Re: [Qemu-devel] [PATCH v8 0/2] PC system flash support

[Avi Kivity <avi@redhat.com>]

On 11/29/2011 09:03 AM, Jordan Justen wrote:
> On Mon, Nov 28, 2011 at 02:28, Avi Kivity <avi@redhat.com> wrote:
> > On 11/28/2011 04:26 AM, Jordan Justen wrote:
> >> Enable flash emulation in a PC system using pflash_cfi01.
> >
> > The new memory layout should be made conditional on the machine type (-M
> > pc-1.1 or later) to allow migration from/to pc-1.0 and earlier.
> >
> > Memory layout in this context are the names of memory ranges given to
> > memory_region_init_ram(), sizes, and locations.  Also, the flash
> > interface should not be there for older machines.
>
> Is this the right way to go about it?
> 1. Create a new pc-sysfw qdev
> 2. Use a flash property in pc_piix.c to selectively enable the flash
>
> Or, is there an easier or better way to say pc > pc-1.0?

No idea, copying some qdev people.

> How do I enable "migration from/to pc-1.0 and earlier"?  It seems like
> some code will need to shuttle the data (rom <=> pflash).  Can you
> point me an an example?

It should be completely transparent, so long as you instantiate a ROM
for <= pc-1.0 (say based on a property) and flash for >= pc-1.1.

One way to verify is to to 'info qdev' and 'info mtree' with qemu-1.0
and qemu-1.1 -M pc-1.0, and see that you get the same results.

-- 
error compiling committee.c: too many arguments to function