Re: or1k -M virt -hda and net.

[Stafford Horne <shorne@gmail.com>]

On Tue, Jan 07, 2025 at 05:56:52AM -0600, Rob Landley wrote:
> On 12/31/24 19:19, Rob Landley wrote:
> > On 12/23/24 07:05, Stafford Horne wrote:
> > > > The kernel config looks like it should have virt block device
> > > > support, but
> ...
> > >    -device virtio-blk-device,drive=d0 -drive
> > > file=${DISK},id=d0,if=none,format=qcow2
> > 
> > -drive file=file.img,format=raw,id=hd0 -device virtio-blk-device,drive=hd0
> > 
> > My -device looks similar but -drive is file=file.img,format=raw,id=hd0
> > 
> > No idea what if= does? I haven't seemed to need it...
> ...
> > Thanks, I think this target is good for release. Now to figure out why
> > sh2eb network isn't working after the restore (it used to!). Nor is
> > microblaze's network...
> 
> My test harness appends -hda filename.img to the qemu command line, which
> works for all the other targets, and is awkward to turn into
> -device lots-of-stuff,file-filename.img,more-stuff inside a shell script.
> (At best it's a special case parsing and rewriting qemu command line
> plumbing to turn "generic" into an architecture-specific workaround.)

Hi Rob,

Sorry, from the laat email I was under the impression that you had everything
working as expected.

> In THEORY I should be able to do something like:
> 
> root/or1k/run-qemu.sh -netdev user,id=net0 -device
> virtio-net-device,netdev=net0 -device virtio-blk-device,drive=sd0 -hda
> README
> 
> And just have extra arch setup that then accepts the generic appended to it.
> But in practice that says:
> 
> qemu-system-or1k: -device virtio-blk-device,drive=sd0: Device needs media,
> but drive is empty
> 
> Putting the -hda before the -device doesn't help. (And even if it did, the
> result would barf if run _without_ -hda, which should also work.)
> 
> Having -hda by itself is accepted by qemu, but I don't know what bus/driver
> gets added as a result (or1k kernel does not find it).

I am having a hard time understanding the use case.

As you know I use the following to wire in the buildroot image which I turned
into a qcow2 disk using my tool:

  https://github.com/stffrdhrn/or1k-utils/blob/master/scripts/qemu-or1k-mkimg

  -device virtio-blk-device,drive=d0 -drive file=${DISK},id=d0,format=qcow2

But I think you want to use:

  -device virtio-blk-device,drive=sd0 -hda XYZ

I have not used -hda before, do you have it working with other targets?

According to the qemu docs in qemu-options.hx. I see:

    Use file as hard disk 0, 1, 2 or 3 image on the default bus of the
    emulated machine (this is for example the IDE bus on most x86 machines,
    but it can also be SCSI, virtio or something else on other target
    architectures). See also the :ref:`disk images` chapter in the System
    Emulation Users Guide.

I think, since we don't have a "default" bus in openrisc this doesn't work so we
need to specify the -drive explictly.

I checked the x86 machine code and confirm it seems to work like this.  There is
code in the system setup to look for hd* drives and wire them into IDE.  There
is no such code in openrisc.

-Stafford