Re: [Qemu-devel] [PATCH] turn firmware image filename into a machine option

[Anthony Liguori]

On Tue, Oct 1, 2013 at 10:28 AM, Paolo Bonzini <address@hidden> wrote:

Il 01/10/2013 17:12, Peter Maydell ha scritto:

>> > I just need some way to have different default firmware images for
>> > different pc machine type versions.  Requests to considering other
>> > firmware loading needs (such as the two images needed for sPAPR) when
>> > doing this is reasonable.  Blaming me for how inconistent qemu's
>> > firmware loading is today is not ok.
> You're defining new command line syntax -- it seems reasonable
> to think about what it ought to actually mean rather than just
> saying "it should mean the same collection of random stuff
> that -bios means". If you're going to do that you should just stick
> with -bios...

What it ought to mean could be "the ROM that bootstraps the machine by
loading stuff from a drive (could be NAND, SD or a hardware component
such as virtio/IDE/SCSI)".  But most machines sidestep this by loading
the kernel directly in RAM.

Firmware should not be a special concept in QEMU but it is.  On real hardware, the firmware is stored in some sort of memory device that happens to be addressed at a specific location.  This should be modelled as we do with -pflash as a block device and a ROM device.

But we have a world today where firmware is special so we need to deal with that.  And since the vast majority of systems have exactly one firmware blob, we should model the 99% case and let folks figure out how to deal with the remaining 1%.

BTW, sPAPR is never a good reason to change how something is modelled.  It is not a hardware system.  It's a virtual machine.  The concepts it has are not going to cleanly relate to other systems and RTAS is a very good example of this.  RTAS has more in common with Linux's VDSO than anything on real hardware.

Regards,

Anthony Liguori

 

Paolo