTree.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/PcdLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+
+/** Entry point for the Cloud Hypervisor PlatformHasAcpiDtDxe.
+
+  @param [in]  ImageHandle  Handle for this image.
+  @param [in]  SystemTable  Pointer to the EFI system table.
+
+  @return EFI_SUCCESS             If ACPI or Device Tree based hardware
+                                  description protocol was installed.
+  @return EFI_INVALID_PARAMETER   A parameter was invalid.
+  @return EFI_OUT_OF_RESOURCES    Insufficient resources exist to complete
+                                  the request.
+**/
+EFI_STATUS
+EFIAPI
+PlatformHasAcpiDt (
+  IN EFI_HANDLE       ImageHandle,
+  IN EFI_SYSTEM_TABLE *SystemTable
+  )
+{
+  EFI_STATUS           Status;
+
+  //
+  // If we fail to install any of the necessary protocols below, the OS will be
+  // unbootable anyway (due to lacking hardware description), so tolerate no
+  // errors here.
+  //
+  if (MAX_UINTN == MAX_UINT64 &&
+      !PcdGetBool (PcdForceNoAcpi)) {
+    Status = gBS->InstallProtocolInterface (
+                    &ImageHandle,
+                    &gEdkiiPlatformHasAcpiGuid,
+                    EFI_NATIVE_INTERFACE,
+                    NULL
+                    );
+    if (EFI_ERROR (Status)) {
+      goto Failed;
+    }
+
+    return Status;
+  }
+
+  //
+  // Expose the Device Tree otherwise.
+  //
+  Status = gBS->InstallProtocolInterface (
+                  &ImageHandle,
+                  &gEdkiiPlatformHasDeviceTreeGuid,
+                  EFI_NATIVE_INTERFACE,
+                  NULL
+                  );
+  if (EFI_ERROR (Status)) {
+    goto Failed;
+  }
+
+  return Status;
+
+Failed:
+  ASSERT_EFI_ERROR (Status);
+  CpuDeadLoop ();
+  //
+  // Keep compilers happy.
+  //
+  return Status;
+}

ArmVirtPkg/CloudHvPlatformHasAcpiDtDxe/CloudHvHasAcpiDtDxe.inf

@@ -0,0 +1,42 @@
+## @file
+# Decide whether the firmware should expose an ACPI- and/or a Device Tree-based
+# hardware description to the operating system.
+#
+# Copyright (c) 2021, Arm Limited. All rights reserved.<BR>
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001B
+  BASE_NAME                      = CloudHvPlatformHasAcpiDtDxe
+  FILE_GUID                      = 71fe72f9-6dc1-199d-5054-13b4200ee88d
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = PlatformHasAcpiDt
+
+[Sources]
+  CloudHvHasAcpiDtDxe.c
+
+[Packages]
+  ArmVirtPkg/ArmVirtPkg.dec
+  EmbeddedPkg/EmbeddedPkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  PcdLib
+  UefiBootServicesTableLib
+  UefiDriverEntryPoint
+
+[Guids]
+  gEdkiiPlatformHasAcpiGuid       ## SOMETIMES_PRODUCES ## PROTOCOL
+  gEdkiiPlatformHasDeviceTreeGuid ## SOMETIMES_PRODUCES ## PROTOCOL
+
+[Pcd]
+  gArmVirtTokenSpaceGuid.PcdForceNoAcpi
+
+[Depex]
+  gEfiVariableArchProtocolGuid