[PATCH 00/24] Support VIRTIO_F_RING_RESET for virtio-net, vhost-user, vhost-kernel in virtio pci-modern

[Kangjie Xu <kangjie.xu@linux.alibaba.com>]

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 in QEMU. It consists of several parts:
1. Patches 1-7 are the basic interfaces for vq reset in virtio and virtio-pci.
2. Patches 8-12 support vq stop and vq restart for vhost-kernel.
3. Patches 13-19 support vq stop and vq restart for vhost-user.
4. Patches 20-22 support vq reset and re-enable for virtio-net.
5. Patches 23-24 enable the vq reset feature for vhost-kernel and vhost-user.

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).

Since this patch set involves multiple modules and seems a bit messy, we briefly describe the
calling process for different modes below.
virtio-net:
1. VIRTIO_PCI_COMMON_Q_RESET is written [virtio-pci]
    -> virtio_queue_reset() [virtio]
        -> virtio_net_queue_reset() [virtio-net]
        -> __virtio_queue_reset()
2. VIRTIO_PCI_COMMON_Q_ENABLE is written [virtio-pci]
    -> set enabled, reset status of vq.

vhost-kernel:
1. VIRTIO_PCI_COMMON_Q_RESET is written [virtio-pci]
    -> virtio_queue_reset() [virtio]
        -> virtio_net_queue_reset() [virtio-net]
            -> vhost_net_virtqueue_stop() [vhost-net]
                -> vhost_net_set_backend() [vhost]
                -> vhost_dev_virtqueue_stop()
                    -> 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_dev_virtqueue_restart() [vhost]
                    -> vhost_virtqueue_start()
                -> vhost_net_set_backend()
    -> set enabled, reset status of vq.

vhost-user:
1. VIRTIO_PCI_COMMON_Q_RESET is written [virtio-pci]
    -> virtio_queue_reset() [virtio]
        -> virtio_net_queue_reset() [virtio-net]
            -> vhost_net_virtqueue_stop() [vhost-net]
                -> vhost_dev_virtqueue_stop() [vhost]
                    -> 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_dev_virtqueue_restart() [vhost]
                    -> vhost_virtqueue_start()
                    -> vhost_user_set_single_vring_enable [vhost-user]
                        -> send VHOST_USER_SET_VRING_ENABLE to the device
    -> set enabled, reset status of vq.


Test environment:
    Host: 5.19.0-rc3 (With vq reset support)
    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

Host Kernel Patch:
    https://github.com/middaywords/linux/commit/19a91e0d7167b2031e46078c6215c213b89cb2c3

Looking forward to your review and comments. Thanks.

Kangjie Xu (19):
  virtio: introduce virtio_queue_enable()
  virtio: core: vq reset feature negotation support
  virtio-pci: support queue enable
  vhost: extract the logic of unmapping the vrings and desc
  vhost: introduce vhost_dev_virtqueue_stop()
  vhost: introduce vhost_dev_virtqueue_restart()
  vhost-net: vhost-kernel: introduce vhost_net_virtqueue_stop()
  vhost-net: vhost-kernel: introduce vhost_net_virtqueue_restart()
  docs: vhost-user: add VHOST_USER_RESET_VRING message
  vhost-user: introduce vhost_reset_vring() interface
  vhost-user: add op to enable or disable a single vring
  vhost: vhost-user: update vhost_dev_virtqueue_stop()
  vhost: vhost-user: update vhost_dev_virtqueue_restart()
  vhost-net: vhost-user: update vhost_net_virtqueue_stop()
  vhost-net: vhost-user: update vhost_net_virtqueue_restart()
  virtio-net: introduce flush_or_purge_queued_packets()
  virtio-net: support queue_enable
  vhost: vhost-kernel: enable vq reset feature
  vhost: vhost-user: enable vq reset feature

Xuan Zhuo (5):
  virtio: sync relevant definitions with linux
  virtio: introduce __virtio_queue_reset()
  virtio: introduce virtio_queue_reset()
  virtio-pci: support queue reset
  virtio-net: support queue reset

 docs/interop/vhost-user.rst                   | 10 +++
 hw/core/machine.c                             |  1 +
 hw/net/vhost_net.c                            | 79 +++++++++++++++++++
 hw/net/virtio-net.c                           | 58 ++++++++++++--
 hw/virtio/vhost-user.c                        | 67 ++++++++++++++--
 hw/virtio/vhost.c                             | 79 +++++++++++++++++--
 hw/virtio/virtio-pci.c                        | 20 +++++
 hw/virtio/virtio.c                            | 62 +++++++++++----
 include/hw/virtio/vhost-backend.h             |  6 ++
 include/hw/virtio/vhost.h                     |  5 ++
 include/hw/virtio/virtio-pci.h                |  1 +
 include/hw/virtio/virtio.h                    |  8 +-
 include/net/vhost_net.h                       |  4 +
 .../standard-headers/linux/virtio_config.h    |  5 ++
 include/standard-headers/linux/virtio_pci.h   |  2 +
 15 files changed, 371 insertions(+), 36 deletions(-)

-- 
2.32.0