[Nix-dev] uefi booting on nixos

[Mathijs Kwik]

Shea Levy <shea at shealevy.com> writes:

> On 3/18/12 7:18 AM, Mathijs Kwik wrote:
>> Shea Levy<shea at shealevy.com>  writes:
>>
>>> Hi Mathijs,
>>>
>>> It's not totally complete. In particular, the
>>> installRemovableMediaImage option installs an EFI program that is a)
>>> really hacky and b) depends on protocols not available on every
>>> firmware (though when they're not available the boot fails with no bad
>>> effects). I'm working with the kernel devs to ameliorate the problem
>>> that necessitated the hack in the first place. I also need to do more
>>> extensive testing, especially on the macbook pro. That being said, I
>>> have been using it exclusively on my desktop for the past week or so
>>> with several successful rebuilds, so there's that. If you do want to
>>> try it out, I recommend trying the latest ISO from
>>> http://hydra.nixos.org/job/nixos/trunk/iso_efi but if it doesn't boot
>>> in EFI mode boot it in BIOS mode for the install then, if your system
>>> supports efibootmgr, re-run switch-to-configuration after booting into
>>> the built system to install the boot manager entries.
>> EFI mode doesn't boot. The CD does show up as an UEFI boot option, but
>> if I select it, I get a very fast blue flash (grub menu ?),
>> followed by my installed (harddisk) grub starting (in bios mode).
>>
>> Should I just try to switch my running system to UEFI using
>> boot.loader.efiBootStub?
>> I guess I can always just boot my current BIOS/grub entry when it fails.
>>
>> I don't fully see how efibootstub would work, how does it plug in to
>> grub2_efi?
>
> It doesn't. Starting with Linux 3.3, the kernel itself is compiled as
> an EFI executable when the right option is set. So we don't need
> grub2_efi any more.

That's nice, one less layer sounds good.

>
>
>> As far as I know (at least on my system) efibootmgr cannot
>> communicate with the uefi when booted in bios mode, so I'm pretty sure I
>> need a working boot cd, or supply the bootmgr entry in the UEFI shell
>> myself. (I had to do that for grub2_efi on Arch)
>
> Right. You need to be in EFI mode, an EFI shell, or a firmware
> bootmanager interface in order to set a boot option. I'll be sure to
> document all this more clearly once it's closer to done :)

Ok, it finally works. I found a working UEFI shell for my hardware. It
was able to run startup.nsh and boot in efi mode.
There, efibootmgr was able to take over.
The only problem I still have is that efibootmgr points at the wrong
build sometimes (not the latest), so I need to change the order
manually.

Other than that, it's fine. Thanks a lot for your work.
I will give the newer livecd a shot sometime this week.

Mathijs

>
>>
>> Mathijs
>>
>>
>>> Let me know if you have any problems.
>>>
>>> Cheers,
>>> Shea
>>>
>>> On 3/16/12 4:34 PM, Mathijs Kwik wrote:
>>>> Hi Shea,
>>>>
>>>> I saw your commits dealing with uefi booting.
>>>> On my laptop, windows 7 boots fine from uefi.
>>>> However, linux doesn't. Grub-uefi boots, but something goes wrong
>>>> (memory mapping) when handig control to the kernel.
>>>> In the past, I've spent countless hours debugging it to no avail.
>>>>
>>>> I would like to give it another try someday soon.
>>>> Do you consider your uefi changes somewhat complete? Or do you still
>>>> have more changes planned?
>>>>
>>>> Anyway, thanks for your work.
>>>>
>>>> Mathijs