[RFC PATCH V2 0/8] Packed ring for vhost

[Jason Wang]

Hi all:

This RFC implement packed ring layout. The code were tested with pmd
implement by Jens at
http://dpdk.org/ml/archives/dev/2018-January/089417.html. Minor change
was needed for pmd codes to kick virtqueue since it assumes a busy
polling backend.

Test were done between localhost and guest. Testpmd (rxonly) in guest
reports 2.4Mpps. Testpmd (txonly) repots about 2.1Mpps.

Notes: The event suppression /indirect descriptor support is complied
       test only because of lacked driver support.

Changes from V1:

- Refactor vhost used elem code to avoid open coding on used elem
- Event suppression support (compile test only).
- Indirect descriptor support (compile test only).
- Zerocopy support.
- vIOMMU support.
- SCSI/VSOCK support (compile test only).
- Fix several bugs

For simplicity, I don't implement batching or other optimizations.

Please review.

Thanks

Jason Wang (8):
  vhost: move get_rx_bufs to vhost.c
  vhost: hide used ring layout from device
  vhost: do not use vring_used_elem
  vhost_net: do not explicitly manipulate vhost_used_elem
  vhost: vhost_put_user() can accept metadata type
  virtio: introduce packed ring defines
  vhost: packed ring support
  vhost: event suppression for packed ring

 drivers/vhost/net.c                | 138 ++-----
 drivers/vhost/scsi.c               |  62 +--
 drivers/vhost/vhost.c              | 818 ++++++++++++++++++++++++++++++++++---
 drivers/vhost/vhost.h              |  46 ++-
 drivers/vhost/vsock.c              |  42 +-
 include/uapi/linux/virtio_config.h |   9 +
 include/uapi/linux/virtio_ring.h   |  32 ++
 7 files changed, 921 insertions(+), 226 deletions(-)

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2.7.4