Re: [Qemu-devel] [PATCH 1/3] spapr: allow creating devices with -device

[Markus Armbruster]

Paolo Bonzini <address@hidden> writes:

> On 05/24/2011 03:03 PM, Markus Armbruster wrote:
>> >  This is particularly important with the conversion from scsi-disk
>> >  to scsi-{cd,hd} that Markus made.  After his patches, if you
>> >  specify a scsi-cd device attached to an if=none drive, the default
>> >  VSCSI controller will not be created and, without qdevification,
>> >  you will not be able to add yours.
>>
>> Really?  Hasn't that always been the case?
>
> What hasn't always been the case? :)
>
> 1) "the default VSCSI controller will not be created" -- no, this is
> new with scsi-cd: scsi-disk never was on the default_driver_table in
> vl.c, as you said in the commit message for af6bf13 (defaults: ide-cd,
> ide-hd and scsi-cd devices suppress default CD-ROM, 2011-05-18).  In
> fact, I believe you could add scsi-hd there too.

Aha.  The default CD-ROM also creates a default controller if
machine->use_scsi.  But as soon as you try -device scsi-cd, it
vanishes.  Hmm.

> 2) "without qdevification, you will not be able to add yours" -- that
> of course has always been the case.  But I never noticed because there
> was no way to avoid creating the default CD-ROM, and this in turn
> forced the non-qdev-clean creation of the VSCSI controller.

There's -nodefaults.