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 8-11 support vq reset and vq restart for vhost-kernel.
3. Patches 12-14 support vq reset and vq restart for virtio-net.
5. Patch 15 enables the vq reset feature for vhost-kernel.
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_virtqueue_stop()
-> __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]
-> vhost_net_set_backend()
-> set enabled, reset status of vq.
Test environment and method:
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)
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-xuanz...@linux.alibaba.com/
Host Kernel Patch:
https://lore.kernel.org/bpf/20220825085610.80315-1-kangjie...@linux.alibaba.com/
Looking forward to your review and comments. Thanks.
changelog:
v4:
1. Add explanation for preventing userspace datapath in virtio-net.
2. Return error when vhost is not started in vhost_net_virtqueue_restart().
3. Reset the virtqueue in the device reusing vhost_virtqueue_stop().
4. Disable queue reset feature for pre-7.2 machine.
v3:
1. Remove support for vhost-user in this series and refactor the code.
2. Rename 'vhost_net_virtqueue_stop' to 'vhost_net_virtqueue_reset'.
3. Make PCI transport ready before device ready when queue_enabled is set to
true.
4. Add some comments.
v2:
1. Add support for vhost-net kernel scenario.
2. Add a new vhost-user message VHOST_USER_RESET_VRING.
3. Add migration compatibility for virtqueue reset.
Kangjie Xu (10):
virtio: introduce virtio_queue_enable()
virtio: core: vq reset feature negotation support
virtio-pci: support queue enable
vhost: expose vhost_virtqueue_start()
vhost: expose vhost_virtqueue_stop()
vhost-net: vhost-kernel: introduce vhost_net_virtqueue_reset()
vhost-net: vhost-kernel: introduce vhost_net_virtqueue_restart()
virtio-net: introduce flush_or_purge_queued_packets()
virtio-net: support queue_enable
vhost: vhost-kernel: 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
hw/core/machine.c | 4 +-
hw/net/vhost_net.c | 78 +++++++++++++++++++
hw/net/virtio-net.c | 56 +++++++++++--
hw/virtio/vhost.c | 16 ++--
hw/virtio/virtio-pci.c | 16 ++++
hw/virtio/virtio.c | 62 +++++++++++----
include/hw/virtio/vhost.h | 5 ++
include/hw/virtio/virtio-pci.h | 5 ++
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 +
12 files changed, 229 insertions(+), 32 deletions(-)
--
2.32.0
