[PATCH 0/8] Support VIRTIO_F_RING_RESET for vhost-user in virtio pci-modern

[Kangjie Xu]

This patch set is based on the patch set that supports VIRTIO_F_RING_RESET for 
vhost-kernel:
    
cover.1661414345.git.kangjie.xu@linux.alibaba.com/T/">https://lore.kernel.org/qemu-devel/cover.1661414345.git.kangjie.xu@linux.alibaba.com/T/

The virtio queue reset function has already been defined in the virtio spec 1.2.
The relevant virtio spec information is here:

    https://github.com/oasis-tcs/virtio-spec/issues/124
    https://github.com/oasis-tcs/virtio-spec/issues/139

This patch set is to support this function for vhost-user in QEMU. It consists 
of several parts:
Patch 1: docs about vhost-user message VHOST_USER_RESET_VRING.
Patch 2: rename vhost_set_vring_enable to vhost_set_dev_enable.
Patches 3-4: support in vhost-user module.
Patches 5-6: support in vhost-net module.
Patch 7: support in virtio-net module.
Patch 8: add feature negotitation support.

The process of virtqueue reset can be concluded as:
1. The virtqueue is disabled when VIRTIO_PCI_COMMON_Q_RESET is written.
2. Then the virtqueue can be optionally restarted(re-enabled).

The detailed process is listed below:
1. VIRTIO_PCI_COMMON_Q_RESET is written [virtio-pci]
    -> virtio_queue_reset() [virtio]
        -> virtio_net_queue_reset() [virtio-net]
            -> vhost_net_virtqueue_reset() [vhost-net]
                -> vhost_user_reset_vring() [vhost-user]
                    -> send VHOST_USER_RESET_VRING to the device
                -> vhost_virtqueue_unmap()
        -> __virtio_queue_reset()
2. VIRTIO_PCI_COMMON_Q_ENABLE is written [virtio-pci]
    -> virtio_queue_enable() [virtio]
        -> virtio_net_queue_enable() [virtio-net]
            -> vhost_net_virtqueue_restart() [vhost-net]
                -> vhost_virtqueue_start()
                -> vhost_user_set_vring_enable [vhost-user]
                    -> send VHOST_USER_SET_VRING_ENABLE to the device
    -> set enabled, reset status of vq.

Test environment:
    Qemu: QEMU emulator version 7.0.50
    Guest: 5.19.0-rc3 (With vq reset support)
    DPDK: 22.07-rc1 (With vq reset support)
    Test Cmd: ethtool -g eth1; ethtool -G eth1 rx $1 tx $2; ethtool -g eth1;

    The drvier can resize the virtio queue, then virtio queue reset function 
should
    be triggered.

    The default is split mode, modify Qemu virtio-net to add PACKED feature to 
    test packed mode.

Guest Kernel Patch:
    
https://lore.kernel.org/bpf/20220801063902.129329-1-xuanzhuo@linux.alibaba.com/

DPDK Patch:
    
https://github.com/middaywords/dpdk/compare/72206323a5dd3182b13f61b25a64abdddfee595c...eabadfac7953da66bc10ffb8284b490d09bb7ec7

changelog:(based the series 
https://lore.kernel.org/qemu-devel/cover.1658141552.git.kangjie.xu@linux.alibaba.com/T/#t)
1. rename vhost_set_vring_enable to vhost_set_dev_enable.
2. add vhost-user message VHOST_USER_RESET_VRING
3. remove restart/reset functions of virtqueue in vhost module.

Kangjie Xu (8):
  docs: vhost-user: add VHOST_USER_RESET_VRING message
  net: virtio: rename vhost_set_vring_enable to vhost_set_dev_enable
  vhost-user: add op to enable or disable a single vring
  vhost-user: introduce vhost_reset_vring() interface
  vhost-net: vhost-user: update vhost_net_virtqueue_reset()
  vhost-net: vhost-user: update vhost_net_virtqueue_restart()
  virtio-net: vhost-user: update queue_reset and queue_enable
  vhost: vhost-user: enable vq reset feature

 backends/cryptodev-vhost.c        | 12 +++---
 docs/interop/vhost-user.rst       | 10 +++++
 hw/net/vhost_net-stub.c           |  2 +-
 hw/net/vhost_net.c                | 34 +++++++++++++---
 hw/net/virtio-net.c               | 10 +++--
 hw/virtio/vhost-user.c            | 68 +++++++++++++++++++++++++++----
 include/hw/virtio/vhost-backend.h |  8 +++-
 include/net/vhost_net.h           |  2 +-
 8 files changed, 119 insertions(+), 27 deletions(-)

-- 
2.32.0