Re: [PATCH v3] hw/i386: place setup_data at fixed place in memory

[Paolo Bonzini]

On 8/9/22 11:17, Michael S. Tsirkin wrote:
> > 1) if we believe "build setup_data in QEMU" is a feasible design that only
> > needs more yak shaving, we can keep the code in, but disabled by default,
> > and sort it out in 7.2.
> >
> > 2) if we go for an alternative design, it needs to be reverted.  For example
> > the randomness could be in _another_ fw_cfg file, and the linuxboot DMA can
> > patch it in the setup_data.
> >
> > With (2) the OVMF breakage would be limited to -dtb, which more or less
> > nobody cares about, and we can just look the other way.
>
> So IIUC you retract your pc: add property for Linux setup_data random
> number seed then? It's neither of the two options above.

That one would be a base for (1).

Another choice (3) is to put a pointer to the first setup_data in a new 
fw_cfg entry, and let the option ROMs place it in the header.

In any case, as Laszlo said this [PATCH v3] does not work because 
0xf0000 is mapped as ROM (and if it worked, it would have the same 
problem as the first 640K).

Paolo