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

[Peter Maydell <peter.maydell@linaro.org>]

On 4 April 2013 17:34, Alexander Graf <agraf@suse.de> wrote:
> On 04.04.2013, at 18:30, Peter Maydell wrote:
>> * -kernel (if it means anything at all) has to mean "boot in
>> the way a Linux kernel expects and defines its boot protocol"
>
> This is what -kernel does. If more OSs than Linux end up happy with
> that interface, great. Examples for that are multiboot kernels on
> x86. But in general, kernels want to talk to firmware.

Agreed.

>> * "just load a binary and run it" needs to be some other option,
>> because that's not the same thing
>
> This is what -bios does. Maybe we should add an alias and call it
> "-firmware", but the idea stays the same. That's the initial blob
> executed when a VM gets up.

No, in general this isn't what -bios does. Usually -bios means
"take a blob and put it wherever this board expects to have
a ROM or flash firmware image". So on highbank it goes in the
sysram at 0xfff88000, on shix it's 0x4000 bytes loaded at address 0,
on mips_malta it's an image to load into a flash device, and
so on. And on some boards it does nothing at all, because we
ignore the parameter.

What is being asked for (and what ARM's -kernel does at the
moment if you pass it an ELF image) is "just load the ELF
image where the ELF image says to put it, and jump to the
ELF image's entrypoint".

-- PMM