Re: [Qemu-devel] [PATCH] Revert "virtio_rng: replace custom backend API with UserCreatable.complete() callback"

[Markus Armbruster <armbru@redhat.com>]

Stefan Hajnoczi <stefanha@gmail.com> writes:

> On Sat, Aug 16, 2014 at 12:23:52AM +0800, Amos Kong wrote:
>> This reverts commit 57d3e1b3f52d07d215ed96df946ee01f8d9f9526.
>> 
>> The commit introduced a regression bug, the initialization order of virtio-rng
>> backend was changed.
>> 
>>  # x86_64-softmmu/qemu-system-x86_64 -monitor stdio -vnc :0 \
>>      -chardev socket,host=localhost,port=1024,id=chr0 \
>>      -object rng-egd,chardev=chr0,id=rng0
>> 
>>  qemu-system-x86_64: -object rng-egd,chardev=chr0,id=rng0: Device 'chr0' not found
>> 
>> Chardev 'chr0' isn't initialized when we try to open rng backend,
>
> More detail:
> The problem is that vl.c:main() calls object_create() on -object before
> -chardev options are processed.  Moving the object_create() call after
> chardev is arbitrary and does not work if a chardev depends on an
> -object.
>
> It would have been nice to process command-line options in left-to-right
> order instead of grouping them by option type.  I doubt we can change
> this now since it would break the command-line.

In my private opinion, our command line could really use a thorough
breaking.

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