[dpdk-dev] [PATCH v9 0/6] virtio support for container

Jianfeng Tan jianfeng.tan at intel.com
Wed Jun 15 11:03:19 CEST 2016

 - Squash a patch in mq support of virtio-user to use virtual address
   in control queue inside this series.
 - A regression bug fix, missed "%s" when printing some message.
 - Run check-git-log.sh, change pci to PCI.

 - Change to use max_queue_pairs instead of queue_pairs to initialize
   and deinitialize queues.
 - Remove vhost-kernel support.

 - uint64_t -> uintptr_t, so that it can be compiled on 32-bit platform.
 - Rebase on latest dpdk-next-virtio branch.
 - Abandon abstracting related code into vring_hdr_desc_init(), instead,
   just move it behind setup_queue().

 - Move driver related code into from driver/net/virtio/virtio-user/ to
   driver/net/virtio/ directory, inside virtio_user_ethdev.c.
 - Rename vdev to virtio_user in comments and code.
 - Merge code, which lies in virtio_user_pci.c, into virtio_user_ethdev.c.
 - Add some comments at virtio-user special handling at virtio_dev_ethdev.c.
 - Merge document update into the 7nd commit where virtio-user is added.
 - Add usage with vhost-switch in vhost.rst.

 - Rename struct virtio_user_hw to struct virtio_user_dev.
 - Rename "vdev_private" to "virtio_user_dev".
 - Move special handling into virtio_ethdev.c from queue_setup().
 - Add vring in virtio_user_dev (remove rte_eth_dev_data), so that
   device does not depend on driver's data structure (rte_eth_dev_data).
 - Remove update on doc/guides/nics/overview.rst, because virtio-user has
   exact feature set with virtio.
 - Change "unsigned long int" to "uint64_t", "unsigned" to "uint32_t".
 - Remove unnecessary cast in vdev_read_dev_config().
 - Add functions in virtio_user_dev.c with prefix of "virtio_user_".
 - Rebase on virtio-next-virtio.

 - Avoid using dev_type, instead use (eth_dev->pci_device is NULL) to
   judge if it's virtual device or physical device.
 - Change the added device name to virtio-user.
 - Split into vhost_user.c, vhost_kernel.c, vhost.c, virtio_user_pci.c,
 - Move virtio-user specific data from struct virtio_hw into struct
 - Add support to send reset_owner message.
 - Change del_queue implementation. (This need more check)
 - Remove rte_panic(), and superseded with log.
 - Add reset_owner into virtio_pci_ops.reset.
 - Merge parameter "rx" and "tx" to "queues" to emliminate confusion.
 - Move get_features to after set_owner.
 - Redefine path in virtio_user_hw from char * to char [].

 - Remove --single-file option; do no change at EAL memory.
 - Remove the added API rte_eal_get_backfile_info(), instead we check all
   opened files with HUGEFILE_FMT to find hugepage files owned by DPDK.
 - Accordingly, add more restrictions at "Known issue" section.
 - Rename parameter from queue_num to queue_size for confusion.
 - Rename vhost_embedded.c to rte_eth_virtio_vdev.c.
 - Move code related to the newly added vdev to rte_eth_virtio_vdev.c, to
   reuse eth_virtio_dev_init(), remove its static declaration.
 - Implement dev_uninit() for rte_eth_dev_detach().
 - WARN -> ERR, in vhost_embedded.c
 - Add more commit message for clarify the model.

 - Rebase on the patchset of virtio 1.0 support.
 - Fix cannot create non-hugepage memory.
 - Fix wrong size of memory region when "single-file" is used.
 - Fix setting of offset in virtqueue to use virtual address.
 - Fix setting TUNSETVNETHDRSZ in vhost-user's branch.
 - Add mac option to specify the mac address of this virtual device.
 - Update doc.

This patchset is to provide high performance networking interface (virtio)
for container-based DPDK applications. The way of starting DPDK apps in
containers with ownership of NIC devices exclusively is beyond the scope.
The basic idea here is to present a new virtual device (named virtio-user),
which can be discovered and initialized by DPDK. To minimize the change,
we reuse already-existing virtio PMD code (driver/net/virtio/).

Background: Previously, we usually use a virtio device in the context of
QEMU/VM as below pic shows. Virtio nic is emulated in QEMU, and usually
presented in VM as a PCI device.

  |  virtio driver |  ----->  VM
        | ----------> (over PCI bus or MMIO or Channel I/O)
  | device emulate |
  |                |  ----->  QEMU
  | vhost adapter  |
        | ----------> (vhost-user protocol or vhost-net ioctls)
  | vhost backend  |
Compared to QEMU/VM case, virtio support for contaner requires to embedded
device framework inside the virtio PMD. So this converged driver actually
plays three roles:
  - virtio driver to drive this new kind of virtual device;
  - device emulation to present this virtual device and reponse to the
    virtio driver, which is originally by QEMU;
  - and the role to communicate with vhost backend, which is also
    originally by QEMU.

