[Qemu-devel] [RFC PATCH v2 00/10] virtio-scsi: Dataplane on single iothread

[Fam Zheng <famz@redhat.com>]

Hi all,

This series adds "iothread" property to virtio-scsi in a way just similar to
virtio-blk, and turns all scsi devices to run on top of it.

Example:

    -object iothread,id=iothread-1  \
    -device virtio-scsi-pci,id=virtio-scsi-bus-0,iothread=iothread-1  \
    -drive file=guest.img,id=scsi-disk-1,if=none,cache=none,aio=native  \
    -device scsi-disk,lun=1,drive=scsi-disk-1,id=scsi-disk-1

It uses irqfd, ioeventfd and vring in a way just like virtio-blk does now.

Please review the general approach and see if major points are missed in terms
of thread safety and completeness of the moved things from original context to
iothread context.

Note that the used vring is not function complete compared to virtqueue
implementation, because of its lacking of MMIO handling. So this is just an
RFC.

Migration hasn't been looked into yet, either.  Assigning multiple iothreads is
supposed to be worked on top of this as well, but it's not thoroughly planned
yet.

Thanks,
Fam


Fam Zheng (10):
  virtio: Compile vring code unconditionally
  virtio-scsi: Split virtio_scsi_handle_cmd_req from
    virtio_scsi_handle_cmd
  virtio-scsi: Split virtio_scsi_handle_ctrl_req from
    virtio_scsi_handle_ctrl
  virtio-scsi: Add VirtIOSCSIVring in VirtIOSCSIReq
  virtio-scsi: Make virtio_scsi_init_req public
  virtio-scsi: Make virtio_scsi_free_req public
  virtio-scsi: Make virtio_scsi_push_event public
  virtio-scsi: Add 'iothread' property to virtio-scsi-pci
  virtio-scsi-dataplane: Code to run virtio-scsi on iothread
  virtio-scsi: Hook up with dataplane

 hw/scsi/Makefile.objs           |   2 +-
 hw/scsi/virtio-scsi-dataplane.c | 219 +++++++++++++++++++++++++++++++++
 hw/scsi/virtio-scsi.c           | 260 +++++++++++++++++++++++++---------------
 hw/virtio/Makefile.objs         |   2 +-
 hw/virtio/virtio-pci.c          |   2 +
 include/hw/virtio/virtio-scsi.h |  65 ++++++++++
 6 files changed, 450 insertions(+), 100 deletions(-)
 create mode 100644 hw/scsi/virtio-scsi-dataplane.c

-- 
2.0.3