Re: [Qemu-devel] [RFC PATCH 5/7] vl.c: added -kerndtb option

[Anthony Liguori]

On 01/24/2012 12:23 PM, Stefan Weil wrote:
> Am 24.01.2012 08:22, schrieb Andreas Färber:
> > Am 23.01.2012 08:20, schrieb Peter A. G. Crosthwaite:
> > > Added linux specific kernel dtb option. This option can be specified to inject
> > > an argument device tree blob (dtb) into linux.
> > >
> > > Signed-off-by: Peter A. G. Crosthwaite <address@hidden>
> > > ---
> > > qemu-options.hx | 3 +++
> > > vl.c | 4 ++++
> > > 2 files changed, 7 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/qemu-options.hx b/qemu-options.hx
> > > index 6295cde..43cddff 100644
> > > --- a/qemu-options.hx
> > > +++ b/qemu-options.hx
> > > @@ -1931,6 +1931,9 @@ ETEXI
> > >
> > > DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
> > > "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
> > > +DEF("kern-dtb", HAS_ARG, QEMU_OPTION_kerndtb, \
> > > + "-kern-dtb dtb device tree blob passed to kernel boot\n", QEMU_ARCH_ALL)
> >
> > We should probably call it -kernel-dtb. If there's some strncmp() from
> > -kernel interfering, we should fix that instead.
> >
> > I don't see this variable being used anywhere in this series though.
> > Would it have been in the missing zynq machine of 7/7?
> >
> > Andreas
>
> I'd prefer a different solution. As far as I have understood,
> the dtb is only useful with a kernel, so it could be handled
> as an optional attribute to the -kernel parameter:
>
> -kernel IMAGE[,dtb=DTB]

If it looks like a device, acts like a device, and smells like a device...

The best thing to do here is to make an arm-kernel-loader device that hangs off 
of sysbus and takes four string properties.

I was going to do this shortly for PC anyway.

BTW, for unknown command line options, we should probably assume they are 
-device and treat accordingly.  So -arm-kernel-loader 
dtb=DTB,kernel=/path/to/vmlinux would Just Work.

Regards,

Anthony Liguori

> Of course the same applies to -append, but that's a different issue.
>
> Regards,
> Stefan