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

[Glauber Costa <glommer@redhat.com>]

On Mon, Dec 14, 2009 at 04:01:43PM +0200, Michael S. Tsirkin wrote:
> On Mon, Dec 14, 2009 at 02:35:31PM +0100, Alexander Graf wrote:
> > Michael S. Tsirkin wrote:
> > > On Mon, Dec 14, 2009 at 12:55:28PM +0100, Alexander Graf wrote:
> > >   
> > >> Am 14.12.2009 um 11:59 schrieb "Michael S. Tsirkin" <mst@redhat.com>:
> > >>
> > >>     
> > >>> On Mon, Dec 14, 2009 at 11:16:34AM +0100, Gerd Hoffmann wrote:
> > >>>       
> > >>>> On 12/14/09 10:44, Michael S. Tsirkin wrote:
> > >>>>         
> > >>>>> No, it did not even start booting the kernel. Just gave me blank  
> > >>>>> screen.
> > >>>>>           
> > >>>> [ testing ]
> > >>>>
> > >>>> Oh.  That is something completely different.  A bug in the rom  
> > >>>> loader.
> > >>>> It fails to fit both e1000 (default nic) and virtio-net boot roms  
> > >>>> into
> > >>>> the option rom area and bails out (before loading seabios).  vl.c
> > >>>> doesn't check the return value and happily continues (without bios).
> > >>>> Which doesn't work out very well ...
> > >>>>
> > >>>> With two identical nics the (single) rom fits and qemu boots.
> > >>>>
> > >>>> Hmm.  Of course vl.c must be fixed to check the return value.
> > >>>>         
> > >>> Yes.
> > >>>
> > >>>       
> > >>>> Not sure how to deal with the rom size issue.  The gPXE roms look  
> > >>>> quit
> > >>>> big compared to the older roms we had.
> > >>>>         
> > >>> Hmm, it's a regression then ...
> > >>>       
> > >> How does real hw handle this? I'm pretty sure most servers these days  
> > >> use more option rom space than this. They usually have some onboard raid 
> > >> bios, external storage, on-board nic, pci nic, ...
> > >>     
> > >
> > > Real hardware might do several things I know about
> > > - option rom is typically small.
> > > - option rom is not loaded always (BIOS option), or not for all cards.
> > > There are might be other tricks.
> > >   
> > 
> > There are probably other tricks. I was booting up a machine that had
> > like 5 options roms going through their initialization that all weren't
> > exactly small.
> 
> This might boil down to better ROMs. E.g.
> maybe they request memory with PMM and then give it up
> after initialization?
That would be my guess.

However, gpxe rom are also used in real hardware. Maybe there
is some config trick we're missing?