OvmfPkg/QemuFwCfgLib: Add SEV support
[mirror_edk2.git] / OvmfPkg / Library / QemuFwCfgLib / QemuFwCfgLib.c
CommitLineData
f1ec65ba 1/** @file\r
2\r
29874a8c 3 Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>\r
0dc231c9 4 Copyright (C) 2013, Red Hat, Inc.\r
2b631390 5 Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>\r
f1ec65ba 6\r
7 This program and the accompanying materials\r
8 are licensed and made available under the terms and conditions of the BSD License\r
9 which accompanies this distribution. The full text of the license may be found at\r
10 http://opensource.org/licenses/bsd-license.php\r
11\r
12 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
13 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
14\r
15**/\r
16\r
17#include "Uefi.h"\r
18#include <Library/BaseLib.h>\r
19#include <Library/BaseMemoryLib.h>\r
20#include <Library/DebugLib.h>\r
21#include <Library/IoLib.h>\r
22#include <Library/QemuFwCfgLib.h>\r
23#include <Library/MemoryAllocationLib.h>\r
24#include <Library/UefiBootServicesTableLib.h>\r
25\r
5297c0bf
LE
26#include "QemuFwCfgLibInternal.h"\r
27\r
f1ec65ba 28\r
f1ec65ba 29/**\r
30 Selects a firmware configuration item for reading.\r
31 \r
32 Following this call, any data read from this item will start from\r
33 the beginning of the configuration item's data.\r
34\r
35 @param[in] QemuFwCfgItem - Firmware Configuration item to read\r
36\r
37**/\r
38VOID\r
39EFIAPI\r
40QemuFwCfgSelectItem (\r
41 IN FIRMWARE_CONFIG_ITEM QemuFwCfgItem\r
42 )\r
43{\r
44 DEBUG ((EFI_D_INFO, "Select Item: 0x%x\n", (UINT16)(UINTN) QemuFwCfgItem));\r
21ca2f28 45 IoWrite16 (FW_CFG_IO_SELECTOR, (UINT16)(UINTN) QemuFwCfgItem);\r
f1ec65ba 46}\r
47\r
48\r
2c8dcbc6 49/**\r
d055601e
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50 Transfer an array of bytes, or skip a number of bytes, using the DMA\r
51 interface.\r
2c8dcbc6 52\r
d055601e
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53 @param[in] Size Size in bytes to transfer or skip.\r
54\r
55 @param[in,out] Buffer Buffer to read data into or write data from. Ignored,\r
56 and may be NULL, if Size is zero, or Control is\r
57 FW_CFG_DMA_CTL_SKIP.\r
58\r
59 @param[in] Control One of the following:\r
60 FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.\r
61 FW_CFG_DMA_CTL_READ - read from fw_cfg into Buffer.\r
62 FW_CFG_DMA_CTL_SKIP - skip bytes in fw_cfg.\r
2c8dcbc6
LE
63**/\r
64VOID\r
65InternalQemuFwCfgDmaBytes (\r
66 IN UINT32 Size,\r
67 IN OUT VOID *Buffer OPTIONAL,\r
d055601e 68 IN UINT32 Control\r
2c8dcbc6
LE
69 )\r
70{\r
7cfe445d
BS
71 volatile FW_CFG_DMA_ACCESS LocalAccess;\r
72 volatile FW_CFG_DMA_ACCESS *Access;\r
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LE
73 UINT32 AccessHigh, AccessLow;\r
74 UINT32 Status;\r
66c548be
BS
75 UINT32 NumPages;\r
76 VOID *DmaBuffer, *BounceBuffer;\r
2c8dcbc6 77\r
d055601e
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78 ASSERT (Control == FW_CFG_DMA_CTL_WRITE || Control == FW_CFG_DMA_CTL_READ ||\r
79 Control == FW_CFG_DMA_CTL_SKIP);\r
