OvmfPkg: Add AmdSevDxe driver
[mirror_edk2.git] / OvmfPkg / AmdSevDxe / AmdSevDxe.c
CommitLineData
24e4ad75
BS
1/** @file\r
2\r
3 AMD Sev Dxe driver. This driver is dispatched early in DXE, due to being list\r
4 in APRIORI. It clears C-bit from MMIO and NonExistent Memory space when SEV is\r
5 enabled.\r
6\r
7 Copyright (c) 2017, AMD Inc. All rights reserved.<BR>\r
8\r
9 This program and the accompanying materials\r
10 are licensed and made available under the terms and conditions of the BSD\r
11 License which accompanies this distribution. The full text of the license may\r
12 be found at http://opensource.org/licenses/bsd-license.php\r
13\r
14 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
15 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
16\r
17**/\r
18\r
19#include <PiDxe.h>\r
20\r
21#include <Library/BaseLib.h>\r
22#include <Library/DebugLib.h>\r
23#include <Library/BaseMemoryLib.h>\r
24#include <Library/MemoryAllocationLib.h>\r
25#include <Library/UefiBootServicesTableLib.h>\r
26#include <Library/DxeServicesTableLib.h>\r
27#include <Library/MemEncryptSevLib.h>\r
28\r
29EFI_STATUS\r
30EFIAPI\r
31AmdSevDxeEntryPoint (\r
32 IN EFI_HANDLE ImageHandle,\r
33 IN EFI_SYSTEM_TABLE *SystemTable\r
34 )\r
35{\r
36 EFI_STATUS Status;\r
37 EFI_GCD_MEMORY_SPACE_DESCRIPTOR *AllDescMap;\r
38 UINTN NumEntries;\r
39 UINTN Index;\r
40\r
41 //\r
42 // Do nothing when SEV is not enabled\r
43 //\r
44 if (!MemEncryptSevIsEnabled ()) {\r
45 return EFI_UNSUPPORTED;\r
46 }\r
47\r
48 //\r
49 // Iterate through the GCD map and clear the C-bit from MMIO and NonExistent\r
50 // memory space. The NonExistent memory space will be used for mapping the MMIO\r
51 // space added later (eg PciRootBridge). By clearing both known MMIO and\r
52 // NonExistent memory space can gurantee that current and furture MMIO adds\r
53 // will have C-bit cleared.\r
54 //\r
55 Status = gDS->GetMemorySpaceMap (&NumEntries, &AllDescMap);\r
56 if (!EFI_ERROR (Status)) {\r
57 for (Index = 0; Index < NumEntries; Index++) {\r
58 CONST EFI_GCD_MEMORY_SPACE_DESCRIPTOR *Desc;\r
59\r
60 Desc = &AllDescMap[Index];\r
61 if (Desc->GcdMemoryType == EfiGcdMemoryTypeMemoryMappedIo ||\r
62 Desc->GcdMemoryType == EfiGcdMemoryTypeNonExistent) {\r
63 Status = MemEncryptSevClearPageEncMask (0,\r
64 Desc->BaseAddress,\r
65 EFI_SIZE_TO_PAGES(Desc->Length),\r
66 FALSE);\r
67 ASSERT_EFI_ERROR (Status);\r
68 }\r
69 }\r
70\r
71 FreePool (AllDescMap);\r
72 }\r
73\r
74 return EFI_SUCCESS;\r
75}\r