Re: [PATCH v4 00/14] virtio pci support VIRTIO_F_RING_RESET

[Jason Wang <jasowang@redhat.com>]

On Wed, Feb 9, 2022 at 8:29 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
>
> 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.

So I had an idea, we can implement ethtool_set_ringparam() in this
series to get one real users.

But this came into another question: it looks to me current virito-net
just uses the maximum ring size, so it basically means we just can
decrease the number from startup, so I wonder how much value if we
don't limit the startup queue size to a dedicated value.

Thanks

>
> Please review. Thanks.
>
> 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 (14):
>   virtio_pci: struct virtio_pci_common_cfg add queue_notify_data
>   virtio: queue_reset: add VIRTIO_F_RING_RESET
>   virtio_ring: queue_reset: add function vring_setup_virtqueue()
>   virtio_ring: queue_reset: split: add __vring_init_virtqueue()
>   virtio_ring: queue_reset: split: support enable reset queue
>   virtio_ring: queue_reset: packed: support enable reset queue
>   virtio_ring: queue_reset: extract the release function of the vq ring
>   virtio_ring: queue_reset: add vring_release_virtqueue()
>   virtio: queue_reset: struct virtio_config_ops add callbacks for
>     queue_reset
>   virtio_pci: queue_reset: update struct virtio_pci_common_cfg and
>     option functions
>   virtio_pci: queue_reset: release vq by vp_dev->vqs
>   virtio_pci: queue_reset: setup_vq() support vring_setup_virtqueue()
>   virtio_pci: queue_reset: vp_setup_vq() support ring_num
>   virtio_pci: queue_reset: support VIRTIO_F_RING_RESET
>
>  drivers/virtio/virtio_pci_common.c     |  65 +++++++---
>  drivers/virtio/virtio_pci_common.h     |  11 +-
>  drivers/virtio/virtio_pci_legacy.c     |   5 +-
>  drivers/virtio/virtio_pci_modern.c     |  99 ++++++++++++--
>  drivers/virtio/virtio_pci_modern_dev.c |  36 +++++
>  drivers/virtio/virtio_ring.c           | 173 ++++++++++++++++++-------
>  include/linux/virtio.h                 |   6 +
>  include/linux/virtio_config.h          |  13 ++
>  include/linux/virtio_pci_modern.h      |   2 +
>  include/linux/virtio_ring.h            |  37 ++++--
>  include/uapi/linux/virtio_config.h     |   7 +-
>  include/uapi/linux/virtio_pci.h        |  14 ++
>  12 files changed, 375 insertions(+), 93 deletions(-)
>
> --
> 2.31.0
>