OvmfPkg: Add AmdSevDxe driver

[mirror_edk2.git] / OvmfPkg / AmdSevDxe / AmdSevDxe.c

diff --git a/OvmfPkg/AmdSevDxe/AmdSevDxe.c b/OvmfPkg/AmdSevDxe/AmdSevDxe.c
new file mode 100644 (file)
index 0000000..e472096
--- /dev/null
+++ b/OvmfPkg/AmdSevDxe/AmdSevDxe.c
@@ -0,0 +1,75 @@
+/** @file\r
+\r
+  AMD Sev Dxe driver. This driver is dispatched early in DXE, due to being list\r
+  in APRIORI. It clears C-bit from MMIO and NonExistent Memory space when SEV is\r
+  enabled.\r
+\r
+  Copyright (c) 2017, AMD Inc. All rights reserved.<BR>\r
+\r
+  This program and the accompanying materials\r
+  are licensed and made available under the terms and conditions of the BSD\r
+  License which accompanies this distribution.  The full text of the license may\r
+  be found at http://opensource.org/licenses/bsd-license.php\r
+\r
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+\r
+**/\r
+\r
+#include <PiDxe.h>\r
+\r
+#include <Library/BaseLib.h>\r
+#include <Library/DebugLib.h>\r
+#include <Library/BaseMemoryLib.h>\r
+#include <Library/MemoryAllocationLib.h>\r
+#include <Library/UefiBootServicesTableLib.h>\r
+#include <Library/DxeServicesTableLib.h>\r
+#include <Library/MemEncryptSevLib.h>\r
+\r
+EFI_STATUS\r
+EFIAPI\r
+AmdSevDxeEntryPoint (\r
+  IN EFI_HANDLE         ImageHandle,\r
+  IN EFI_SYSTEM_TABLE   *SystemTable\r
+  )\r
+{\r
+  EFI_STATUS                       Status;\r
+  EFI_GCD_MEMORY_SPACE_DESCRIPTOR  *AllDescMap;\r
+  UINTN                            NumEntries;\r
+  UINTN                            Index;\r
+\r
+  //\r
+  // Do nothing when SEV is not enabled\r
+  //\r
+  if (!MemEncryptSevIsEnabled ()) {\r
+    return EFI_UNSUPPORTED;\r
+  }\r
+\r
+  //\r
+  // Iterate through the GCD map and clear the C-bit from MMIO and NonExistent\r
+  // memory space. The NonExistent memory space will be used for mapping the MMIO\r
+  // space added later (eg PciRootBridge). By clearing both known MMIO and\r
+  // NonExistent memory space can gurantee that current and furture MMIO adds\r
+  // will have C-bit cleared.\r
+  //\r
+  Status = gDS->GetMemorySpaceMap (&NumEntries, &AllDescMap);\r
+  if (!EFI_ERROR (Status)) {\r
+    for (Index = 0; Index < NumEntries; Index++) {\r
+      CONST EFI_GCD_MEMORY_SPACE_DESCRIPTOR *Desc;\r
+\r
+      Desc = &AllDescMap[Index];\r
+      if (Desc->GcdMemoryType == EfiGcdMemoryTypeMemoryMappedIo ||\r
+          Desc->GcdMemoryType == EfiGcdMemoryTypeNonExistent) {\r
+        Status = MemEncryptSevClearPageEncMask (0,\r
+                                                Desc->BaseAddress,\r
+                                                EFI_SIZE_TO_PAGES(Desc->Length),\r
+                                                FALSE);\r
+        ASSERT_EFI_ERROR (Status);\r
+      }\r
+    }\r
+\r
+    FreePool (AllDescMap);\r
+  }\r
+\r
+  return EFI_SUCCESS;\r
+}\r