On Mon, Oct 16, 2023 at 8:01 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> If the xsk is enabling, the xsk tx will share the send queue.
> But the xsk requires that the send queue use the premapped mode.
> So the send queue must support premapped mode.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/net/virtio/main.c | 108 ++++++++++++++++++++++++++++----
> drivers/net/virtio/virtio_net.h | 54 +++++++++++++++-
> 2 files changed, 149 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> index 8da84ea9bcbe..02d27101fef1 100644
> --- a/drivers/net/virtio/main.c
> +++ b/drivers/net/virtio/main.c
> @@ -514,20 +514,104 @@ static void *virtnet_rq_alloc(struct virtnet_rq *rq, u32 size, gfp_t gfp)
> return buf;
> }
>
> -static void virtnet_rq_set_premapped(struct virtnet_info *vi)
> +static int virtnet_sq_set_premapped(struct virtnet_sq *sq)
> {
> - int i;
> + struct virtnet_sq_dma *d;
> + int err, size, i;
>
> - /* disable for big mode */
> - if (!vi->mergeable_rx_bufs && vi->big_packets)
> - return;
Not specific to this patch but any plan to fix the big mode?
> + size = virtqueue_get_vring_size(sq->vq);
> +
> + size += MAX_SKB_FRAGS + 2;
> +
> + sq->dmainfo.head = kcalloc(size, sizeof(*sq->dmainfo.head), GFP_KERNEL);
> + if (!sq->dmainfo.head)
> + return -ENOMEM;
> +
> + err = virtqueue_set_dma_premapped(sq->vq);
> + if (err) {
> + kfree(sq->dmainfo.head);
> + return err;
> + }
> +
> + sq->dmainfo.free = NULL;
> +
> + sq->do_dma = true;
> +
> + for (i = 0; i < size; ++i) {
> + d = &sq->dmainfo.head[i];
> +
> + d->next = sq->dmainfo.free;
> + sq->dmainfo.free = d;
> + }
> +
> + return 0;
> +}
> +
> +static void virtnet_set_premapped(struct virtnet_info *vi)
> +{
> + int i;
>
> for (i = 0; i < vi->max_queue_pairs; i++) {
> - if (virtqueue_set_dma_premapped(vi->rq[i].vq))
> + if (!virtnet_sq_set_premapped(&vi->sq[i]))
> + vi->sq[i].do_dma = true;
> +
> + /* disable for big mode */
> + if (!vi->mergeable_rx_bufs && vi->big_packets)
> continue;
>
> - vi->rq[i].do_dma = true;
> + if (!virtqueue_set_dma_premapped(vi->rq[i].vq))
> + vi->rq[i].do_dma = true;
> + }
> +}
> +
> +static struct virtnet_sq_dma *virtnet_sq_map_sg(struct virtnet_sq *sq, int nents, void *data)
> +{
> + struct virtnet_sq_dma *d, *head;
> + struct scatterlist *sg;
> + int i;
> +
> + head = NULL;
> +
> + for_each_sg(sq->sg, sg, nents, i) {
> + sg->dma_address = virtqueue_dma_map_single_attrs(sq->vq, sg_virt(sg),
> + sg->length,
> + DMA_TO_DEVICE, 0);
> + if (virtqueue_dma_mapping_error(sq->vq, sg->dma_address))
> + goto err;
> +
> + d = sq->dmainfo.free;
> + sq->dmainfo.free = d->next;
> +
> + d->addr = sg->dma_address;
> + d->len = sg->length;
> +
> + d->next = head;
> + head = d;
It's really a pity that we need to duplicate those DMA metata twice.
Could we invent a new API to just fetch it from the virtio core?
> + }
> +
> + head->data = data;
> +
> + return (void *)((unsigned long)head | ((unsigned long)data & VIRTIO_XMIT_DATA_MASK));
If we packed everything into dmainfo, we can leave the type (XDP vs
skb) there to avoid trick like packing it into the pointer here?
Thanks
