Re: [Qemu-devel] [PATCH] CMOS file support

[Mathias Krause <mathias.krause@secunet.com>]

Am 16.09.2010 18:49, Stefan Weil schrieb:
> The intention of this patch is ok. Loading CMOS with initial data
> is needed. I just want to add two questions / remarks how the
> implementation might be improved.
> 
> Are there use cases where having a smaller CMOS size is better?
> For example, when I want to emulate a system with 128 byte CMOS?
> The size of CMOS could be derived from the size of the data
> or specified by an additional parameter.

I cannot image cases where smaller sizes would be a benefit. The saved
disk space is negligible and you can always pad your CMOS configuration
uo to 256 bytes by filling the gap with zero bytes. If the system just
accesses the first 128 bytes the additional 128 zero bytes shouldn't hurt.

> Using QEMU's block devices instead of a simple file would be
> more consistent with the rest of QEMU and allow reading the
> CMOS data not only from a file but also from an URL or other
> sources.

Thanks for the hint. Since this is my first contribution to the project
I'm not that familiar with the code. Looking at other places, e.g. how
the -kernel option gets handled, I just see FILE everywhere. Can you
give me some pointers how to use this interface?

Thanks for the review!


Mathias