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Date: Thu, 28 Jan 2010 15:50:46 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: [Qemu-devel] Re: future of the virtio-blk serial number support
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To: Christoph Hellwig <hch@lst.de>
Cc: john cooper <john.cooper@redhat.com>, Christian Borntraeger <borntraeger@de.ibm.com>, Anthony Liguori <aliguori@us.ibm.com>, Rusty Russell <rusty@rustcorp.com.au>, qemu-devel@nongnu.org

On Thu, Jan 28, 2010 at 01:43:27PM +0100, Christoph Hellwig wrote:
> Back iSeptember 2007 Michael made the serial number support in qemu
> optional and off by default, and in October 2009 Rusty reverted the
> Linux virtio-blk support for it.  Given that I can't find support in
> any other virtio implementation that makes the feature look essentially
> dead.
> 
> How should we proceed with adding more fields to struct virtio_blk_config?
> I would suggest removing the identity field, declaring
> VIRTIO_BLK_F_IDENTIFY officially deprecated and adding the new fields
> directly after blk_size again, maybe with a comment that these new
> features can't be advertized together with VIRTIO_BLK_F_IDENTIFY.
> 
> I need to add a new optiomal_io_size field soon to support the block
> topology information when using virtio which is quite important when
> using RAID arrays as backend, and I'd prefer to do it in a way that's
> compatibly with the PCI spec.


Makes sense to me.