On 01/28/2010 06:43 AM, 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.
Sounds good to me. IDENTIFY is basically impossible to implement in
it's current form with virtio-pci.
We should put something in the spec mentioning that config space is
limited and large values should not be placed in it. Instead,
implementations should use a control ring queue to pass large data sets.
Regards,
Anthony Liguori
