Re: [Qemu-devel] [PATCH V7 23/24] apci: fix PXB behaviour if used with unsupported BIOS

[Marcel Apfelbaum]

On 06/01/2015 03:27 PM, Michael S. Tsirkin wrote:
> On Mon, Jun 01, 2015 at 03:21:19PM +0300, Marcel Apfelbaum wrote:
> > On 06/01/2015 03:17 PM, Michael S. Tsirkin wrote:
> > > On Mon, Jun 01, 2015 at 01:40:19PM +0200, Gerd Hoffmann wrote:
> > > > On Mo, 2015-06-01 at 12:44 +0300, Marcel Apfelbaum wrote:
> > > > > On 05/31/2015 09:12 PM, Michael S. Tsirkin wrote:
> > > > > > On Mon, May 25, 2015 at 06:34:01PM +0300, Marcel Apfelbaum wrote:
> > > > > > > PXB does not work with unsupported bioses, but should
> > > > > > > not interfere with normal OS operation.
> > > > > > > We don't ship them anymore, but it's reasonable
> > > > > > > to keep the work-around until we update the bios in qemu.
> > > > > >
> > > > > > We already did, did we not?
> > > > > Yes, we did, but Gerd preferred to keep this patch around.
> > > > > Adding him to thread.
> > > >
> > > > seabios bundled with qemu isn't the only possible firmware.
> > > >
> > > > We have ovmf, coreboot, qboot.
> > >
> > > ovmf is especially interesting. Marcel, did you look at what
> > > happens with pxb and ovmf?
> > No, I talked to Laszlo about it, he said ovmf is not there yet.
> > OVMF will not query the extra buses, so the devices on the extra bus will not 
> > be visible.
> > Adding him to the thread.
> >
> > Thanks,
> > Marcel
>
> But does OVMF need this specific patch?
I don't think so because more than likely it doesn't scan for the extra buses,
so it will not try to configure these devices.
Laszlo, am I right?

Thanks,
Marcel

> > > > You might boot with old seabios for
> > > > whatever reasons (say bisecting down something).
> > >
> > > But then you won't have pxb, will you?
> > >
> > > > IMO qemu should deal
> > > > with pxe not being initialized by the firmware in a sensible way, for
> > > > robustness reasons.
> > > >
> > > > cheers,
> > > >    Gerd