PCI Option ROM in BIOS | 易学教程

在BIOS里面包一个OpRom。
在启动过程中找到这个OpRom。
在内存里面查看这个OpRom的内容。

如何在BIOS里面包一个OpRom？如下，在OvmfPkgX64.fdf里面[FV.DXEFV]段加入下面的代码即可。

FILE FREEFORM = 1845d593-26a0-4805-a014-2e294fef14ee {     SECTION RAW = OvmfPkg/LegacyRom/rtegrom.lom     SECTION UI = "RealtekPXE"   }

如何找到这个OpRom？如下，遍历firmware volumes根据GUID找到这个OpRom的位置。

STATIC EFI_STATUS EFIAPI CHHGetOpRom (   OUT VOID  **RomImage,   OUT UINTN *RomSize   ) {   EFI_STATUS                    Status;   UINTN                         HandleCount;   EFI_HANDLE                    *HandleBuffer;   UINTN                         Index;   EFI_FIRMWARE_VOLUME2_PROTOCOL *FirmwareVolume;   UINT32                        AuthenticationStatus;   VOID                          *LocalRomImage;   UINTN                         LocalRomSize;    EFI_GUID gRealtekPXEOpRomGUID  = { 0x1845d593, 0x26a0, 0x4805, { 0xA0, 0x14, 0x2E, 0x29, 0x4F, 0xEF, 0x14, 0xEE } };  //GUID in OvmfPkgX64.fdf 1845d593-26a0-4805-a014-2e294fef14ee   // Get the list of available firmware volumes   //   Status = gBS->LocateHandleBuffer (                   ByProtocol,                   &gEfiFirmwareVolume2ProtocolGuid,                   NULL,                   &HandleCount,                   &HandleBuffer                   );   if (EFI_ERROR (Status) || HandleCount == 0) {     return EFI_NOT_FOUND;   }     //     // Loop through the Firmware Volumes looking for the Easton 815 Video ROM image     //     for (Index = 0; Index < HandleCount; Index++) {       //       // Get the Firmware Volume Protocol       //       Status = gBS->HandleProtocol (                       HandleBuffer[Index],                       &gEfiFirmwareVolume2ProtocolGuid,                       (VOID **) &FirmwareVolume                       );       if (EFI_ERROR (Status)) {         continue;       }       //       // Get the 16-bit BIOS code from the same Firmware Volume as this driver       //       LocalRomImage = NULL;       LocalRomSize  = 0;       Status = FirmwareVolume->ReadSection (                                  FirmwareVolume,                                  &gRealtekPXEOpRomGUID,                                  EFI_SECTION_RAW,                                  0,                                  &LocalRomImage,                                  &LocalRomSize,                                  &AuthenticationStatus                                  );       if (EFI_ERROR (Status)) {         continue;       }        DEBUG ((EFI_D_INFO, "Charles RomImage = 0x%X ;RomSize = 0x%X ;\n",LocalRomImage,LocalRomSize));       *RomImage = LocalRomImage;       *RomSize  = LocalRomSize;        FreePool (HandleBuffer);        return EFI_SUCCESS;     }    FreePool (HandleBuffer);    return EFI_NOT_FOUND; }

上面代码丢出来的Debug信息如下，

Charles RomImage = 0x7548018 ;RomSize = 0x11800 ;

如何在内存里面查看这个OpRom的内容？根据上面丢出来的OpRom的地址，在内存对应位置查看，可以看到OpRom signature "55AA"：

如何执行这个OpRom？

文章来源: PCI Option ROM in BIOS

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bios

pci