[RFC PATCH 04/14] 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              | 39 +++++++++
 .../ConfidentialMigrationDxe.c                | 83 +++++++++++++++++++
 5 files changed, 129 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 4450d78b91..402c3b61fa 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -324,6 +324,11 @@
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId|0|UINT16|0x1b
   gUefiOvmfPkgTokenSpaceGuid.PcdQemuSmbiosValidated|FALSE|BOOLEAN|0x21
 
+  ## Set via FW_CFG to enable confidentialmigration as source or target.
+  #
+  gUefiOvmfPkgTokenSpaceGuid.PcdIsConfidentialMigrationTarget|FALSE|BOOLEAN|0x46
+  gUefiOvmfPkgTokenSpaceGuid.PcdStartConfidentialMigrationHandler|FALSE|BOOLEAN|0x47
+
   ## The IO port aperture shared by all PCI root bridges.
   #
   gUefiOvmfPkgTokenSpaceGuid.PcdPciIoBase|0x0|UINT64|0x22
diff --git a/OvmfPkg/AmdSev/AmdSevX64.dsc b/OvmfPkg/AmdSev/AmdSevX64.dsc
index ca21fd6e5f..fa68143663 100644
--- a/OvmfPkg/AmdSev/AmdSevX64.dsc
+++ b/OvmfPkg/AmdSev/AmdSevX64.dsc
@@ -787,6 +787,7 @@
 !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 c0098502aa..6ef6dc89f2 100644
--- a/OvmfPkg/AmdSev/AmdSevX64.fdf
+++ b/OvmfPkg/AmdSev/AmdSevX64.fdf
@@ -273,6 +273,7 @@ INF  MdeModulePkg/Universal/Disk/UdfDxe/UdfDxe.inf
 INF  OvmfPkg/LinuxInitrdDynamicShellCommand/LinuxInitrdDynamicShellCommand.inf
 !endif
 INF OvmfPkg/AmdSev/SecretDxe/SecretDxe.inf
+INF OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
 INF  OvmfPkg/AmdSev/Grub/Grub.inf
 !if $(BUILD_SHELL) == TRUE
 INF  ShellPkg/Application/Shell/Shell.inf
diff --git a/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
new file mode 100644
index 0000000000..a4906a2451
--- /dev/null
+++ b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
@@ -0,0 +1,39 @@
+## @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_DRIVER
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = LaunchMigrationHandler
+
+[Sources]
+  ConfidentialMigrationDxe.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+  UefiCpuPkg/UefiCpuPkg.dec
+
+[LibraryClasses]
+  MemoryAllocationLib
+  DebugLib
+  UefiBootServicesTableLib
+  MpInitLib
+  UefiDriverEntryPoint
+
+[Protocols]
+  gEfiMpServiceProtocolGuid
+
+[Pcd]
+  gUefiOvmfPkgTokenSpaceGuid.PcdIsConfidentialMigrationTarget
+  gUefiOvmfPkgTokenSpaceGuid.PcdStartConfidentialMigrationHandler
+
+[Depex]
+  gEfiMpServiceProtocolGuid
diff --git a/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c
new file mode 100644
index 0000000000..6d9fe7043b
--- /dev/null
+++ b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c
@@ -0,0 +1,83 @@
+/** @file
+  In-guest support for confidential migration
+
+  Copyright (C) 2021 IBM Coporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+#include <Library/UefiLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiRuntimeServicesTableLib.h>
+#include <Library/DebugLib.h>
+#include <Protocol/MpService.h>
+
+UINTN MigrationHandlerCpuIndex;
+
+VOID
+EFIAPI
+MigrationHandlerMain (
+  IN OUT VOID *Buffer
+  )
+{
+  DebugPrint (DEBUG_INFO,"MIGRATION Handler Started\n");
+}
+
+EFI_STATUS
+EFIAPI
+LaunchMigrationHandler (
+  IN EFI_HANDLE           ImageHandle,
+  IN EFI_SYSTEM_TABLE     *SystemTable
+  )
+{
+  EFI_MP_SERVICES_PROTOCOL      *MpProto;
+  EFI_PROCESSOR_INFORMATION     Tcb;
+  EFI_STATUS                    Status;
+  UINTN                         NumProc;
+  UINTN                         NumEnabled;
+
+  gST = SystemTable;
+  gBS = gST->BootServices;
+  gRT = gST->RuntimeServices;
+
+  Status = EFI_NOT_STARTED;
+
+  if (!PcdGetBool(PcdStartConfidentialMigrationHandler)) {
+    return 0;
+  }
+
+  //
+  // Use the MP Service protocol to start Migration Handler on AP
+  //
+  gBS->LocateProtocol (&gEfiMpServiceProtocolGuid, NULL, (void**)&MpProto);
+  MpProto->GetNumberOfProcessors (MpProto, &NumProc, &NumEnabled);
+  if (NumProc < 2) {
+    DebugPrint (DEBUG_ERROR,"Only one vCPU enabled. Please start an extra for the MH.\n");
+    return 0;
+  }
+
+  MigrationHandlerCpuIndex = NumProc - 1;
+
+  EFI_EVENT Event;
+  MpProto->GetProcessorInfo (MpProto, MigrationHandlerCpuIndex, &Tcb);
+  if (Tcb.StatusFlag != 7) {
+    gBS->CreateEvent (EVT_TIMER, TPL_NOTIFY, NULL, NULL, &Event);
+
+    Status = MpProto->StartupThisAP(MpProto, MigrationHandlerMain, 1, Event,
+                                    0, MpProto, NULL);
+  }
+  if (Status != EFI_SUCCESS) {
+    DebugPrint (DEBUG_ERROR,"Failed to start Migration Handler\n");
+    return 0;
+  }
+
+  //
+  // If we are the target, wait for incoming migration. Otherwise,
+  // procede with the boot.
+  //
+  if (PcdGetBool(PcdIsConfidentialMigrationTarget)) {
+    DebugPrint (DEBUG_INFO,"Waiting for incoming confidential migration.\n");
+    DisableInterrupts ();
+    CpuDeadLoop ();
+  }
+
+  return 0;
+}
-- 
2.20.1