[SeaBIOS] [RFC 2/2] Add Linux boot code for the fw_cfg dma interface

Marc Marí markmb at redhat.com
Wed Aug 19 07:57:35 CET 2015


On Wed, 19 Aug 2015 00:27:54 +0200
Gerd Hoffmann <kraxel at redhat.com> wrote:

> On Di, 2015-07-21 at 18:06 +0200, Marc Marí wrote:
> > It's probably not good to override all the ROM options. Better ways
> > can be discussed.
> 
> source code for the option rom doing linux kernel (and multiboot
> kernel) boot is in pc-bios/optionrom/ (qemu tree).  Patching that one
> to use fw_cfg dma if available should get simliar speedups, but
> without compatiblity issues.
> 

The problem with patching the current ROMs, is that they are written in
assembly. So they would need a complete rewrite in C. Writing a DMA
guest in assembly I think it is a nightmare (but it can be done, of
course).

But it is true that I overlooked that point. I might get into this
change in the future.

Thanks
Marc



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