Re: [Qemu-devel] [PATCH 2/5] virtio-blk: disable scsi passthrough for 1.0 device

[Paolo Bonzini <pbonzini@redhat.com>]

On 13/07/2015 16:41, Cornelia Huck wrote:
> On Mon, 13 Jul 2015 16:34:30 +0200
> Paolo Bonzini <pbonzini@redhat.com> wrote:
>> On 13/07/2015 15:20, Cornelia Huck wrote:
>>> This would imply that any transitional device cannot offer scsi,
>>> doesn't it?
>>>
>>> We have two layers interacting here: virtio-blk which may or may not
>>> offer scsi support, and the transport layer which may or may not offer
>>> VERSION_1 support. Failing scsi commands if VERSION_1 has been
>>> negotiated makes sense to me; but I don't want to disable scsi config a
>>> priori because the driver might negotiate VERSION_1. This would imply
>>> that virtio-blk over virtio-ccw would never offer scsi once we enable
>>> virtio-1 support, and it kind of defeats the purpose of a transitional
>>> device for me.
>>>
>>> (The other way round - fail negotiating revison 1 if the device was
>>> configured with scsi support - makes more sense to me.)
>>
>> For newer machine types, it would make sense to block VIRTIO_BLK_F_SCSI
>> altogether if !blk->conf.scsi.  Would that fix the problem for you too?
> 
> This is probably a sensible approach, and it can be contained in
> virtio-block, no?

Yes, I think so.

Paolo