On Tue, 8 Feb 2022 10:58:45 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
> 2022/2/7 pm 3:19, Xuan Zhuo :
> > On Mon, 7 Feb 2022 14:45:02 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> >> 2022/1/26 pm 3:35, Xuan Zhuo :
> >>> Performing reset on a queue is divided into two steps:
> >>>
> >>> 1. reset_vq: reset one vq
> >>> 2. enable_reset_vq: re-enable the reset queue
> >>>
> >>> In the first step, these tasks will be completed:
> >>> 1. notify the hardware queue to reset
> >>> 2. recycle the buffer from vq
> >>> 3. release the ring of the vq
> >>>
> >>> The second step is similar to find vqs,
> >>
> >> Not sure, since find_vqs will usually try to allocate interrupts.
> >>
> >>
> > Yes.
> >
> >
> >>> passing parameters callback and
> >>> name, etc. Based on the original vq, the ring is re-allocated and
> >>> configured to the backend.
> >>
> >> I wonder whether we really have such requirement.
> >>
> >> For example, do we really have a use case that may change:
> >>
> >> vq callback, ctx, ring_num or even re-create the virtqueue?
> > 1. virtqueue is not recreated
> > 2. ring_num can be used to modify ring num by ethtool -G
>
>
> It looks to me we don't support this right now.
I am trying to implement this function based on virtio queue reset. It will be
added to the next version.
>
>
> >
> > There is really no scene to modify vq callback, ctx, name.
> >
> > Do you mean we still use the old one instead of adding these parameters?
>
>
> Yes, I think for driver we need to implement the function that is needed
> for the first user (e.g AF_XDP). If there's no use case, we can leave
> those extension for the future.
OK.
Thanks.
>
> Thanks
>
>
> >
> > Thanks.
> >
> >> Thanks
> >>
> >>
> >>> So add two callbacks reset_vq, enable_reset_vq to struct
> >>> virtio_config_ops.
> >>>
> >>> Add a structure for passing parameters. This will facilitate subsequent
> >>> expansion of the parameters of enable reset vq.
> >>> There is currently only one default extended parameter ring_num.
> >>>
> >>> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> >>> ---
> >>> include/linux/virtio_config.h | 43 ++++++++++++++++++++++++++++++++++-
> >>> 1 file changed, 42 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> >>> index 4d107ad31149..51dd8461d1b6 100644
> >>> --- a/include/linux/virtio_config.h
> >>> +++ b/include/linux/virtio_config.h
> >>> @@ -16,6 +16,44 @@ struct virtio_shm_region {
> >>> u64 len;
> >>> };
> >>>
> >>> +typedef void vq_callback_t(struct virtqueue *);
> >>> +
> >>> +/* virtio_reset_vq: specify parameters for queue_reset
> >>> + *
> >>> + * vdev: the device
> >>> + * queue_index: the queue index
> >>> + *
> >>> + * free_unused_cb: callback to free unused bufs
> >>> + * data: used by free_unused_cb
> >>> + *
> >>> + * callback: callback for the virtqueue, NULL for vq that do not need a
> >>> + * callback
> >>> + * name: virtqueue names (mainly for debugging), NULL for vq unused by
> >>> + * driver
> >>> + * ctx: ctx
> >>> + *
> >>> + * ring_num: specify ring num for the vq to be re-enabled. 0 means use the
> >>> + * default value. MUST be a power of 2.
> >>> + */
> >>> +struct virtio_reset_vq;
> >>> +typedef void vq_reset_callback_t(struct virtio_reset_vq *param, void *buf);
> >>> +struct virtio_reset_vq {
> >>> + struct virtio_device *vdev;
> >>> + u16 queue_index;
> >>> +
> >>> + /* reset vq param */
> >>> + vq_reset_callback_t *free_unused_cb;
> >>> + void *data;
> >>> +
> >>> + /* enable reset vq param */
> >>> + vq_callback_t *callback;
> >>> + const char *name;
> >>> + const bool *ctx;
> >>> +
> >>> + /* ext enable reset vq param */
> >>> + u16 ring_num;
> >>> +};
> >>> +
> >>> /**
> >>> * virtio_config_ops - operations for configuring a virtio device
> >>> * Note: Do not assume that a transport implements all of the operations
> >>> @@ -74,8 +112,9 @@ struct virtio_shm_region {
> >>> * @set_vq_affinity: set the affinity for a virtqueue (optional).
> >>> * @get_vq_affinity: get the affinity for a virtqueue (optional).
> >>> * @get_shm_region: get a shared memory region based on the index.
> >>> + * @reset_vq: reset a queue individually
> >>> + * @enable_reset_vq: enable a reset queue
> >>> */
> >>> -typedef void vq_callback_t(struct virtqueue *);
> >>> struct virtio_config_ops {
> >>> void (*enable_cbs)(struct virtio_device *vdev);
> >>> void (*get)(struct virtio_device *vdev, unsigned offset,
> >>> @@ -100,6 +139,8 @@ struct virtio_config_ops {
> >>> int index);
> >>> bool (*get_shm_region)(struct virtio_device *vdev,
> >>> struct virtio_shm_region *region, u8 id);
> >>> + int (*reset_vq)(struct virtio_reset_vq *param);
> >>> + struct virtqueue *(*enable_reset_vq)(struct virtio_reset_vq *param);
> >>> };
> >>>
> >>> /* If driver didn't advertise the feature, it will never appear. */
>
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