Re: [Qemu-devel] [PATCH 3/3] PPC PReP: can run without bios image

[Fabien Chouteau <chouteau@adacore.com>]

On 04/04/2013 07:22 PM, Andreas Färber wrote:
> Am 04.04.2013 18:26, schrieb Artyom Tarasenko:
>> On Thu, Apr 4, 2013 at 6:20 PM, Peter Maydell <peter.maydell@linaro.org> wrote:
>>> On 4 April 2013 17:17, Fabien Chouteau <chouteau@adacore.com> wrote:
>>>
>>> But -kernel for QEMU specifically means Linux kernel; you might
>>> argue we should have picked a different option name but we're
>>> stuck with it now.
>>
>> No, it's not Linux-only. At least qemu-system-sparc can load NetBSD
>> kernel with this option.
>
> Look, you're not exactly making friends if you keep pointing out that
> something works somewhere and you try to deduce a rule out of that. ;)
>
> -bios loads something where the hardware expects it, not necessarily
> RAM. If using ELF, the entry point must be configured appropriately.
>
> -kernel loads something into RAM in a way a Linux kernel can run (and it
> does not limit itself to it, so other use cases may or may not work).
>

May I add the -pflash option to this list :)

> Loading something in a way that matches neither hardware nor Linux
> kernel is - for good or bad - simply not really supported at this time.
>
> PMM tried to get a discussion going about how to solve that latter case
> properly some months ago, possibly prompted by Xilinx, and there were
> not many responses, especially no concrete solution beyond vaguely
> pointing to devices/objects rather than fiddling with existing
> -kernel/-bios command line options.

I didn't see this discussion (there too many traffic on Qemu-devel for
me, I can't read everything).

> So I really feel this discussion is out of scope for this PReP patchset!

My goal with this patchset is to be able to load an ELF file and start
the board at its entry point. So we are exactly in the scope.

If the -kernel option is for Linux only, we have to rename it to -linux.
And we remove the ambiguous -kernel option. The question is: Do we want
a -bsd, -solaris, -vxworks, -rtems, etc...?

I think we can keep the -bios option (maybe with an -firmware alias,
this is a question of vocabulary of different architectures). But it
should be possible to disable the default bios, with '-bios -' or '-bios
none' or '-bios null' or '-bios disabled' or whatever.

And I make a proposition for new options:

-elf loads an ELF file in RAM, ROM or whatever memory area and start the
board at entry point.

-raw-bin file=<filename>,addr=0x<load address> loads something at 'addr'

Or we can mix the two with a -load option:

-load file=<raw-bin-file>
-load file=<elf-file>
-load file=<raw-bin-file>,addr=<load address>
-load file=<raw-bin-file>,addr=<load address>,entry=<start addr>

The option can be used as many times as needed on the command line.

-- 
Fabien Chouteau