80\r
2c8dcbc6
LE
81 if (Size == 0) {\r
82 return;\r
83 }\r
84\r
66c548be
BS
85 //\r
86 // When SEV is enabled then allocate DMA bounce buffer\r
87 //\r
88 if (InternalQemuFwCfgSevIsEnabled ()) {\r
89 UINTN TotalSize;\r
90\r
91 TotalSize = sizeof (*Access);\r
92 //\r
93 // Skip operation does not need buffer\r
94 //\r
95 if (Control != FW_CFG_DMA_CTL_SKIP) {\r
96 TotalSize += Size;\r
97 }\r
98\r
99 //\r
100 // Allocate SEV DMA buffer\r
101 //\r
102 NumPages = (UINT32)EFI_SIZE_TO_PAGES (TotalSize);\r
103 InternalQemuFwCfgSevDmaAllocateBuffer (&BounceBuffer, NumPages);\r
104\r
105 Access = BounceBuffer;\r
106 DmaBuffer = (UINT8*)BounceBuffer + sizeof (*Access);\r
107\r
108 //\r
109 // Decrypt data from encrypted guest buffer into DMA buffer\r
110 //\r
111 if (Control == FW_CFG_DMA_CTL_WRITE) {\r
112 CopyMem (DmaBuffer, Buffer, Size);\r
113 }\r
114 } else {\r
115 Access = &LocalAccess;\r
116 DmaBuffer = Buffer;\r
117 BounceBuffer = NULL;\r
118 }\r
7cfe445d
BS
119\r
120 Access->Control = SwapBytes32 (Control);\r
121 Access->Length = SwapBytes32 (Size);\r
66c548be 122 Access->Address = SwapBytes64 ((UINTN)DmaBuffer);\r
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LE
123\r
124 //\r
125 // Delimit the transfer from (a) modifications to Access, (b) in case of a\r
126 // write, from writes to Buffer by the caller.\r
127 //\r
128 MemoryFence ();\r
129\r
130 //\r
131 // Start the transfer.\r
132 //\r
7cfe445d
BS
133 AccessHigh = (UINT32)RShiftU64 ((UINTN)Access, 32);\r
134 AccessLow = (UINT32)(UINTN)Access;\r
ed1a2d42
LE
135 IoWrite32 (FW_CFG_IO_DMA_ADDRESS, SwapBytes32 (AccessHigh));\r
136 IoWrite32 (FW_CFG_IO_DMA_ADDRESS + 4, SwapBytes32 (AccessLow));\r
2c8dcbc6
LE
137\r
138 //\r
139 // Don't look at Access.Control before starting the transfer.\r
140 //\r
141 MemoryFence ();\r
142\r
143 //\r
144 // Wait for the transfer to complete.\r
145 //\r
146 do {\r
7cfe445d 147 Status = SwapBytes32 (Access->Control);\r
2c8dcbc6
LE
148 ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);\r
149 } while (Status != 0);\r
150\r
151 //\r
152 // After a read, the caller will want to use Buffer.\r
153 //\r
154 MemoryFence ();\r
66c548be
BS
155\r
156 //\r
157 // If Bounce buffer was allocated then copy the data into guest buffer and\r
158 // free the bounce buffer\r
159 //\r
160 if (BounceBuffer != NULL) {\r
161 //\r
162 // Encrypt the data from DMA buffer into guest buffer\r
163 //\r
164 if (Control == FW_CFG_DMA_CTL_READ) {\r
165 CopyMem (Buffer, DmaBuffer, Size);\r
166 }\r
167\r
168 InternalQemuFwCfgSevDmaFreeBuffer (BounceBuffer, NumPages);\r
169 }\r
2c8dcbc6
LE
170}\r
171\r
172\r
f1ec65ba 173/**\r
174 Reads firmware configuration bytes into a buffer\r
175\r
176 @param[in] Size - Size in bytes to read\r
177 @param[in] Buffer - Buffer to store data into (OPTIONAL if Size is 0)\r
178\r
179**/\r
180VOID\r
181EFIAPI\r
182InternalQemuFwCfgReadBytes (\r
183 IN UINTN Size,\r
184 IN VOID *Buffer OPTIONAL\r
185 )\r
186{\r
2c8dcbc6 187 if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {\r
