Hi Takahiro,
On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi takahiro.akashi@linaro.org wrote:
On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
Hi Heinrich, Ilias, Akashi-san,
Ilias and I are now discussing to create efi bootmenu, almost similar to UiApp in EDK2.
Why not discuss this topic openly in ML?
Yes, I included U-Boot ML.(Sorry, I should include from the the beginning.)
How is this feature related to Simon's bootmethod proposal?
If I correctly understand Simon's bootmethod proposal, the difference is that efi bootmenu only targets to implement the menu based UI to select/edit/add/delete "Boot####" and "BootOrder".
Here is some background.
U-Boot's command line should be completely disabled on secure devices. However since U-Boot doesn't (yet) support EFI runtime SetVariable for all supported devices, disabling the command line is hard, if even possible. If we provide a boot menu, with access to very limited functionality, e.g select a boot option and allow users to add/edit/delete existing options, we can enhance security and provide a usable alternative to the users.
In addition, if we can add options for managing EFI keys and enabling disabling secure boot, we can completely get rid of the u-boot cmd line, greatly enhancing platform security
Basically, it will be a good idea. Please keep in mind, however, that add/deleting boot options, [en|dis]abling secure boot or modifying secure variables should belong to some sort of privileged operations. I think that we need to have some mechanism to distinguish them from other menus. It might be system specific, though.
===
I am planning to hook the existing "bootefi bootmgr" boot process. In "bootefi bootmgr", the planned process will be as follows.
- check "BootNext"
What do you mean by "check"?
I meant the existing bootmgr implementation. If "BootNext" is specified, system boots with "BootNext".
- show efi bootmenu (*NEW*)
- if user quits efi bootmenu, then boot in accordance with "BootOrder"
It means efi bootmenu is native u-boot program.
I would like to hear your opinion how this efi bootmenu should be implemented. Is it better to implement as EFI application?
In my personal opinion, we should implement the feature as a separate EFI application. One of benefits of UEFI interfaces are the ability to expand functionality with driver modules and applications without modifying the core. (One example is iPXE boot that Heinrich often picks up in his comments.)
If it is an EFI application, it can be easily replaced with others per system and we may be able to use secure boot to authorise the app itself.
Thank you, I understand the benefit of implementing as EFI App.
But implementing it as an EFI app is not the goal, and I think you can start with what you want to do first.
Note that I tried to run edk2 UiApp on U-Boot, I found that the following protocol are required and assertion occurs in DEBUG build. gEfiHiiConfigRoutingProtocolGuid gEfiHiiFontProtocolGuid gEfiHiiImageProtocolGuid Probably these protocols can be implemented as dummy stub. If I run UiApp in RELEASE build, I encounter exception on UiApp, I have not debugged it.
I didn't investigate this failure in details before, but it might be related to a (bogus) device path installed into the efi image which is to be loaded into and invoked from the main memory.
-Takahiro Akashi
Regards, Masahisa Kojima
Thanks, Masahisa Kojima