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1 | /** @file\r |
2 | OVMF support for QEMU system firmware flash device: functions specific to the\r | |
3 | runtime DXE driver build.\r | |
4 | \r | |
5 | Copyright (C) 2015, Red Hat, Inc.\r | |
6 | Copyright (c) 2009 - 2013, Intel Corporation. All rights reserved.<BR>\r | |
7 | \r | |
b26f0cf9 | 8 | SPDX-License-Identifier: BSD-2-Clause-Patent\r |
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9 | \r |
10 | **/\r | |
11 | \r | |
12 | #include <Library/UefiRuntimeLib.h>\r | |
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13 | #include <Library/MemEncryptSevLib.h>\r |
14 | #include <Library/VmgExitLib.h>\r | |
15 | #include <Register/Amd/Msr.h>\r | |
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16 | \r |
17 | #include "QemuFlash.h"\r | |
18 | \r | |
19 | VOID\r | |
20 | QemuFlashConvertPointers (\r | |
21 | VOID\r | |
22 | )\r | |
23 | {\r | |
24 | EfiConvertPointer (0x0, (VOID **) &mFlashBase);\r | |
25 | }\r | |
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26 | \r |
27 | VOID\r | |
28 | QemuFlashBeforeProbe (\r | |
29 | IN EFI_PHYSICAL_ADDRESS BaseAddress,\r | |
30 | IN UINTN FdBlockSize,\r | |
31 | IN UINTN FdBlockCount\r | |
32 | )\r | |
33 | {\r | |
34 | //\r | |
35 | // Do nothing\r | |
36 | //\r | |
37 | }\r | |
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38 | \r |
39 | /**\r | |
40 | Write to QEMU Flash\r | |
41 | \r | |
42 | @param[in] Ptr Pointer to the location to write.\r | |
43 | @param[in] Value The value to write.\r | |
44 | \r | |
45 | **/\r | |
46 | VOID\r | |
47 | QemuFlashPtrWrite (\r | |
48 | IN volatile UINT8 *Ptr,\r | |
49 | IN UINT8 Value\r | |
50 | )\r | |
51 | {\r | |
52 | if (MemEncryptSevEsIsEnabled ()) {\r | |
53 | MSR_SEV_ES_GHCB_REGISTER Msr;\r | |
54 | GHCB *Ghcb;\r | |
55 | \r | |
56 | Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);\r | |
57 | Ghcb = Msr.Ghcb;\r | |
58 | \r | |
59 | //\r | |
60 | // Writing to flash is emulated by the hypervisor through the use of write\r | |
61 | // protection. This won't work for an SEV-ES guest because the write won't\r | |
62 | // be recognized as a true MMIO write, which would result in the required\r | |
63 | // #VC exception. Instead, use the the VMGEXIT MMIO write support directly\r | |
64 | // to perform the update.\r | |
65 | //\r | |
66 | VmgInit (Ghcb);\r | |
67 | Ghcb->SharedBuffer[0] = Value;\r | |
68 | Ghcb->SaveArea.SwScratch = (UINT64) (UINTN) Ghcb->SharedBuffer;\r | |
69 | VmgExit (Ghcb, SVM_EXIT_MMIO_WRITE, (UINT64) (UINTN) Ptr, 1);\r | |
70 | VmgDone (Ghcb);\r | |
71 | } else {\r | |
72 | *Ptr = Value;\r | |
73 | }\r | |
74 | }\r |