[Qemu-devel] How linux kernel is directly loaded?

[Qemu-devel] How linux kernel is directly loaded?

[Thakur]

Hi,

I was searching for code in qemu which is directly able to load linux
kernel with -k option. Which file implements it? Can someone point me to
location where this load process is described? My objective is to load
the Minix kernel in same fashion.

Thanks

Best Regards
- Thakur

Re: [Qemu-devel] How linux kernel is directly loaded?

[Blue Swirl]

On 2/1/09, Thakur <thakur@symmetricore.com> wrote:
> Hi,
>
>  I was searching for code in qemu which is directly able to load linux
>  kernel with -k option. Which file implements it? Can someone point me to
>  location where this load process is described? My objective is to load
>  the Minix kernel in same fashion.

For PC architecture, it's done in hw/pc.c. There are ELF, a.out and
binary load functions available, if you need them for Minix.

Re: [Qemu-devel] How linux kernel is directly loaded?

[Thakur]

On Sun, 2009-02-01 at 16:51 +0200, Blue Swirl wrote:
> On 2/1/09, Thakur <thakur@symmetricore.com> wrote:
> > Hi,
> >
> >  I was searching for code in qemu which is directly able to load linux
> >  kernel with -k option. Which file implements it? Can someone point me to
> >  location where this load process is described? My objective is to load
> >  the Minix kernel in same fashion.
> 
> For PC architecture, it's done in hw/pc.c. There are ELF, a.out and
> binary load functions available, if you need them for Minix.
> 
> 

I don't have much knowledge of internals of qemu. I know how u-boot
loads the linux kernel, so  I was searching for similar pattern. :) How
does qemu know the entry point of the kernel?

Thanks

Regards
- Himanshu

Re: [Qemu-devel] How linux kernel is directly loaded?

[Anthony Liguori]

Thakur wrote:
> Hi,
>
> I was searching for code in qemu which is directly able to load linux
> kernel with -k option. Which file implements it? Can someone point me to
> location where this load process is described? My objective is to load
> the Minix kernel in same fashion.
>   

It's different for every architecture but since you're interested in 
Minix, I assume you're interested in x86.

The important bits are in hw/pc.c:load_linux().

Currently, the way this is implemented is by loading the kernel into 
memory and creating a tiny option rom that hijacks int19.  int19 is the 
BIOS boot interrupt so this allows us to run our own tiny boot loader 
that loads the kernel that we previously loaded into memory.

Depending on how different the Minix boot protocol is, it should be 
relatively easy to adapt.

Regards,

Anthony Liguori

> Thanks
>
> Best Regards
> - Thakur
>
>
>
>