diff options
| author |   Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
|---|---|---|
| committer | Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
| commit | af1a266670d040d2f4083ff309d732d648afba2a (patch) | |
| tree | 2fc46203448ddcc6f81546d379abfaeb323575e9 /roms/edk2/OvmfPkg/PlatformDxe/PlatformConfig.c | |
| parent | e02cda008591317b1625707ff8e115a4841aa889 (diff) | |
Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec
Diffstat (limited to 'roms/edk2/OvmfPkg/PlatformDxe/PlatformConfig.c')
| -rw-r--r-- | roms/edk2/OvmfPkg/PlatformDxe/PlatformConfig.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/roms/edk2/OvmfPkg/PlatformDxe/PlatformConfig.c b/roms/edk2/OvmfPkg/PlatformDxe/PlatformConfig.c new file mode 100644 index 000000000..f3f0b54d6 --- /dev/null +++ b/roms/edk2/OvmfPkg/PlatformDxe/PlatformConfig.c @@ -0,0 +1,125 @@ +/** @file
+
+ Utility functions for serializing (persistently storing) and deserializing
+ OVMF's platform configuration.
+
+ Copyright (C) 2014, Red Hat, Inc.
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/BaseMemoryLib.h>
+#include <Library/DebugLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/UefiLib.h>
+#include <Library/UefiRuntimeServicesTableLib.h>
+#include <Guid/OvmfPlatformConfig.h>
+
+#include "PlatformConfig.h"
+
+//
+// Name of the UEFI variable that we use for persistent storage.
+//
+STATIC CHAR16 mVariableName[] = L"PlatformConfig";
+
+
+/**
+ Serialize and persistently save platform configuration.
+
+ @param[in] PlatformConfig The platform configuration to serialize and save.
+
+ @return Status codes returned by gRT->SetVariable().
+**/
+EFI_STATUS
+EFIAPI
+PlatformConfigSave (
+ IN PLATFORM_CONFIG *PlatformConfig
+ )
+{
+ EFI_STATUS Status;
+
+ //
+ // We could implement any kind of translation here, as part of serialization.
+ // For example, we could expose the platform configuration in separate
+ // variables with human-readable contents, allowing other tools to access
+ // them more easily. For now, just save a binary dump.
+ //
+ Status = gRT->SetVariable (mVariableName, &gOvmfPlatformConfigGuid,
+ EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS |
+ EFI_VARIABLE_RUNTIME_ACCESS,
+ sizeof *PlatformConfig, PlatformConfig);
+ return Status;
+}
+
+
+/**
+ Load and deserialize platform configuration.
+
+ When the function fails, output parameters are indeterminate.
+
+ @param[out] PlatformConfig The platform configuration to receive the
+ loaded data.
+
+ @param[out] OptionalElements This bitmap describes the presence of optional
+ configuration elements that have been loaded.
+ PLATFORM_CONFIG_F_DOWNGRADE means that some
+ unknown elements, present in the wire format,
+ have been ignored.
+
+ @retval EFI_SUCCESS Loading & deserialization successful.
+ @return Error codes returned by GetVariable2().
+**/
+EFI_STATUS
+EFIAPI
+PlatformConfigLoad (
+ OUT PLATFORM_CONFIG *PlatformConfig,
+ OUT UINT64 *OptionalElements
+ )
+{
+ VOID *Data;
+ UINTN DataSize;
+ EFI_STATUS Status;
+
+ //
+ // Any translation done in PlatformConfigSave() would have to be mirrored
+ // here. For now, just load the binary dump.
+ //
+ // Versioning of the binary wire format is implemented based on size
+ // (only incremental changes, ie. new fields), and on GUID.
+ // (Incompatible changes require a GUID change.)
+ //
+ Status = GetVariable2 (mVariableName, &gOvmfPlatformConfigGuid, &Data,
+ &DataSize);
+ if (EFI_ERROR (Status)) {
+ return Status;
+ }
+
+ *OptionalElements = 0;
+ if (DataSize > sizeof *PlatformConfig) {
+ //
+ // Handle firmware downgrade -- keep only leading part.
+ //
+ CopyMem (PlatformConfig, Data, sizeof *PlatformConfig);
+ *OptionalElements |= PLATFORM_CONFIG_F_DOWNGRADE;
+ } else {
+ CopyMem (PlatformConfig, Data, DataSize);
+
+ //
+ // Handle firmware upgrade -- zero out missing fields.
+ //
+ ZeroMem ((UINT8 *)PlatformConfig + DataSize,
+ sizeof *PlatformConfig - DataSize);
+ }
+
+ //
+ // Based on DataSize, report the optional features that we recognize.
+ //
+ if (DataSize >= (OFFSET_OF (PLATFORM_CONFIG, VerticalResolution) +
+ sizeof PlatformConfig->VerticalResolution)) {
+ *OptionalElements |= PLATFORM_CONFIG_F_GRAPHICS_RESOLUTION;
+ }
+
+ FreePool (Data);
+ return EFI_SUCCESS;
+}
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