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2ce7e221 LE |
1 | /** @file\r |
2 | \r | |
3 | Stateful and implicitly initialized fw_cfg library implementation.\r | |
4 | \r | |
5 | Copyright (C) 2013, Red Hat, Inc.\r | |
6 | Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>\r | |
5feae253 | 7 | Copyright (c) 2017, Advanced Micro Devices. All rights reserved.<BR>\r |
2ce7e221 | 8 | \r |
b26f0cf9 | 9 | SPDX-License-Identifier: BSD-2-Clause-Patent\r |
2ce7e221 LE |
10 | **/\r |
11 | \r | |
5feae253 | 12 | #include <Library/BaseLib.h>\r |
f6c909ae | 13 | #include <Library/IoLib.h>\r |
2ce7e221 LE |
14 | #include <Library/DebugLib.h>\r |
15 | #include <Library/QemuFwCfgLib.h>\r | |
5feae253 | 16 | #include <Library/MemEncryptSevLib.h>\r |
2ce7e221 | 17 | \r |
5297c0bf LE |
18 | #include "QemuFwCfgLibInternal.h"\r |
19 | \r | |
2ce7e221 | 20 | STATIC BOOLEAN mQemuFwCfgSupported = FALSE;\r |
2c8dcbc6 | 21 | STATIC BOOLEAN mQemuFwCfgDmaSupported;\r |
2ce7e221 LE |
22 | \r |
23 | \r | |
24 | /**\r | |
25 | Returns a boolean indicating if the firmware configuration interface\r | |
26 | is available or not.\r | |
27 | \r | |
28 | This function may change fw_cfg state.\r | |
29 | \r | |
30 | @retval TRUE The interface is available\r | |
31 | @retval FALSE The interface is not available\r | |
32 | \r | |
33 | **/\r | |
34 | BOOLEAN\r | |
35 | EFIAPI\r | |
36 | QemuFwCfgIsAvailable (\r | |
37 | VOID\r | |
38 | )\r | |
39 | {\r | |
40 | return InternalQemuFwCfgIsAvailable ();\r | |
41 | }\r | |
42 | \r | |
43 | \r | |
44 | RETURN_STATUS\r | |
45 | EFIAPI\r | |
46 | QemuFwCfgInitialize (\r | |
47 | VOID\r | |
48 | )\r | |
49 | {\r | |
50 | UINT32 Signature;\r | |
51 | UINT32 Revision;\r | |
52 | \r | |
53 | //\r | |
54 | // Enable the access routines while probing to see if it is supported.\r | |
2c8dcbc6 | 55 | // For probing we always use the IO Port (IoReadFifo8()) access method.\r |
2ce7e221 LE |
56 | //\r |
57 | mQemuFwCfgSupported = TRUE;\r | |
2c8dcbc6 | 58 | mQemuFwCfgDmaSupported = FALSE;\r |
2ce7e221 LE |
59 | \r |
60 | QemuFwCfgSelectItem (QemuFwCfgItemSignature);\r | |
61 | Signature = QemuFwCfgRead32 ();\r | |
70d5086c | 62 | DEBUG ((DEBUG_INFO, "FW CFG Signature: 0x%x\n", Signature));\r |
2ce7e221 LE |
63 | QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);\r |
64 | Revision = QemuFwCfgRead32 ();\r | |
70d5086c | 65 | DEBUG ((DEBUG_INFO, "FW CFG Revision: 0x%x\n", Revision));\r |
2ce7e221 LE |
66 | if ((Signature != SIGNATURE_32 ('Q', 'E', 'M', 'U')) ||\r |
67 | (Revision < 1)\r | |
68 | ) {\r | |
70d5086c | 69 | DEBUG ((DEBUG_INFO, "QemuFwCfg interface not supported.\n"));\r |
2ce7e221 LE |
70 | mQemuFwCfgSupported = FALSE;\r |
71 | return RETURN_SUCCESS;\r | |
72 | }\r | |
73 | \r | |
2c8dcbc6 LE |
74 | if ((Revision & FW_CFG_F_DMA) == 0) {\r |
75 | DEBUG ((DEBUG_INFO, "QemuFwCfg interface (IO Port) is supported.\n"));\r | |
76 | } else {\r | |
5feae253 BS |
77 | //\r |
78 | // If SEV is enabled then we do not support DMA operations in PEI phase.\r | |
79 | // This is mainly because DMA in SEV guest requires using bounce buffer\r | |
80 | // (which need to allocate dynamic memory and allocating a PAGE size'd\r | |
81 | // buffer can be challenge in PEI phase)\r | |
82 | //\r | |
f6c909ae | 83 | if (MemEncryptSevIsEnabled ()) {\r |
5feae253 BS |
84 | DEBUG ((DEBUG_INFO, "SEV: QemuFwCfg fallback to IO Port interface.\n"));\r |
85 | } else {\r | |
86 | mQemuFwCfgDmaSupported = TRUE;\r | |
87 | DEBUG ((DEBUG_INFO, "QemuFwCfg interface (DMA) is supported.\n"));\r | |
88 | }\r | |
2c8dcbc6 | 89 | }\r |
2ce7e221 LE |
90 | return RETURN_SUCCESS;\r |
91 | }\r | |
92 | \r | |
93 | \r | |
94 | /**\r | |
95 | Returns a boolean indicating if the firmware configuration interface is\r | |
96 | available for library-internal purposes.\r | |
97 | \r | |
98 | This function never changes fw_cfg state.\r | |
