[RFC,0/2] Vhost-vdpa Shadow Virtqueue Hash calculation Support

Message

Hawkins Jiawei Aug. 11, 2023, 2:50 p.m. UTC

This series enables shadowed CVQ to intercept
VIRTIO_NET_CTRL_MQ_HASH_CONFIG command through shadowed CVQ,
update the virtio NIC device model so qemu send it in a
migration, and the restore of that Hash calculation state
in the destination.

Note that this patch should be based on
patch "vdpa: Send all CVQ state load commands in parallel" at [1].

[1]. https://lore.kernel.org/all/[e-mail]/

TestStep
========
1. test the migration using vp-vdpa device
  - For L0 guest, boot QEMU with two virtio-net-pci net device with
`ctrl_vq`, `mq`, `hash` features on, command line like:
	-netdev tap,...
	-device virtio-net-pci,disable-legacy=on,disable-modern=off,
iommu_platform=on,mq=on,ctrl_vq=on,hash=on,guest_announce=off,
indirect_desc=off,queue_reset=off,...

  - For L1 guest, apply the relative patch series and compile the
source code, start QEMU with two vdpa device with svq mode on,
enable the `ctrl_vq`, `mq`, `hash` features on, command line like:
      -netdev type=vhost-vdpa,x-svq=true,...
      -device virtio-net-pci,mq=on,guest_announce=off,ctrl_vq=on,
hash=on,...

  - For L2 source guest, run the following bash command:
```bash
#!/bin/sh

ethtool -K eth0 rxhash on
```
  - Gdb attach the destination VM and break at the
vhost_vdpa_net_load_rss()

  - Execute the live migration in L2 source monitor

  - Result
    * with this series, gdb can hit the breakpoint and continue
the executing without triggering any error or warning.

Hawkins Jiawei (2):
  vdpa: Restore hash calculation state
  vdpa: Allow VIRTIO_NET_F_HASH_REPORT in SVQ

 net/vhost-vdpa.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)