Re: [Qemu-devel] Machine specific option ROMs

[Gerd Hoffmann]

  Hi,

> > For example in qemu 1.5 the nic roms got EFI support and there is a
> > compat property which switches the pc-i440fx-1.4 (and older) machine
> > types to the non-efi versions.  Grep for pxe-e1000.rom to find the code.

Note that roms with a pci firmware standard header[1] can be chained
together, then placed in the pci rom bar.  This is how the efi-*.rom
files are created, they are three-in-one images (bios, efi ia32, efi
x64).

   # file pc-bios/qemu_vga.ndrv
   pc-bios/qemu_vga.ndrv: header for PowerPC PEF executable

Hmm, so that is probably not going to work.

> +static GlobalProperty compat[] = {
> +    { "VGA", "romfile", NDRV_VGA_FILENAME },
> +};

> +    compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat));

I wouldn't name the variable compat (in this specific case it's not for
backward compatibility), but yes, this is the idea.

> manually. (In the future this same way can also be used to pass proper 
> FCode ROMs to OpenBIOS.)

The image type (pci rom header) can be:

   Type      Description
   0         Intel x86, PC-AT compatible
   1         Open Firmware standard for PCI
   2         Hewlett-Packard PA RISC
   3         Extensible Firmware Interface (EFI) 
   4-FF      Reserved

So having a single pci rom image with both classic vgabios (type 0) and
open firmware fcode (type 1) should be possible.

cheers,
  Gerd

[1] http://read.pudn.com/downloads211/doc/comm/994029/pcifw_r3_0_updated.pdf, 
section 5.1