Re: [PATCH v2 4/4] doc: qemu: arm: Add a section on booting Linux distros

[Alper Nebi Yasak <alpernebiyasak@gmail.com>]

On 2023-08-30 10:33 +03:00, Ilias Apalodimas wrote:
> Hi Alper,
> 
> On Sun, 27 Aug 2023 at 18:49, Alper Nebi Yasak <alpernebiyasak@gmail.com> wrote:
>>
>> On 2023-08-15 01:43 +03:00, Simon Glass wrote:
>>> Hi Alper,
>>>
>>> On Mon, 14 Aug 2023 at 11:40, Alper Nebi Yasak <alpernebiyasak@gmail.com> wrote:
>>>> I actually want to put the root.img device first so that the VM can boot
>>>> into the installed system when it reboots, but U-Boot can't find the
>>>> bootflow on the second drive. I tried e.g. `bootdev list -p; bootflow
>>>> scan -lab`, but it seems to only ever search the first virtio-blk.
>>>> However, `eficonfig; bootefi bootmgr` makes it boot somehow.
> 
> eficonfig, apart from displaying the boot options on a menu scans all
> media that have a simple filesystem protocol installed and configures
> the efi boot options.  That's why bootefi bootmgr boots properly
> afterwards.  You can probably boot even without eficonfig, but only
> bootXXX.efi files will be accounted for and no boot options will be
> added.
> 
> The EFI spec describes the bootmgr functionality in detail.  Back when
> the bootmeth patches were added, I suggested we shouldn't deal with
> EFI at all simply because it all already works and is backed by a
> spec.  Instead, we should just have a boot option in the methods that
> spells "EFI" and let the bootmanager deal with the details. But
> honestly, I've lost track of those patches.

I think bootflow and EFI should be different views on top of a single
"what can we do now that we are in U-Boot" model. IIUIC it's possible
for e.g. UEFI Shell to be built-in boot entries, so we could expose
bootflow entries (and more) similar to those? And EFI-based secondary
bootloaders like rEFInd could let us choose them in a graphical menu,
efibootmgr could change their order or reboot into a non-EFI flow...