d055601e 188 InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_READ);\r
2c8dcbc6
LE
189 return;\r
190 }\r
509e6b5a 191 IoReadFifo8 (FW_CFG_IO_DATA, Size, Buffer);\r
f1ec65ba 192}\r
193\r
194\r
195/**\r
196 Reads firmware configuration bytes into a buffer\r
197\r
198 If called multiple times, then the data read will\r
199 continue at the offset of the firmware configuration\r
200 item where the previous read ended.\r
201\r
202 @param[in] Size - Size in bytes to read\r
203 @param[in] Buffer - Buffer to store data into\r
204\r
205**/\r
206VOID\r
207EFIAPI\r
208QemuFwCfgReadBytes (\r
209 IN UINTN Size,\r
210 IN VOID *Buffer\r
211 )\r
212{\r
0dc231c9 213 if (InternalQemuFwCfgIsAvailable ()) {\r
f1ec65ba 214 InternalQemuFwCfgReadBytes (Size, Buffer);\r
215 } else {\r
216 ZeroMem (Buffer, Size);\r
217 }\r
218}\r
219\r
29874a8c 220/**\r
221 Write firmware configuration bytes from a buffer\r
222\r
223 If called multiple times, then the data written will\r
224 continue at the offset of the firmware configuration\r
225 item where the previous write ended.\r
226\r
227 @param[in] Size - Size in bytes to write\r
228 @param[in] Buffer - Buffer to read data from\r
229\r
230**/\r
231VOID\r
232EFIAPI\r
233QemuFwCfgWriteBytes (\r
234 IN UINTN Size,\r
235 IN VOID *Buffer\r
236 )\r
237{\r
0dc231c9 238 if (InternalQemuFwCfgIsAvailable ()) {\r
2c8dcbc6 239 if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {\r
d055601e 240 InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_WRITE);\r
2c8dcbc6
LE
241 return;\r
242 }\r
509e6b5a 243 IoWriteFifo8 (FW_CFG_IO_DATA, Size, Buffer);\r
29874a8c 244 }\r
245}\r
246\r
f1ec65ba 247\r
fcca9f67
LE
248/**\r
249 Skip bytes in the firmware configuration item.\r
250\r
251 Increase the offset of the firmware configuration item without transferring\r
252 bytes between the item and a caller-provided buffer. Subsequent read, write\r
253 or skip operations will commence at the increased offset.\r
254\r
255 @param[in] Size Number of bytes to skip.\r
256**/\r
257VOID\r
258EFIAPI\r
259QemuFwCfgSkipBytes (\r
260 IN UINTN Size\r
261 )\r
262{\r
263 UINTN ChunkSize;\r
264 UINT8 SkipBuffer[256];\r
265\r
266 if (!InternalQemuFwCfgIsAvailable ()) {\r
267 return;\r
268 }\r
269\r
270 if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {\r
271 InternalQemuFwCfgDmaBytes ((UINT32)Size, NULL, FW_CFG_DMA_CTL_SKIP);\r
272 return;\r
273 }\r
274\r
275 //\r
276 // Emulate the skip by reading data in chunks, and throwing it away. The\r
277 // implementation below is suitable even for phases where RAM or dynamic\r
278 // allocation is not available or appropriate. It also doesn't affect the\r
279 // static data footprint for client modules. Large skips are not expected,\r
280 // therefore this fallback is not performance critical. The size of\r
281 // SkipBuffer is thought not to exert a large pressure on the stack in any\r
282 // phase.\r
283 //\r
284 while (Size > 0) {\r
285 ChunkSize = MIN (Size, sizeof SkipBuffer);\r
509e6b5a 286 IoReadFifo8 (FW_CFG_IO_DATA, ChunkSize, SkipBuffer);\r
