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

["Andreas Färber" <afaerber@suse.de>]

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:
>>> On 04/04/2013 02:43 PM, Peter Maydell wrote:
>>>> The UI is all wrong, though:
>>>> -kernel should always mean "load a Linux kernel" and we should
>>>> have some other way (ideally a cross-architecture way) of saying
>>>> "just load this binary blob and start it". (-bios isn't that
>>>> because -bios tends to (a) mean different things on different
>>>> boards and (b) mean 'put this in flash or whatever' rather than
>>>> 'dump stuff in RAM and go'.)
>>>>
>>>
>>> I think -kernel works fine for all architecture. Linux is not the only
>>> kernel available ;)
>>
>> 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).

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

Regards,
Andreas

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