Re: [Qemu-devel] [PULL 2/4] bios: Add fast variant of SeaBIOS for use with -kernel on x86.

[Laurent Vivier]

Hi,

On 04/07/2016 11:33, Gerd Hoffmann wrote:
> From: "Richard W.M. Jones" <address@hidden>
> 
> This commit adds a fast variant of SeaBIOS called 'bios-fast.bin'.
> 
> It's designed to be the fastest (also the smallest, but that's not the
> main aim) SeaBIOS that is just enough to boot a Linux kernel using the
> -kernel option on i686 and x86_64.
> 
> This commit does not modify the -kernel option to use this.  You have
> to specify it by doing something like this:
> 
>   -kernel vmlinuz -bios bios-fast.bin

I like the idea: I'm wondering if we should do the same thing for ppc64?

In fact, it is already done, if you have kvm-unit-tests, you can do:

qemu-system-ppc64 ... -kernel vmlinuz \
                      -initrd initramfs.img \
                      -append .... \
                      -bios .../kvm-unit-tests/powerpc/boot_rom.bin

and boot_rom.bin is (thanks to the power of device-tree):

    #define SPAPR_KERNEL_LOAD_ADDR 0x400000
    .text
    .globl start
    start:
            b       SPAPR_KERNEL_LOAD_ADDR - 0x100

It can't be faster...

The question is: should we add this binary to qemu?

And it can open new doors: booting with petitboot instead of SLOF.

Laurent