[Qemu-devel] vgabios + qemu: issues and plans.

[Gerd Hoffmann <kraxel@redhat.com>]

   Hi,

Today we have two vgabios versions in qemu:  The standard one 
(vgabios.bin) and the cirrus one (vgabios-cirrus.bin).

The cirrus vgabios is a PCI ROM.  We can (and do) load it into the ROM 
PCI bar.  The vgabios checks the pci config space to figure where the 
linear framebuffer (for vesa graphics) is mapped to.  It knows how to 
program the cirrus.

The standard bios isn't a PCI ROM.  We have to load it using the seabios 
firmware interface.  It expects to find the linear framebuffer at the 
magic address 0xe0000000.  It uses the bochs extentions to implement 
vesa graphics support.

So, what is wrong with this?

First, I'd like to be able to load the vgabios via PCI ROM bar on all 
pci vga cards (stdvga, vmware, soon qxl).  The PCI ID in the bios has to 
match the PCI ID of the card, so we'll need a bunch of vga bios 
binaries, all identical except for the PCI ID.  Or we need some kind of 
binary patching.  Otherwise seabios will not load them from the PCI ROM bar.

Second, I want to get rid of the magic address 0xe0000000 (except for 
isa-vga).  This is basically just a matter of updating to vgabios 
version 0.6c.  And this needs one vga bios binary per vga card too as 
the PCI ID is used to lookup the card (and then the framebuffer address) 
in PCI config space.

Comments?  Especially on the binary patching?  Worth it?  Or just build 
a bunch of binaries?  They are not *that* big after all ...

cheers,
   Gerd