Re: grub-lnstall option (UEFI) for chainloading

[Daniel Kiper]

On Mon, Oct 12, 2015 at 11:08:24PM +0300, Andrei Borzenkov wrote:
> 12.10.2015 19:39, Daniel Kiper пишет:
> >On Mon, Oct 12, 2015 at 12:31:54PM +0300, Andrei Borzenkov wrote:
> >>On Tue, Sep 8, 2015 at 12:39 AM, Barry Jackson <address@hidden> wrote:
> >>>On 06/06/15 09:38, Andrei Borzenkov wrote:
> >>>>
> >>>>?? Fri, 05 Jun 2015 14:56:20 +0100
> >>>>Barry Jackson <address@hidden> ??????????:
> >>>
> >>>
> >>>>>Any progress on this?
> >>>>>
> >>>>
> >>>>
> >>>>Not really, sorry. Do you have any suggestion how such option should be
> >>>>named?
> >>>>
> >>>
> >>>Sorry for delay - this got lost in the noise.
> >>>
> >>>Well something like --no-id-or-nvram ??
> >>>
> >>>Not really bothered about the name! :)
> >>
> >>I was about to suggest a patch when I realized that this probably is
> >>currently useless on EFI. I.e. to actually chainload grub on EFI it
> >>must reside on a partition accessible by firmware which practically
> >>means it should be ESP.
> >>
> >>Unless someone submits patch to make grub2 EFI core.img multiboot2
> >>compliant with tag to skip ExitBootServices.
> >
> >Relevant patches waiting for review for months. I am working on v3.
> >If they are upstreamed I will be happy too.
> >
>
> Your patches implement "client side" support (loading MB2 images);

OK but they provide what you need here. So, it does not fully invalidate
what I said earlier.

> but EFI grub is not MB2 and has no provision for being loaded this
> way. Also it is PE, not ELF.

MB2 header may live in PE, ELF or even in file which does not have commonly 
known format.

> Actually chainloading probably could be made to work on arbitrary
> filesystem if argument parsing is added (to pass along cmdpath).

So, it looks that MB2 with my extensions should make it work.

Daniel