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diff --git a/Lesson_16/README.md b/Lesson_16/README.md new file mode 100644 index 0000000..c67b529 --- /dev/null +++ b/Lesson_16/README.md @@ -0,0 +1,257 @@ +In previous lesson we've developed an app that showed us current boot options: +``` +FS0:\> ShowBootVariables.efi +Boot0000 +UiApp +Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331) + +Boot0001 +UEFI QEMU DVD-ROM QM00003 +PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0) + +Boot0002 +UEFI QEMU HARDDISK QM00001 +PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0) + +Boot0003* +EFI Internal Shell +Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(7C04A583-9E3E-4F1C-AD65-E05268D0B4D1) + +Boot0004 +UEFI PXEv4 (MAC:525400123456) +PciRoot(0x0)/Pci(0x3,0x0)/MAC(525400123456,0x1)/IPv4(0.0.0.0) +``` + +If you want to know information about the printed GUIDs here it is: +- `FILE_GUID = 7C04A583-9E3E-4f1c-AD65-E05268D0B4D1 # gUefiShellFileGuid` +https://github.com/tianocore/edk2/blob/master/ShellPkg/Application/Shell/Shell.inf +- `FILE_GUID = 462CAA21-7614-4503-836E-8AB6F4662331` - UiApp module is driver for BDS phase +https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Application/UiApp/UiApp.inf + +As for the `7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1` it is a GUID for the firmware volume in our OVMF image. +https://github.com/tianocore/edk2/blob/master/OvmfPkg/OvmfPkgX64.fdf + +This *.fdf file lists what drivers/apps are placed in every volume in the image (this includes volumes for SEC, PEI or DXE stages): +``` +... + +[FV.SECFV] +FvNameGuid = 763BED0D-DE9F-48F5-81F1-3E90E1B1A015 +BlockSize = 0x1000 +FvAlignment = 16 +... +INF <...> +... + +[FV.PEIFV] +FvNameGuid = 6938079B-B503-4E3D-9D24-B28337A25806 +BlockSize = 0x10000 +FvAlignment = 16 +... +INF <...> +... + +[FV.DXEFV] +FvForceRebase = FALSE +FvNameGuid = 7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1 ### <---- this is a GUID from our output +BlockSize = 0x10000 +FvAlignment = 16 +... +INF ShellPkg/Application/Shell/Shell.inf <--- this apps are placed in the FV.DXEFV firmware volume +... +INF MdeModulePkg/Application/UiApp/UiApp.inf +``` + +For the complete edk2 FDF file specification look at the https://edk2-docs.gitbook.io/edk-ii-fdf-specification/ + +If you look at the https://github.com/tianocore/edk2/blob/master/ShellPkg/Application/Shell/Shell.inf you'll see that EFI Shell is a simple `UEFI_APPLICATION`. We've developed a lot of those in these lessons, so let's try to add one of our apps to boot options. + +We will try to add our `HelloWorld` application to the boot options. We will look at how Shell app is included and try to do the same. + +First we need to add our app to OVMF image. So let's add `UefiLessonsPkg/HelloWorld/HelloWorld.inf` to the `[FV.DXEFV]` section next to `INF ShellPkg/Application/Shell/Shell.inf` in a `OvmfPkg/OvmfPkgX64.fdf b/OvmfPkg/OvmfPkgX64.fdf` we've already discussed. + +``` +[FV.DXEFV] +FvForceRebase = FALSE +FvNameGuid = 7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1 +BlockSize = 0x10000 +FvAlignment = 16 +... + + INF ShellPkg/Application/Shell/Shell.inf ++ INF UefiLessonsPkg/HelloWorld/HelloWorld.inf +... +``` + +If we try to build OVMF now we would get: +``` +$ build --platform=OvmfPkg/OvmfPkgX64.dsc --arch=X64 --buildtarget=RELEASE --tagname=GCC5 +... +build.py... + : error F001: Module /home/kostr/tiano/edk2/UefiLessonsPkg/HelloWorld/HelloWorld.inf NOT found in DSC file; Is it really a binary module? +... +``` + +Ok, so we need to add information to the `OvmfPkg/OvmfPkgX64.dsc` file. If you look at this file, you'll see that `ShellPkg/Application/Shell/Shell.inf` is listed under `[Components]` section. We've already used it in our first lesson when we've tried to compile our app without package. Add `UefiLessonsPkg/HelloWorld/HelloWorld.inf` next to the Shell INF file. +``` +[Components] + ... + ShellPkg/Application/Shell/Shell.inf { + ... + } ++ UefiLessonsPkg/HelloWorld/HelloWorld.inf + ... +``` +Shell.inf file has some information inside the brackets `{...