[RFC PATCH v2 0/3] Vhost-vdpa Shadow Virtqueue RSS Support

[Hawkins Jiawei <yin31149@gmail.com>]

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

Note that this patch should be based on
patch "Vhost-vdpa Shadow Virtqueue Hash calculation Support" at [1].

[1]. https://lore.kernel.org/all/cover.1691762906.git.yin31149@gmail.com/

ChangeLog
=========
v2:
  - Correct the feature usage to VIRTIO_NET_F_HASH_REPORT when
loading the hash calculation state in
patch "vdpa: Restore receive-side scaling state"

v1: https://lore.kernel.org/all/cover.1691766252.git.yin31149@gmail.com/

TestStep
========
1. test the migration using vp-vdpa device
  - For L0 guest, boot QEMU with two virtio-net-pci net device with
`in-qemu` RSS, command line like:
	-netdev tap,vhost=off...
	-device virtio-net-pci,disable-legacy=on,disable-modern=off,
iommu_platform=on,mq=on,ctrl_vq=on,hash=on,rss=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`, `rss` features on, command line like:
      -netdev type=vhost-vdpa,x-svq=true,...
      -device virtio-net-pci,mq=on,guest_announce=off,ctrl_vq=on,
rss=on,...

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

ethtool -K eth0 rxhash on
```

  - Execute the live migration in L2 source monitor

  - Result
    * with this series, L2 QEMU can execute without
triggering any error or warning. L0 QEMU echo
"Can't load eBPF RSS - fallback to software RSS".

Hawkins Jiawei (3):
  vdpa: Add SetSteeringEBPF method for NetClientState
  vdpa: Restore receive-side scaling state
  vdpa: Allow VIRTIO_NET_F_RSS in SVQ

 net/vhost-vdpa.c | 63 ++++++++++++++++++++++++++++++++++--------------
 1 file changed, 45 insertions(+), 18 deletions(-)

-- 
2.25.1