[PATCH 0/9] efi_loader: rework bootefi/bootmgr

[AKASHI Takahiro]

Heinrich,

On Fri, Jan 03, 2020 at 01:17:05AM +0100, Heinrich Schuchardt wrote:
> On 4/19/19 5:22 AM, AKASHI Takahiro wrote:
> >There are several reasons that I want to rework/refactor bootefi command
> >as well as bootmgr:
> >* Some previous commits on bootefi.c have made the code complicated
> >   and a bit hard to understand.
> >
> >* do_bootefi_exec() would better be implemented using load_image() along
> >   with start_image() to be aligned with UEFI interfaces.
> >
> >* Contrary to the other part, efi_selftest part of the code is unusual
> >   in terms of loading/execution path in do_bootefi().
> >
> >* When we will support "secure boot" in the future, EFI Boot Manager
> >   is expected to be invoked as a standalone command without any arguments
> >   to mitigate security surfaces.
> >
> >In this patch set,
> >Patch#1 to #7 are preparatory patches for patch#8.
> >Patch#8 is a core part of reworking.
> >Patch#9 is for standalone boot manager.
> >
> ># Please note that some patches, say patch#2 and #3, can be combined into one
> ># but I intentionally keep them separated to clarify my intentions of changes.
> >
> >Issues:
> >* It would be better off to change the semantics of efi_dp_from_name().
> >no chance to free loaded_image_info->load_options. (see patch #8)
> >
> >-Takahiro Akashi
> 
> Hello Takahiro,
> 
> with the `efidebug boot add` command we can define load options for the
> BootXXXX variables.
> 
> But in do_efibootmgr() we call do_bootefi_exec() which calls
> set_load_options() and passes the value of environment variable bootargs
> as load options or if the variable is not set an empty string.
> 
> Here is an example console output:
> 
> => setenv bootargs This is a value from bootargs
> => efidebug boot add 0000 hello scsi 0:1 helloworld.efi 'This is a value
> from efidebug'
> => efidebug boot order 0000
> => bootefi bootmgr
> Booting: hello
> Hello, world!
> Running on UEFI 2.8
> Have SMBIOS table
> Have device tree
> Load options: This is a value from bootargs
> ## Application terminated, r = 0
> 
> Now the same after deleting variable bootargs:
> 
> => setenv bootargs
> => bootefi bootmgr
> Booting: hello
> Hello, world!
> Running on UEFI 2.8
> Have SMBIOS table
> Have device tree
> Load options: <none>
> ## Application terminated, r = 0
> =>

Yeah, this is not what I intended.

> What behavior would you expect:
> 
> a) if the boot option has a load options value,
> b) if the boot option has no load options value?
> 
> One solution would be to define that bootargs is always ignored if the
> boot manager is used.

I agree.
Basically, "bootargs" is only for "bootefi <addr>" command, while
"BootXXXX" should work in the exact same way as the UEFI specification
defines.

Thanks,
-Takahiro Akashi

> Best regards
> 
> Heinrich