[ipxe-devel] [PATCH] [efi] make load file protocol optional

[Gerd Hoffmann]

  Hi,

> > This issue might be fixable in several ways:
> > (a) Rework edk2 to provide EFI_PXE_BASE_CODE_PROTOCOL independently of
> >      EFI_LOAD_FILE_PROTOCOL.
> >
> > (b) Or, implement EFI_PXE_BASE_CODE_PROTOCOL in iPXE, and install it
> >      alongside EFI_LOAD_FILE_PROTOCOL, in efi_snp_probe().
> >
> > (c) Or, drop EFI_LOAD_FILE_PROTOCOL from step 2.1 (dependent on build
> >      time configuration).
> >
> > (d) Or, modify shim.efi, and possibly the other boot loader mentioned in
> >      step 1.5, to use EFI_LOAD_FILE_PROTOCOL. This would also require all
> >      relevant EFI_LOAD_FILE_PROTOCOL implementations to adhere to the
> >      FilePath parameter.
> >
> > Option (c) is by far the least intrusive, and the proposed patch does
> > that.
> 
> The problem is that option (c) also destroys the user's ability to use 
> most features of iPXE.  It's a quick hack rather than a solution.

I'm fine with using that as temporary stopgap only, until we have some
better solution.

> Option (d) sounds like the best idea, not least because it would allow 
> for the use of non-braindead network protocols (i.e. almost anything 
> except TFTP).  iPXE could quite easily have code in efi_snp_load_file() 
> which would open and autoconfigure the network device, interpret 
> FileName as a URI, and thereby allow shim.efi (or others) to download 
> files via HTTP, HTTPS, etc.

Pointless for the specific case of shim.efi (and see also Peter's
reply).  I don't think there a way around EFI_PXE_BASE_CODE_PROTOCOL, be
that the edk2 implementation or one provided by ipxe.

For grub.efi it certainly would make sense to use EFI_LOAD_FILE_PROTOCOL
to load files (maybe except grub.cfg), so one can have http urls in
grub.cfg and don't need to copy the kernels to tftproot when using ipxe.

cheers,
  Gerd