}`. Don't mind it, we don't need such info for our simple `HelloWorld.inf`. + + +Now we can compile OVMF without errors: +``` +$ build --platform=OvmfPkg/OvmfPkgX64.dsc --arch=X64 --buildtarget=RELEASE --tagname=GCC5 +``` +Our `HelloWorld` app would be compiled and embedded in the OVMF image but unfortunately in wouldn't be listed in a boot options. + +When we used our `ShowBootVariables.efi` app we saw that UEFI shell boot option had a description `EFI Internal Shell`. Let's try search for that in a edk2 codebase: +``` +$ grep "EFI Internal Shell" -r ./ --exclude=Build +./ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c: &gUefiShellFileGuid, L"EFI Internal Shell", LOAD_OPTION_ACTIVE +./OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c: &gUefiShellFileGuid, L"EFI Internal Shell", LOAD_OPTION_ACTIVE +./OvmfPkg/Library/PlatformBootManagerLibBhyve/BdsPlatform.c: &gUefiShellFileGuid, L"EFI Internal Shell", LOAD_OPTION_ACTIVE +./OvmfPkg/Library/PlatformBootManagerLibGrub/BdsPlatform.c: &gUefiShellFileGuid, L"EFI Internal Shell", LOAD_OPTION_ACTIVE +``` + +For our case we're interested in a `./OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c` file: +``` +VOID +EFIAPI +PlatformBootManagerAfterConsole ( + VOID + ) +{ + ... + // + // Register UEFI Shell + // + PlatformRegisterFvBootOption ( + &gUefiShellFileGuid, L"EFI Internal Shell", LOAD_OPTION_ACTIVE + ); + + ... +} +``` +If you grep for a `gUefiShellFileGuid`: +``` +./OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c: &gUefiShellFileGuid, L"EFI Internal Shell", LOAD_OPTION_ACTIVE +./OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf: gUefiShellFileGuid +./ShellPkg/Application/Shell/Shell.inf: FILE_GUID = 7C04A583-9E3E-4f1c-AD65-E05268D0B4D1 # gUefiShellFileGuid +./ShellPkg/ShellPkg.dec: gUefiShellFileGuid = {0x7c04a583, 0x9e3e, 0x4f1c, {0xad, 0x65, 0xe0, 0x52, 0x68, 0xd0, 0xb4, 0xd1}} +``` + +Ok it looks like we need to create a `UefiLessonsPkg/UefiLessonsPkg.dec` file with something like `gHelloWorldFileGuid` with a value equal to the one that is listed in a `UefiLessonsPkg/HelloWorld/HelloWorld.inf` file. + +Let's do it: +``` +[Defines] + DEC_SPECIFICATION = 0x00010005 + PACKAGE_NAME = UefiLessonsPkg + PACKAGE_GUID = 7e7edbba-ca2c-4177-a3f0-d3371358773a + PACKAGE_VERSION = 1.01 + +[Guids] + # FILE_GUID as defined in UefiLessonsPkg/HelloWorld/HelloWorld.inf + gHelloWorldFileGuid = {0x2e55fa38, 0xf148, 0x42d3, {0xaf, 0x90, 0x1b, 0xe2, 0x47, 0x32, 0x3e, 0x30}} + +``` +EDK2 Package Declaration (DEC) File Format Specification can be found at link https://edk2-docs.gitbook.io/edk-ii-dec-specification/ + +Let's add our GUID to the `OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf` file +``` +[Guids] + ... + gUefiShellFileGuid ++ gHelloWorldFileGuid +``` +So we could use it in a `OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c` file: +``` +VOID +EFIAPI +PlatformBootManagerAfterConsole ( + VOID + ) +{ + ... + // + // Register UEFI Shell + // + PlatformRegisterFvBootOption ( + &gUefiShellFileGuid, L"EFI Internal Shell", LOAD_OPTION_ACTIVE + ); + + // + // Register HelloWorld app + // + PlatformRegisterFvBootOption ( + &gHelloWorldFileGuid, L"Hello World", LOAD_OPTION_ACTIVE + ); + ... +} +``` + +If we try to build OVMF now we would get an error: +``` +$ build --platform=OvmfPkg/OvmfPkgX64.dsc --arch=X64 --buildtarget=RELEASE --tagname=GCC5 +... + +build.py... +/home/kostr/tiano/edk2/OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf(87): error 4000: Value of Guid [gHelloWorldFileGuid] is not found under [Guids] section in + /home/kostr/tiano/edk2/MdePkg/MdePkg.dec + /home/kostr/tiano/edk2/MdeModulePkg/MdeModulePkg.dec + /home/kostr/tiano/edk2/SourceLevelDebugPkg/SourceLevelDebugPkg.dec + /home/kostr/tiano/edk2/OvmfPkg/OvmfPkg.dec + /home/kostr/tiano/edk2/SecurityPkg/SecurityPkg.dec + /home/kostr/tiano/edk2/ShellPkg/ShellPkg.dec +... +``` +To correct in we need our newly created `UefiLessonsPkg/UefiLessonsPkg.dec` to the `OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf`: +``` +[Packages] + ... + ShellPkg/ShellPkg.dec + UefiLessonsPkg/UefiLessonsPkg.dec +``` + +Finally we can successfully build OVMF. Let's run it and test our newly created boot option. + +Execute QEMU launch as usual. Now if you'll execute our `ShowBootVariables.efi` app you would get: +``` +FS0:\> ShowBootVariables.efi +Boot0000 +UiApp +Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331) + +Boot0001 +UEFI QEMU DVD-ROM QM00003 +PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0) + +Boot0002 +UEFI QEMU HARDDISK QM00001 +PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0) + +Boot0003* +EFI Internal Shell +Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(7C04A583-9E3E-4F1C-AD65-E05268D0B4D1) + +Boot0004 +Hello World +Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(2E55FA38-F148-42D3-AF90-1BE247323E30) + +Boot0005 +UEFI PXEv4 (MAC:525400123456) +PciRoot(0x0)/Pci(0x3,0x0)/MAC(525400123456,0x1)/IPv4(0.0.0.0) +``` + +Hooraay! Our boot option is present in the system. + +Just in case I've placed `Ovmf.diff` in this lesson folder that shows all the necessary changes. + + |