The code layout and functionality of each module:
  | ------------------ |
  | | virtio driver  | |----> (virtio_user_ethdev.c)
  | ------------------ |
  |         |          |
  | ------------------ | ------>  virtio-user PMD
  | | device emulate |-|----> (virtio_user_dev.c)
  | |                | |
  | | vhost adapter  |-|----> (vhost_user.c, vhost_kernel.c, vhost.c)
  | ------------------ |
         | -------------- --> (vhost-user protocol)
   | vhost backend  |

How to share memory? In VM's case, qemu always shares all physical layout
to backend. But it's not feasible for a container, as a process, to share
all virtual memory regions to backend. So only specified virtual memory
regions (with type of shared) are sent to backend. It's a limitation that
only addresses in these areas can be used to transmit or receive packets.

Known issues:
 - Control queue and multi-queue are not supported yet.
 - Cannot work with --huge-unlink.
 - Cannot work with no-huge.
 - Cannot work when there are more than VHOST_MEMORY_MAX_NREGIONS(8)
 - Root privilege is a must (mainly becase of sorting hugepages according
   to physical address).
 - Applications should not use file name like HUGEFILE_FMT ("%smap_%d").
 - Cannot work with vhost kernel.

How to use?

a. Apply this patchset.

b. To compile container apps:
$: make config RTE_SDK=`pwd` T=x86_64-native-linuxapp-gcc
$: make install RTE_SDK=`pwd` T=x86_64-native-linuxapp-gcc
$: make -C examples/l2fwd RTE_SDK=`pwd` T=x86_64-native-linuxapp-gcc
$: make -C examples/vhost RTE_SDK=`pwd` T=x86_64-native-linuxapp-gcc

c. To build a docker image using Dockerfile below.
$: cat ./Dockerfile
FROM ubuntu:latest
WORKDIR /usr/src/dpdk
COPY . /usr/src/dpdk
ENV PATH "$PATH:/usr/src/dpdk/examples/l2fwd/build/"
$: docker build -t dpdk-app-l2fwd .

d. Used with vhost-user
$: ./examples/vhost/build/vhost-switch -c 3 -n 4 \
	--socket-mem 1024,1024 -- -p 0x1 --stats 1
$: docker run -i -t -v <path_to_vhost_unix_socket>:/var/run/usvhost \
	-v /dev/hugepages:/dev/hugepages \
	dpdk-app-l2fwd l2fwd -c 0x4 -n 4 -m 1024 --no-pci \
	--vdev=virtio-user0,path=/var/run/usvhost -- -p 0x1

By the way, it's not necessary to run in a container.

Signed-off-by: Huawei Xie <huawei.xie at intel.com>
Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>
Acked-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>

Jianfeng Tan (6):
  virtio: hide phys addr check inside PCI ops
  virtio: enable use virtual address to fill desc
  virtio-user: add vhost user adapter layer
  virtio-user: add device emulation layer APIs
  virtio-user: add new virtual PCI driver for virtio
  virtio-user: add a new vdev named virtio-user

 config/common_linuxapp                           |   1 +
 doc/guides/rel_notes/release_16_07.rst           |  12 +
 doc/guides/sample_app_ug/vhost.rst               |  17 +
 drivers/net/virtio/Makefile                      |   6 +
 drivers/net/virtio/virtio_ethdev.c               |  83 +++--
 drivers/net/virtio/virtio_ethdev.h               |   2 +
 drivers/net/virtio/virtio_pci.c                  |  30 +-
 drivers/net/virtio/virtio_pci.h                  |   3 +-
 drivers/net/virtio/virtio_rxtx.c                 |   5 +-
 drivers/net/virtio/virtio_rxtx_simple.c          |  13 +-
 drivers/net/virtio/virtio_user/vhost.h           | 141 ++++++++
 drivers/net/virtio/virtio_user/vhost_user.c      | 404 +++++++++++++++++++++
 drivers/net/virtio/virtio_user/virtio_user_dev.c | 227 ++++++++++++
 drivers/net/virtio/virtio_user/virtio_user_dev.h |  62 ++++
 drivers/net/virtio/virtio_user_ethdev.c          | 427 +++++++++++++++++++++++
 drivers/net/virtio/virtqueue.h                   |  10 +
 16 files changed, 1398 insertions(+), 45 deletions(-)
 create mode 100644 drivers/net/virtio/virtio_user/vhost.h
 create mode 100644 drivers/net/virtio/virtio_user/vhost_user.c
 create mode 100644 drivers/net/virtio/virtio_user/virtio_user_dev.c
 create mode 100644 drivers/net/virtio/virtio_user/virtio_user_dev.h
 create mode 100644 drivers/net/virtio/virtio_user_ethdev.c


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