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-rw-r--r--OvmfPkg/Include/Library/QemuFwCfgLib.h21
-rw-r--r--OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c53
2 files changed, 74 insertions, 0 deletions
diff --git a/OvmfPkg/Include/Library/QemuFwCfgLib.h b/OvmfPkg/Include/Library/QemuFwCfgLib.h
index 5a3db7e809..3776d79ea9 100644
--- a/OvmfPkg/Include/Library/QemuFwCfgLib.h
+++ b/OvmfPkg/Include/Library/QemuFwCfgLib.h
@@ -41,6 +41,7 @@ typedef enum {
QemuFwCfgItemKernelSetupAddress = 0x0016,
QemuFwCfgItemKernelSetupSize = 0x0017,
QemuFwCfgItemKernelSetupData = 0x0018,
+ QemuFwCfgItemFileDir = 0x0019,
QemuFwCfgItemX86AcpiTables = 0x8000,
QemuFwCfgItemX86SmbiosTables = 0x8001,
@@ -153,5 +154,25 @@ QemuFwCfgRead64 (
);
+/**
+ Find the configuration item corresponding to the firmware configuration file.
+
+ @param[in] Name - Name of file to look up.
+ @param[out] Item - Configuration item corresponding to the file, to be passed
+ to QemuFwCfgSelectItem ().
+ @param[out] Size - Number of bytes in the file.
+
+ @return RETURN_SUCCESS If file is found.
+ RETURN_NOT_FOUND If file is not found.
+ RETURN_UNSUPPORTED If firmware configuration is unavailable.
+
+**/
+RETURN_STATUS
+EFIAPI
+QemuFwCfgFindFile (
+ IN CONST CHAR8 *Name,
+ OUT FIRMWARE_CONFIG_ITEM *Item,
+ OUT UINTN *Size
+ );
#endif
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
index b94dc67392..8caab42e8b 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
@@ -244,3 +244,56 @@ QemuFwCfgInitialize (
DEBUG ((EFI_D_INFO, "QemuFwCfg interface is supported.\n"));
return RETURN_SUCCESS;
}
+
+
+/**
+ Find the configuration item corresponding to the firmware configuration file.
+
+ @param[in] Name - Name of file to look up.
+ @param[out] Item - Configuration item corresponding to the file, to be passed
+ to QemuFwCfgSelectItem ().
+ @param[out] Size - Number of bytes in the file.
+
+ @return RETURN_SUCCESS If file is found.
+ RETURN_NOT_FOUND If file is not found.
+ RETURN_UNSUPPORTED If firmware configuration is unavailable.
+
+**/
+RETURN_STATUS
+EFIAPI
+QemuFwCfgFindFile (
+ IN CONST CHAR8 *Name,
+ OUT FIRMWARE_CONFIG_ITEM *Item,
+ OUT UINTN *Size
+ )
+{
+ UINT32 Count;
+ UINT32 Idx;
+
+ if (!mQemuFwCfgSupported) {
+ return RETURN_UNSUPPORTED;
+ }
+
+ QemuFwCfgSelectItem (QemuFwCfgItemFileDir);
+ Count = SwapBytes32 (QemuFwCfgRead32 ());
+
+ for (Idx = 0; Idx < Count; ++Idx) {
+ UINT32 FileSize;
+ UINT16 FileSelect;
+ UINT16 FileReserved;
+ CHAR8 FName[56];
+
+ FileSize = QemuFwCfgRead32 ();
+ FileSelect = QemuFwCfgRead16 ();
+ FileReserved = QemuFwCfgRead16 ();
+ InternalQemuFwCfgReadBytes (sizeof (FName), FName);
+
+ if (AsciiStrCmp (Name, FName) == 0) {
+ *Item = SwapBytes16 (FileSelect);
+ *Size = SwapBytes32 (FileSize);
+ return RETURN_SUCCESS;
+ }
+ }
+
+ return RETURN_NOT_FOUND;
+}