Re: [Qemu-devel] [PATCH 0/5] boot order specification

[Gleb Natapov <gleb@redhat.com>]

On Tue, Oct 26, 2010 at 05:00:25PM +0000, Blue Swirl wrote:
> On Tue, Oct 26, 2010 at 3:43 PM, Gleb Natapov <gleb@redhat.com> wrote:
> > On Tue, Oct 26, 2010 at 03:35:38PM +0000, Blue Swirl wrote:
> >> On Tue, Oct 26, 2010 at 10:48 AM, Gleb Natapov <gleb@redhat.com> wrote:
> >> > This is current sate of the patch series for people to comment on.
> >> > I dropped ioport double reservation checking from isa-bus and added
> >> > bus_id field for IDE bus since as Markus pointed out unit has different
> >> > meaning there.
> >> >
> >> > This patch series produce names like:
> >> >
> >> > ISA@03f1-03f5,03f7/fd@a
> >> > ISA@03f1-03f5,03f7/fd@b
> >> > PCI@0000:00:01.1/IDE@1:0
> >> > PCI@0000:00:01.1/IDE@1:1
> >> > PCI@0000:00:03.0/virtio-blk@0
> >> > PCI@0000:00:04.0/virtio-net@0
> >> >
> >> > They will be passed to BIOS to determine boot order.
> >>
> >> We also use OpenBIOS for PPC and Sparcs. A compatible boot device for
> >> those would be OpenFirmware tree name. I think your names should then
> >> become:
> >> /pci/isa/fdc@3f1/fd@0
> >> /pci/isa/fdc@3f1/fd@1
> > Why is it PCI?
> 
> I just assumed a PCI to ISA bridge.
> 
> >> /pci/ide@0/1,0
> >> /pci/ide@0/1,1
> > Where pci address here?
> >
> >> /pci/virtio-net@1
> >> /pci/virtio-net@2
> > And here?
> 
> That was the part I invented.
> 
> > And we will need to describe ROMs too. I planned to have something like:
> > ROM@romfilename for roms loaded with -option-rom command line option.
> 
> I don't think OF has standard for those.
> 
> >>
> >> The PCI addressing scheme in OF was a bit twisty, I just invented
> >> integers in place of those.
> >>
> >> Anyway, I don't think we should invent yet another device path naming system.
> > IS this format documented somewhere? I am not attached to specific
> > format at all.
> 
> A lot of docs are here:
> http://playground.sun.com/pub/p1275/home.html
Search for flat, device or tree returns nothing on this page.

But looking elsewhere I found some description of DTS. It is very
elaborate and looks like this:

/pci@xxx {
plenty of info here
}

The only example of /pci@xxx that I found is here
http://wiki.freebsd.org/FlattenedDeviceTree but not any spec about its
format.

> 
> Here's the PCI bindings doc:
> http://playground.sun.com/pub/p1275/bindings/pci/pci2_1.pdf
The funny thing is that pci address used in /pci@ example from wiki
above is incorrect according to this spec.

And I thought ACPI spec is confusing :) Can you clarify things a little
bit please?

--
			Gleb.