[Qemu-devel] [PATCH 00/10] scsi: add specialized block device passthrough

[Paolo Bonzini <pbonzini@redhat.com>]

This series adds a new scsi-block device that is able to do SCSI
passthrough for block devices only, but at the same time does not suffer
the limitations of scsi-generic.  In particular it does not need a
bounce buffer that is as big as the request, and will be able to support
s/g lists.  This puts scsi-block and virtio-blk on feature parity.

To do this, scsi-generic is simplified to the point that its ReqOps can be
used by any SCSIDevice.  Then, a new scsi-disk variant is introduced that
uses regular AIO read/writes whenever possible, and falls back to SG_IO
for other SCSI commands.  Management can then choose between isolating
the guest from the specificities of the target device (scsi-hd/scsi-cd),
or making it aware of them (scsi-block).

In the future, both scsi-generic and scsi-block could be made to support
other types of passthrough, for example iSCSI passthrough.

Patches 1-4 are cleanups to scsi-generic, patches 5-6 are cleanups
to scsi-disk.  Then comes the actual implementation of the feature.

Paolo Bonzini (10):
  scsi-generic: drop SCSIGenericState
  scsi-generic: remove scsi_req_fixup
  scsi-generic: check ioctl statuses when SG_IO succeeds
  scsi-generic: look at host status
  scsi-disk: do not duplicate BlockDriverState member
  scsi-disk: small clean up to INQUIRY
  scsi: make reqops const
  scsi: export scsi_generic_reqops
  scsi: pass cdb to alloc_req
  scsi-disk: add scsi-block for device passthrough

 hw/scsi-bus.c     |   12 ++--
 hw/scsi-disk.c    |  260 +++++++++++++++++++++++++++++++++++++---------------
 hw/scsi-generic.c |  128 ++++++++++++---------------
 hw/scsi.h         |   12 ++-
 4 files changed, 255 insertions(+), 157 deletions(-)

-- 
1.7.6