[dpdk-dev] [PATCH 0/4 for 2.3] vhost-user live migration support

[Yuanhan Liu]

This patch set adds the initial vhost-user live migration support.

The major task behind that is to log pages we touched during
live migration. So, this patch is basically about adding vhost
log support, and using it.

Patchset
========
- Patch 1 handles VHOST_USER_SET_LOG_BASE, which tells us where
  the dirty memory bitmap is.
    
- Patch 2 introduces a vhost_log_write() helper function to log
  pages we are gonna change.

- Patch 3 logs changes we made to used vring.

- Patch 4 sets log_fhmfd protocol feature bit, which actually
  enables the vhost-user live migration support.

A simple test guide (on same host)
==================================

The following test is based on OVS + DPDK. And here is guide
to setup OVS + DPDK:

    http://wiki.qemu.org/Features/vhost-user-ovs-dpdk

1. start ovs-vswitchd

2. Add two ovs vhost-user port, say vhost0 and vhost1

3. Start a VM1 to connect to vhost0. Here is my example:

   $QEMU -enable-kvm -m 1024 -smp 4 \
       -chardev socket,id=char0,path=/var/run/openvswitch/vhost0  \
       -netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \
       -device virtio-net-pci,netdev=mynet1,mac=52:54:00:12:34:58 \
       -object memory-backend-file,id=mem,size=1024M,mem-path=$HOME/hugetlbfs,share=on \
       -numa node,memdev=mem -mem-prealloc \
       -kernel $HOME/iso/vmlinuz -append "root=/dev/sda1" \
       -hda fc-19-i386.img \
       -monitor telnet::3333,server,nowait -curses

4. run "ping $host" inside VM1

5. Start VM2 to connect to vhost0, and marking it as the target
   of live migration (by adding -incoming tcp:0:4444 option)

   $QEMU -enable-kvm -m 1024 -smp 4 \
       -chardev socket,id=char0,path=/var/run/openvswitch/vhost1  \
       -netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \
       -device virtio-net-pci,netdev=mynet1,mac=52:54:00:12:34:58 \
       -object memory-backend-file,id=mem,size=1024M,mem-path=$HOME/hugetlbfs,share=on \
       -numa node,memdev=mem -mem-prealloc \
       -kernel $HOME/iso/vmlinuz -append "root=/dev/sda1" \
       -hda fc-19-i386.img \
       -monitor telnet::3334,server,nowait -curses \
       -incoming tcp:0:4444 

6. connect to VM1 monitor, and start migration:

   > migrate tcp:0:4444

7. After a while, you will find that VM1 has been migrated to VM2,
   and the "ping" command continues running, perfectly.


Note: this patch set has mostly been based on Victor Kaplansk's demo
work (vhost-user-bridge) at QEMU project. I was thinking to add Victor
as the co-author. Victor, what do you think of that? :)

Comments are welcome!

---
Yuanhan Liu (4):
  vhost: handle VHOST_USER_SET_LOG_BASE request
  vhost: introduce vhost_log_write
  vhost: log vring changes
  vhost: enable log_shmfd protocol feature

 lib/librte_vhost/rte_virtio_net.h             | 35 ++++++++++++++
 lib/librte_vhost/vhost_rxtx.c                 | 70 ++++++++++++++++++---------
 lib/librte_vhost/vhost_user/vhost-net-user.c  |  7 ++-
 lib/librte_vhost/vhost_user/vhost-net-user.h  |  6 +++
 lib/librte_vhost/vhost_user/virtio-net-user.c | 44 +++++++++++++++++
 lib/librte_vhost/vhost_user/virtio-net-user.h |  5 +-
 lib/librte_vhost/virtio-net.c                 |  4 ++
 7 files changed, 145 insertions(+), 26 deletions(-)

-- 
1.9.0