Re: or1k -M virt -hda and net.

[Rob Landley <rob@landley.net>]

On 1/8/25 07:01, BALATON Zoltan wrote:
> On Tue, 7 Jan 2025, Rob Landley wrote:
>> What's the alternative to -hda you suggest for that?
>>
>> Can I do "./run-qemu.sh -drive file=blah.img" without the rest? 
>> Perhaps specify all the details in the script and then optionally add 
>> an extra argument at the end? I couldn't get that to work:
>>
>> $ root/or1k/run-qemu.sh -netdev user,id=net0 -device virtio-net- 
>> device,netdev=net0 -drive format=raw,id=hd0 -device virtio-blk- 
>> device,drive=hd0 -drive file=README
> 
> You need '-drive if=none,id=hd0,format=raw,file=README' as a single 
> option not split into two.

I'm not always specifying an -hda. Sometimes it does, and sometimes it 
runs without it. I would like to have everything EXCEPT the media 
specified, so it can be inserted into a ready drive or run without it.

That's what -hda traditionally does.

> With if=none -drive won't auto-create a  device

$ root/or1k/run-qemu.sh -netdev user,id=net0 -device 
virtio-net-device,netdev=net0 -drive if=none,id=hd0,format=raw
qemu-system-or1k: -drive if=none,id=hd0,format=raw: A block device must 
be specified for "file"

> so you then also need a corresponding -device option for the 
> drive that you seem to have already above.

$ root/or1k/run-qemu.sh -netdev user,id=net0 -device 
virtio-net-device,netdev=net0 -device virtio-blk-device
qemu-system-or1k: -device virtio-blk-device: drive property not set
$ root/or1k/run-qemu.sh -netdev user,id=net0 -device 
virtio-net-device,netdev=net0 -device virtio-blk-device,drive=hd0
qemu-system-or1k: -device virtio-blk-device,drive=hd0: Property 
'virtio-blk-device.drive' can't find value 'hd0'
$ root/or1k/run-qemu.sh -netdev user,id=net0 -device 
virtio-net-device,netdev=net0 -device virtio-blk-device,drive=hd0 -drive 
id=hd0,if=none
qemu-system-or1k: -device virtio-blk-device,drive=hd0: Device needs 
media, but drive is empty

That's as close as I can get. As far as I can tell, it's complaining 
that I got it into the state I wanted, and it doesn't want to be in that 
state. The "if=none" does not appear to help.

I also don't know what drive=/id= pair "-hda" would be trying to 
populate, so dunno what name to use there.

Also, it requires -drive and its argument to be seperate:

   qemu-system-or1k: -device=virtio-blk-device,drive=hda: invalid option

Refusing to let them to be glued together with = (like most --longopt 
parsers do, including the 
https://github.com/landley/toybox/blob/master/lib/args.c I wrote) means 
I can't use bash's brace expansion to set up multiple at once (to 
preload support for -hda, -hdb, -hdc, and -hdd), ala:

   -drive=id=hd{0,1,2,3},if=none

Not that the current script has a bash dependency... :P

> If you want -hda to work you 
> may need something like commit d36b2f4e78 (hw/ppc/sam460ex: Support 
> short options for adding drives) for the machine you use. In particular 
> the MachineClass block_default_type field says what's the default 
> interface that -drive and other short options should use (at least I 
> think so, I'm no expert on this either but searching for it should at 
> least point to where it's handled).

Thanks for the pointer, I'll take a look.

Rob