[RFC PATCH 1/9] OvmfPkg/AmdSev: Base for Confidential Migration Handler

["Tobin Feldman-Fitzthum" <tobin@linux.ibm.com>]

Base enablement of DXE driver that supports confidential migration.

Signed-off-by: Tobin Feldman-Fitzthum <tobin@linux.ibm.com>
---
 OvmfPkg/OvmfPkg.dec                           |  5 ++
 OvmfPkg/AmdSev/AmdSevX64.dsc                  |  1 +
 OvmfPkg/AmdSev/AmdSevX64.fdf                  |  1 +
 .../ConfidentialMigrationDxe.inf              | 34 ++++++++++++
 .../ConfidentialMigrationDxe.c                | 53 +++++++++++++++++++
 5 files changed, 94 insertions(+)
 create mode 100644 OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
 create mode 100644 OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c

diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 3978852557..cfc645619d 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -370,6 +370,11 @@
   #  instance in PiSmmCpuDxeSmm, and CpuHotplugSmm.
   gUefiOvmfPkgTokenSpaceGuid.PcdCpuHotEjectDataAddress|0|UINT64|0x46
 
+  ## Set via FW_CFG to enable confidential migration as source or target.
+  #
+  gUefiOvmfPkgTokenSpaceGuid.PcdIsConfidentialMigrationTarget|FALSE|BOOLEAN|0x49
+  gUefiOvmfPkgTokenSpaceGuid.PcdStartConfidentialMigrationHandler|FALSE|BOOLEAN|0x4a
+
 [PcdsFeatureFlag]
   gUefiOvmfPkgTokenSpaceGuid.PcdQemuBootOrderPciTranslation|TRUE|BOOLEAN|0x1c
   gUefiOvmfPkgTokenSpaceGuid.PcdQemuBootOrderMmioTranslation|FALSE|BOOLEAN|0x1d
diff --git a/OvmfPkg/AmdSev/AmdSevX64.dsc b/OvmfPkg/AmdSev/AmdSevX64.dsc
index e6cd10b759..982ecaf70e 100644
--- a/OvmfPkg/AmdSev/AmdSevX64.dsc
+++ b/OvmfPkg/AmdSev/AmdSevX64.dsc
@@ -790,6 +790,7 @@
 !endif
   OvmfPkg/AmdSev/SecretDxe/SecretDxe.inf
   OvmfPkg/AmdSev/Grub/Grub.inf
+  OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
 !if $(BUILD_SHELL) == TRUE
   ShellPkg/Application/Shell/Shell.inf {
     <LibraryClasses>
diff --git a/OvmfPkg/AmdSev/AmdSevX64.fdf b/OvmfPkg/AmdSev/AmdSevX64.fdf
index 0a89749700..9bf17b8d51 100644
--- a/OvmfPkg/AmdSev/AmdSevX64.fdf
+++ b/OvmfPkg/AmdSev/AmdSevX64.fdf
@@ -274,6 +274,7 @@ INF  OvmfPkg/LinuxInitrdDynamicShellCommand/LinuxInitrdDynamicShellCommand.inf
 !endif
 INF OvmfPkg/AmdSev/SecretDxe/SecretDxe.inf
 INF  OvmfPkg/AmdSev/Grub/Grub.inf
+INF OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
 !if $(BUILD_SHELL) == TRUE
 INF  ShellPkg/Application/Shell/Shell.inf
 !endif
diff --git a/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
new file mode 100644
index 0000000000..6e3fa7e51c
--- /dev/null
+++ b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
@@ -0,0 +1,34 @@
+## @file
+#
+#  Copyright (C) 2021 IBM Corporation.
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = ConfidentialMigration
+  FILE_GUID                      = 5c2978f4-f175-434b-9e6c-9b03bd7e346f
+  MODULE_TYPE                    = DXE_RUNTIME_DRIVER
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = SetupMigrationHandler
+
+[Sources]
+  ConfidentialMigrationDxe.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  DebugLib
+  MemoryAllocationLib
+  UefiDriverEntryPoint
+  UefiLib
+
+[Pcd]
+  gUefiOvmfPkgTokenSpaceGuid.PcdIsConfidentialMigrationTarget
+  gUefiOvmfPkgTokenSpaceGuid.PcdStartConfidentialMigrationHandler
+
+[Depex]
+  TRUE
diff --git a/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c
new file mode 100644
index 0000000000..f0dfbd279e
--- /dev/null
+++ b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c
@@ -0,0 +1,53 @@
+/** @file
+  In-guest support for confidential migration
+
+  Copyright (C) 2021 IBM Coporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Library/DebugLib.h>
+#include <Library/UefiLib.h>
+
+VOID
+EFIAPI
+MigrationHandlerMain ()
+{
+  DebugPrint (DEBUG_INFO,"Migration Handler Started\n");
+
+}
+
+/**
+SetupMigrationHandler runs in the firmware of the main VM to setup
+regions of memory that the Migration Handler can use when executing
+in the mirror VM.
+
+**/
+EFI_STATUS
+EFIAPI
+SetupMigrationHandler (
+  IN EFI_HANDLE           ImageHandle,
+  IN EFI_SYSTEM_TABLE     *SystemTable
+  )
+{
+
+  if (!PcdGetBool(PcdStartConfidentialMigrationHandler)) {
+    return 0;
+  }
+
+  //
+  // If VM is migration target, wait until hypervisor modifies CPU state
+  // and restarts execution.
+  //
+  if (PcdGetBool(PcdIsConfidentialMigrationTarget)) {
+    DebugPrint (DEBUG_INFO,"Waiting for incoming confidential migration.\n");
+
+    while (1) {
+      CpuPause ();
+    }
+  }
+
+  //
+  // If VM is migration source, continue with boot.
+  //
+  return 0;
+}
-- 
2.20.1