fcca9f67
LE
287 Size -= ChunkSize;\r
288 }\r
289}\r
290\r
291\r
f1ec65ba 292/**\r
293 Reads a UINT8 firmware configuration value\r
294\r
295 @return Value of Firmware Configuration item read\r
296\r
297**/\r
298UINT8\r
299EFIAPI\r
300QemuFwCfgRead8 (\r
301 VOID\r
302 )\r
303{\r
304 UINT8 Result;\r
305\r
306 QemuFwCfgReadBytes (sizeof (Result), &Result);\r
307\r
308 return Result;\r
309}\r
310\r
311\r
312/**\r
313 Reads a UINT16 firmware configuration value\r
314\r
315 @return Value of Firmware Configuration item read\r
316\r
317**/\r
318UINT16\r
319EFIAPI\r
320QemuFwCfgRead16 (\r
321 VOID\r
322 )\r
323{\r
324 UINT16 Result;\r
325\r
326 QemuFwCfgReadBytes (sizeof (Result), &Result);\r
327\r
328 return Result;\r
329}\r
330\r
331\r
332/**\r
333 Reads a UINT32 firmware configuration value\r
334\r
335 @return Value of Firmware Configuration item read\r
336\r
337**/\r
338UINT32\r
339EFIAPI\r
340QemuFwCfgRead32 (\r
341 VOID\r
342 )\r
343{\r
344 UINT32 Result;\r
345\r
346 QemuFwCfgReadBytes (sizeof (Result), &Result);\r
347\r
348 return Result;\r
349}\r
350\r
351\r
352/**\r
353 Reads a UINT64 firmware configuration value\r
354\r
355 @return Value of Firmware Configuration item read\r
356\r
357**/\r
358UINT64\r
359EFIAPI\r
360QemuFwCfgRead64 (\r
361 VOID\r
362 )\r
363{\r
364 UINT64 Result;\r
365\r
366 QemuFwCfgReadBytes (sizeof (Result), &Result);\r
367\r
368 return Result;\r
369}\r
370\r
371\r
0ac9bc9b 372/**\r
373 Find the configuration item corresponding to the firmware configuration file.\r
374\r
375 @param[in] Name - Name of file to look up.\r
376 @param[out] Item - Configuration item corresponding to the file, to be passed\r
377 to QemuFwCfgSelectItem ().\r
378 @param[out] Size - Number of bytes in the file.\r
379\r
380 @return RETURN_SUCCESS If file is found.\r
381 RETURN_NOT_FOUND If file is not found.\r
382 RETURN_UNSUPPORTED If firmware configuration is unavailable.\r
383\r
384**/\r
385RETURN_STATUS\r
386EFIAPI\r
387QemuFwCfgFindFile (\r
388 IN CONST CHAR8 *Name,\r
389 OUT FIRMWARE_CONFIG_ITEM *Item,\r
390 OUT UINTN *Size\r
391 )\r
392{\r
393 UINT32 Count;\r
394 UINT32 Idx;\r
395\r
0dc231c9 396 if (!InternalQemuFwCfgIsAvailable ()) {\r
0ac9bc9b 397 return RETURN_UNSUPPORTED;\r
398 }\r
399\r
400 QemuFwCfgSelectItem (QemuFwCfgItemFileDir);\r
401 Count = SwapBytes32 (QemuFwCfgRead32 ());\r
402\r
403 for (Idx = 0; Idx < Count; ++Idx) {\r
404 UINT32 FileSize;\r
405 UINT16 FileSelect;\r
406 UINT16 FileReserved;\r
6a904296 407 CHAR8 FName[QEMU_FW_CFG_FNAME_SIZE];\r
0ac9bc9b 408\r
409 FileSize = QemuFwCfgRead32 ();\r
410 FileSelect = QemuFwCfgRead16 ();\r
411 FileReserved = QemuFwCfgRead16 ();\r
c6910aed 412 (VOID) FileReserved; /* Force a do-nothing reference. */\r
0ac9bc9b 413 InternalQemuFwCfgReadBytes (sizeof (FName), FName);\r
414\r
415 if (AsciiStrCmp (Name, FName) == 0) {\r
416 *Item = SwapBytes16 (FileSelect);\r
417 *Size = SwapBytes32 (FileSize);\r
418 return RETURN_SUCCESS;\r
419 }\r
420 }\r
421\r
422 return RETURN_NOT_FOUND;\r
423}\r