Re: [PATCH v8 00/16] virtio pci support VIRTIO_F_RING_RESET (refactor vring)

[Jason Wang <jasowang@redhat.com>]

在 2022/3/14 下午5:34, Xuan Zhuo 写道:
> The virtio spec already supports the virtio queue reset function. This patch set
> is to add this function to the kernel. The relevant virtio spec information is
> here:
>
>      https://github.com/oasis-tcs/virtio-spec/issues/124
>
> Also regarding MMIO support for queue reset, I plan to support it after this
> patch is passed.
>
> This patch set implements the refactoring of vring. Finally, the
> virtuque_resize() interface is provided based on the reset function of the
> transport layer.
>
> Test environment:
>      Host: 4.19.91
>      Qemu: QEMU emulator version 6.2.50 (with vq reset support)


It would be better if you can post Qemu code for review as well.


>      Test Cmd:  ethtool -G eth1 rx $1 tx $2; ethtool -g eth1
>
>      The default is split mode, modify Qemu virtio-net to add PACKED feature to test
>      packed mode.
>
> Please review. Thanks.


Looks good overall, see comments in individual patch.

I think the code is structured in a way that is not friendly to the 
reviewers. For next version, we can bring back the ethtool -G for 
virtio-net.

Thanks


>
> v8:
>    1. Provide a virtqueue_reset() interface directly
>    2. Split the two patch sets, this is the first part
>    3. Add independent allocation helper for allocating state, extra
>
> v7:
>    1. fix #6 subject typo
>    2. fix #6 ring_size_in_bytes is uninitialized
>    3. check by: make W=12
>
> v6:
>    1. virtio_pci: use synchronize_irq(irq) to sync the irq callbacks
>    2. Introduce virtqueue_reset_vring() to implement the reset of vring during
>       the reset process. May use the old vring if num of the vq not change.
>    3. find_vqs() support sizes to special the max size of each vq
>
> v5:
>    1. add virtio-net support set_ringparam
>
> v4:
>    1. just the code of virtio, without virtio-net
>    2. Performing reset on a queue is divided into these steps:
>      1. reset_vq: reset one vq
>      2. recycle the buffer from vq by virtqueue_detach_unused_buf()
>      3. release the ring of the vq by vring_release_virtqueue()
>      4. enable_reset_vq: re-enable the reset queue
>    3. Simplify the parameters of enable_reset_vq()
>    4. add container structures for virtio_pci_common_cfg
>
> v3:
>    1. keep vq, irq unreleased
>
> Xuan Zhuo (16):
>    virtio: add helper virtqueue_get_vring_max_size()
>    virtio: struct virtio_config_ops add callbacks for queue_reset
>    virtio_ring: update the document of the virtqueue_detach_unused_buf
>      for queue reset
>    virtio_ring: remove the arg vq of vring_alloc_desc_extra()
>    virtio_ring: extract the logic of freeing vring
>    virtio_ring: split: extract the logic of alloc queue
>    virtio_ring: split: extract the logic of alloc state and extra
>    virtio_ring: split: extract the logic of attach vring
>    virtio_ring: split: extract the logic of vq init
>    virtio_ring: split: implement virtqueue_resize_split()
>    virtio_ring: packed: extract the logic of alloc queue
>    virtio_ring: packed: extract the logic of alloc state and extra
>    virtio_ring: packed: extract the logic of attach vring
>    virtio_ring: packed: extract the logic of vq init
>    virtio_ring: packed: implement virtqueue_resize_packed()
>    virtio_ring: introduce virtqueue_resize()
>
>   drivers/virtio/virtio_mmio.c       |   2 +
>   drivers/virtio/virtio_pci_legacy.c |   2 +
>   drivers/virtio/virtio_pci_modern.c |   2 +
>   drivers/virtio/virtio_ring.c       | 604 ++++++++++++++++++++++-------
>   include/linux/virtio.h             |   5 +
>   include/linux/virtio_config.h      |  12 +
>   6 files changed, 494 insertions(+), 133 deletions(-)
>
> --
> 2.31.0
>

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