Re: [Qemu-devel] [PATCH v4] hw/pc: Support system flash memory with -pflash parameter

[Anthony Liguori <anthony@codemonkey.ws>]

On 07/23/2011 07:18 PM, Jordan Justen wrote:
>> In terms of other flash devices, I don't think it's that simple.  Flash is
>> tied to the mobo layout so I don't think index>  0 really makes sense unless
>> you allow a specific mapping address.  I doubt that's terribly useful.
>
> I think VM's have a different situation than real hardware.  I'm not
> sure an all ROM or all flash decision will work well for qemu.  In
> most cases it may work better to make a ROM image available just below
> 4GB, and add a flash image below this ROM.
>
> This allows the qemu's firmware to be updated as usual in
> ${prefix}/share/bios.bin, but still allows a flash memory to be
> available below this.  (The flash below the ROM could be used only for
> storing UEFI variables.)
>
> Otherwise when a new qemu is released along with a new firmware image,
> the VM instance using writable flash will continue to use the old
> firmware image.

Yes, that's a feature.

We could have a second nvram for other purposes of course.  That could 
be defined as index=1.

Regards,

Anthony Liguori