Re: [Qemu-devel] Re: qdev property bug?

[Michael S. Tsirkin]

On Mon, Dec 14, 2009 at 08:12:48PM +0100, Sebastian Herbszt wrote:
> Anthony Liguori wrote:
>> Michael S. Tsirkin wrote:
>>>
>>> Further, we should error out when device is added.
>>> Doing this during boot is way too late, management
>>> won't be able to understand such errors and
>>> won't be able to recover.
>>>   
>>
>> I don't quite understand this.
>>
>> In 0.11, we never loaded option roms unless a user specified -boot n.   
>> If a user specified -boot n and used more than one nic type, I'm fairly 
>> certain it would error out during start up because it would run out of  
>> option rom space.  Maybe it required three types of nics, but the point 
>> still remains.
>
> I think it used to be possible to have two different nic types and only load
> one rom, e.g. -net nic,model=pcnet -net nic,model=e1000 -option-rom e1000.rom
> Then use the boot menu to select the e1000 nic.
>
>> In 0.12, we always load the option rom for a PCI device.  An easy  
>> solution here would be to just gracefully handle the case where we ran  
>> out of option rom space and (silently) stop loading additional roms.   
>> With respect to -boot n, it makes the behavior buggy (you cannot boot  
>> from the second nic) but my original point is that that is not a  
>> regression from 0.11.
>
> Even if i repeat myself [1] i suggest putting an option-rom loading flag to 
> the -net option:
> -net nic,model=e1000,rom=[on,off,e1000.bin]
>
>> For 0.13, we should probably allow a user to suppress option rom 
>> loading for a given PCI device.  The limited space is a pretty good  
>> justification for that.
>
> The default behaviour should be not loading option-roms; users should request 
> those.
>
> [1] http://lists.gnu.org/archive/html/qemu-devel/2009-11/msg01095.html
>
> - Sebastian

I am not sure I agree. This is common for PXE and I think
makes sense there, but I think this might not
make sense for VGA rom or e.g. scsi.


-- 
MST