99 | \r | |
100 | @retval TRUE The interface is available internally.\r | |
101 | @retval FALSE The interface is not available internally.\r | |
102 | **/\r | |
103 | BOOLEAN\r | |
2ce7e221 LE |
104 | InternalQemuFwCfgIsAvailable (\r |
105 | VOID\r | |
106 | )\r | |
107 | {\r | |
108 | return mQemuFwCfgSupported;\r | |
109 | }\r | |
2c8dcbc6 LE |
110 | \r |
111 | /**\r | |
112 | Returns a boolean indicating whether QEMU provides the DMA-like access method\r | |
113 | for fw_cfg.\r | |
114 | \r | |
115 | @retval TRUE The DMA-like access method is available.\r | |
116 | @retval FALSE The DMA-like access method is unavailable.\r | |
117 | **/\r | |
118 | BOOLEAN\r | |
119 | InternalQemuFwCfgDmaIsAvailable (\r | |
120 | VOID\r | |
121 | )\r | |
122 | {\r | |
123 | return mQemuFwCfgDmaSupported;\r | |
124 | }\r | |
5feae253 BS |
125 | \r |
126 | /**\r | |
f6c909ae BS |
127 | Transfer an array of bytes, or skip a number of bytes, using the DMA\r |
128 | interface.\r | |
5feae253 | 129 | \r |
f6c909ae | 130 | @param[in] Size Size in bytes to transfer or skip.\r |
5feae253 | 131 | \r |
f6c909ae BS |
132 | @param[in,out] Buffer Buffer to read data into or write data from. Ignored,\r |
133 | and may be NULL, if Size is zero, or Control is\r | |
134 | FW_CFG_DMA_CTL_SKIP.\r | |
135 | \r | |
136 | @param[in] Control One of the following:\r | |
137 | FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.\r | |
138 | FW_CFG_DMA_CTL_READ - read from fw_cfg into Buffer.\r | |
139 | FW_CFG_DMA_CTL_SKIP - skip bytes in fw_cfg.\r | |
5feae253 | 140 | **/\r |
f6c909ae BS |
141 | VOID\r |
142 | InternalQemuFwCfgDmaBytes (\r | |
143 | IN UINT32 Size,\r | |
144 | IN OUT VOID *Buffer OPTIONAL,\r | |
145 | IN UINT32 Control\r | |
5feae253 BS |
146 | )\r |
147 | {\r | |
f6c909ae BS |
148 | volatile FW_CFG_DMA_ACCESS Access;\r |
149 | UINT32 AccessHigh, AccessLow;\r | |
150 | UINT32 Status;\r | |
5feae253 | 151 | \r |
f6c909ae BS |
152 | ASSERT (Control == FW_CFG_DMA_CTL_WRITE || Control == FW_CFG_DMA_CTL_READ ||\r |
153 | Control == FW_CFG_DMA_CTL_SKIP);\r | |
5feae253 | 154 | \r |
f6c909ae BS |
155 | if (Size == 0) {\r |
156 | return;\r | |
157 | }\r | |
5feae253 | 158 | \r |
5feae253 | 159 | //\r |
f6c909ae BS |
160 | // SEV does not support DMA operations in PEI stage, we should\r |
161 | // not have reached here.\r | |
5feae253 | 162 | //\r |
f6c909ae | 163 | ASSERT (!MemEncryptSevIsEnabled ());\r |
5feae253 | 164 | \r |
f6c909ae BS |
165 | Access.Control = SwapBytes32 (Control);\r |
166 | Access.Length = SwapBytes32 (Size);\r | |
167 | Access.Address = SwapBytes64 ((UINTN)Buffer);\r | |
5feae253 | 168 | \r |
f6c909ae BS |
169 | //\r |
170 | // Delimit the transfer from (a) modifications to Access, (b) in case of a\r | |
171 | // write, from writes to Buffer by the caller.\r | |
172 | //\r | |
173 | MemoryFence ();\r | |
174 | \r | |
175 | //\r | |
176 | // Start the transfer.\r | |
177 | //\r | |
178 | AccessHigh = (UINT32)RShiftU64 ((UINTN)&Access, 32);\r | |
179 | AccessLow = (UINT32)(UINTN)&Access;\r | |
180 | IoWrite32 (FW_CFG_IO_DMA_ADDRESS, SwapBytes32 (AccessHigh));\r | |
181 | IoWrite32 (FW_CFG_IO_DMA_ADDRESS + 4, SwapBytes32 (AccessLow));\r | |
5feae253 | 182 | \r |
5feae253 | 183 | //\r |
f6c909ae | 184 | // Don't look at Access.Control before starting the transfer.\r |
5feae253 | 185 | //\r |
f6c909ae BS |
186 | MemoryFence ();\r |
187 | \r | |
188 | //\r | |
189 | // Wait for the transfer to complete.\r | |
190 | //\r | |
191 | do {\r | |
192 | Status = SwapBytes32 (Access.Control);\r | |
193 | ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);\r | |
194 | } while (Status != 0);\r | |
195 | \r | |
196 | //\r | |
197 | // After a read, the caller will want to use Buffer.\r | |
198 | //\r | |
199 | MemoryFence ();\r | |
5feae253 | 200 | }\r |
f6c909ae | 201 | \r |