Re: VW ELF loader

[Alexey Kardashevskiy]

On 04/02/2020 09:56, Paolo Bonzini wrote:
> 
> 
> Il lun 3 feb 2020, 23:36 Alexey Kardashevskiy <address@hidden
> <mailto:address@hidden>> ha scritto:
> 
> 
>     > What partition formats would have to be supported?
> 
>     MBR, GPT, is there anything else? "Support" is limited to converting a
>     number after command to [start, size] couple. I am not going for file
>     systems.
> 
>     > But honestly I'm
>     > more worried about the networking part.
> 
>     Fair enough.
> 
>     > Yes, SLOF is big and slow.  petitboot is not petit at all either, and
>     > has the disadvantage that you have to find a way to run GRUB
>     afterwards.
>     >  But would a similarly minimal OF implementation (no network,
>     almost no
>     > interpret so no Forth, device tree built entirely in the host, etc.)
>     > be just as big and slow?
> 
>     I doubt. We will be getting rid of unnecessary drivers, bus scanning
>     code (SCSI, PCI), device tree synchronization.
> 
> 
> What I mean is, if you write a firmware that exposes a minimal OF device
> interface but runs it in the guest, and does a hypercall for everything
> else, would it be as big and slow as SLOF?

I just did almost that - 20 bytes, fast as a bullet, runs in the guest ;)

Speaking seriously, what would I put into the guest?

The device tree? This is the core problem of the current design - we
need to keep it in sync with QEMU.

Netboot's dhcp/tftp/ip/ipv6 client? It is going to be another SLOF,
smaller but adhoc with only a couple of people knowing it. Other
packages - disk-label, deblocker - I do not see any user for these
except SLOF itself.


-- 
Alexey