Re: Proper support for PCI-based option rom loading (was Re: [Qemu-devel] Re: qdev property bug?)

[Sebastian Herbszt]

Anthony Liguori wrote:
> Michael S. Tsirkin wrote:
> > > I think it's stable-0.12 material because it's badly broken right now  
> > >     
> >
> > I thought the rule was no guest visible changes in stable series?
> >   
>
> Yeah, good point, so we need to figure out something for 0.12.0.
>
> Sebastian's suggestion of loading roms from 0xc0000 first and then from 
> PCI devices is a good one, but I think the problem with that is that the 
> roms don't necessarily have to be contiguous in that space.  For 
> instance, the lower bios portions are technically in the rom area which 
> leaves a big gap in the middle.

I don't think i get your objection - mind to explain it a little bit?
My suggestion was like this:
PCI pc and -option-rom rom1.bin -option-rom rom2.bin

Qemu will map rom1.bin to PC_ROM_MIN_OPTION (0xc8000) and map rom2.bin
to 0xd0000. Either qemu will map vga bios to PC_ROM_MIN_VGA (0xc0000) or
SeaBIOS will map it there (with pci 3.0 it could map it somewhere else, but i 
doubt thats
a good idea). In case the vga bios size is below 0x8000, some rom space is 
lost. SeaBIOS
will scan the option rom space starting at PC_ROM_MIN_OPTION and adjust its 
RomEnd in
case a rom is found. Then it will start the pci scan and map pci option roms 
after RomEnd.

- Sebastian