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

[Paolo Bonzini]

Il 06/08/2014 07:34, Fam Zheng ha scritto:
> 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
> 

I'm applying the patches to scsi-next.  However, please resubmit the
last two with the review comments addressed.  I'm only pushing them so
that we don't both spend time rebasing the branch.

Thanks,

Paolo

Thanks