[Qemu-devel] [PATCH for-2.2 0/5] scsi: enable passthrough of vendor-specific commands

[Paolo Bonzini]

Right now scsi-generic is parsing the CDB, in order to compute
the expected number of bytes to be transferred.  This is necessary
if DMA is done by the HBA via scsi_req_data, but it prevents executing
vendor-specific commands via scsi-generic because we don't know how
to parse them.

If DMA is delegated to the SCSI layer via get_sg_list, we know in
advance how many bytes the guest will want to receive and we can pass
the information straight from the guest to SG_IO.  In this case, it is
unnecessary to parse the CDB to get the same information.  scsi-disk needs
it to detect underruns and overruns, but scsi-generic and scsi-block can
just ask the HBA about the transfer direction and size.

This series introduces a new parse_cdb callback in both the device and
the HBA.  The latter is called by scsi_bus_parse_cdb, which devices can
call for passthrough requests in their implementation of parse_cdb.

Tamuki-san, can you please test if these patches are okay for your
usecase?

Paolo

Paolo Bonzini (5):
  scsi-bus: prepare scsi_req_new for introduction of parse_cdb
  scsi-bus: introduce parse_cdb in SCSIDeviceClass and SCSIBusInfo
  scsi-block: extract scsi_block_is_passthrough
  scsi-block, scsi-generic: implement parse_cdb
  virtio-scsi: implement parse_cdb

 hw/scsi/scsi-bus.c     | 68 ++++++++++++++++++++++++++++++++++----------------
 hw/scsi/scsi-disk.c    | 52 +++++++++++++++++++++++++++++---------
 hw/scsi/scsi-generic.c |  7 ++++++
 hw/scsi/virtio-scsi.c  | 24 ++++++++++++++++++
 include/hw/scsi/scsi.h |  7 ++++++
 5 files changed, 124 insertions(+), 34 deletions(-)

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1.9.3