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5267c89b LE |
1 | /** @file\r |
2 | \r | |
3 | Utility functions for serializing (persistently storing) and deserializing\r | |
4 | OVMF's platform configuration.\r | |
5 | \r | |
6 | Copyright (C) 2014, Red Hat, Inc.\r | |
7 | \r | |
b26f0cf9 | 8 | SPDX-License-Identifier: BSD-2-Clause-Patent\r |
5267c89b LE |
9 | \r |
10 | **/\r | |
11 | \r | |
12 | #include <Library/BaseMemoryLib.h>\r | |
13 | #include <Library/DebugLib.h>\r | |
14 | #include <Library/MemoryAllocationLib.h>\r | |
15 | #include <Library/UefiLib.h>\r | |
16 | #include <Library/UefiRuntimeServicesTableLib.h>\r | |
17 | #include <Guid/OvmfPlatformConfig.h>\r | |
18 | \r | |
19 | #include "PlatformConfig.h"\r | |
20 | \r | |
21 | //\r | |
22 | // Name of the UEFI variable that we use for persistent storage.\r | |
23 | //\r | |
ac0a286f | 24 | STATIC CHAR16 mVariableName[] = L"PlatformConfig";\r |
5267c89b LE |
25 | \r |
26 | /**\r | |
27 | Serialize and persistently save platform configuration.\r | |
28 | \r | |
29 | @param[in] PlatformConfig The platform configuration to serialize and save.\r | |
30 | \r | |
31 | @return Status codes returned by gRT->SetVariable().\r | |
32 | **/\r | |
33 | EFI_STATUS\r | |
34 | EFIAPI\r | |
35 | PlatformConfigSave (\r | |
ac0a286f | 36 | IN PLATFORM_CONFIG *PlatformConfig\r |
5267c89b LE |
37 | )\r |
38 | {\r | |
ac0a286f | 39 | EFI_STATUS Status;\r |
5267c89b LE |
40 | \r |
41 | //\r | |
42 | // We could implement any kind of translation here, as part of serialization.\r | |
43 | // For example, we could expose the platform configuration in separate\r | |
44 | // variables with human-readable contents, allowing other tools to access\r | |
45 | // them more easily. For now, just save a binary dump.\r | |
46 | //\r | |
ac0a286f MK |
47 | Status = gRT->SetVariable (\r |
48 | mVariableName,\r | |
49 | &gOvmfPlatformConfigGuid,\r | |
5267c89b | 50 | EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS |\r |
ac0a286f MK |
51 | EFI_VARIABLE_RUNTIME_ACCESS,\r |
52 | sizeof *PlatformConfig,\r | |
53 | PlatformConfig\r | |
54 | );\r | |
5267c89b LE |
55 | return Status;\r |
56 | }\r | |
57 | \r | |
5267c89b LE |
58 | /**\r |
59 | Load and deserialize platform configuration.\r | |
60 | \r | |
61 | When the function fails, output parameters are indeterminate.\r | |
62 | \r | |
63 | @param[out] PlatformConfig The platform configuration to receive the\r | |
64 | loaded data.\r | |
65 | \r | |
66 | @param[out] OptionalElements This bitmap describes the presence of optional\r | |
67 | configuration elements that have been loaded.\r | |
68 | PLATFORM_CONFIG_F_DOWNGRADE means that some\r | |
69 | unknown elements, present in the wire format,\r | |
70 | have been ignored.\r | |
71 | \r | |
72 | @retval EFI_SUCCESS Loading & deserialization successful.\r | |
73 | @return Error codes returned by GetVariable2().\r | |
74 | **/\r | |
75 | EFI_STATUS\r | |
76 | EFIAPI\r | |
77 | PlatformConfigLoad (\r | |
ac0a286f MK |
78 | OUT PLATFORM_CONFIG *PlatformConfig,\r |
79 | OUT UINT64 *OptionalElements\r | |
5267c89b LE |
80 | )\r |
81 | {\r | |
ac0a286f MK |
82 | VOID *Data;\r |
83 | UINTN DataSize;\r | |
84 | EFI_STATUS Status;\r | |
5267c89b LE |
85 | \r |
86 | //\r | |
87 | // Any translation done in PlatformConfigSave() would have to be mirrored\r | |
88 | // here. For now, just load the binary dump.\r | |
89 | //\r | |
90 | // Versioning of the binary wire format is implemented based on size\r | |
91 | // (only incremental changes, ie. new fields), and on GUID.\r | |
92 | // (Incompatible changes require a GUID change.)\r | |
93 | //\r | |
ac0a286f MK |
94 | Status = GetVariable2 (\r |
95 | mVariableName,\r | |
96 | &gOvmfPlatformConfigGuid,\r | |
97 | &Data,\r | |
98 | &DataSize\r | |
99 | );\r | |
5267c89b LE |
100 | if (EFI_ERROR (Status)) {\r |
101 | return Status;\r | |
102 | }\r | |
103 | \r | |
104 | *OptionalElements = 0;\r | |
105 | if (DataSize > sizeof *PlatformConfig) {\r | |
106 | //\r | |
107 | // Handle firmware downgrade -- keep only leading part.\r | |
108 | //\r | |
109 | CopyMem (PlatformConfig, Data, sizeof *PlatformConfig);\r | |
110 | *OptionalElements |= PLATFORM_CONFIG_F_DOWNGRADE;\r | |
111 | } else {\r | |
112 | CopyMem (PlatformConfig, Data, DataSize);\r | |
113 | \r | |
114 | //\r | |
115 | // Handle firmware upgrade -- zero out missing fields.\r | |
116 | //\r | |
ac0a286f MK |
117 | ZeroMem (\r |
118 | (UINT8 *)PlatformConfig + DataSize,\r | |
119 | sizeof *PlatformConfig - DataSize\r | |
120 | );\r | |
5267c89b LE |
121 | }\r |
122 | \r | |
123 | //\r | |
124 | // Based on DataSize, report the optional features that we recognize.\r | |
125 | //\r | |
126 | if (DataSize >= (OFFSET_OF (PLATFORM_CONFIG, VerticalResolution) +\r | |
ac0a286f MK |
127 | sizeof PlatformConfig->VerticalResolution))\r |
128 | {\r | |
5267c89b LE |
129 | *OptionalElements |= PLATFORM_CONFIG_F_GRAPHICS_RESOLUTION;\r |
130 | }\r | |
131 | \r | |
132 | FreePool (Data);\r | |
133 | return EFI_SUCCESS;\r | |
134 | }\r |