On Tue, Jan 30, 2024 at 7:43 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_net.c | 167 ++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 163 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 226ab830870e..cf0c67380b07 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -46,6 +46,7 @@ module_param(napi_tx, bool, 0644);
> #define VIRTIO_XDP_REDIR BIT(1)
>
> #define VIRTIO_XDP_FLAG BIT(0)
> +#define VIRTIO_DMA_FLAG BIT(1)
>
> /* RX packet size EWMA. The average packet size is used to determine the packet
> * buffer size when refilling RX rings. As the entire RX ring may be refilled
> @@ -140,6 +141,21 @@ struct virtnet_rq_dma {
> u16 need_sync;
> };
>
> +struct virtnet_sq_dma {
> + union {
> + struct virtnet_sq_dma *next;
> + void *data;
> + };
> + dma_addr_t addr;
> + u32 len;
> + bool is_tail;
> +};
> +
> +struct virtnet_sq_dma_head {
> + struct virtnet_sq_dma *free;
> + struct virtnet_sq_dma *head;
Any reason the head must be a pointer instead of a simple index?
> +};
> +
> /* Internal representation of a send virtqueue */
> struct send_queue {
> /* Virtqueue associated with this send _queue */
> @@ -159,6 +175,8 @@ struct send_queue {
>
> /* Record whether sq is in reset state. */
> bool reset;
> +
> + struct virtnet_sq_dma_head dmainfo;
> };
>
> /* Internal representation of a receive virtqueue */
> @@ -348,6 +366,131 @@ static struct xdp_frame *ptr_to_xdp(void *ptr)
> return (struct xdp_frame *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG);
> }
>
> +static inline void *virtnet_sq_unmap(struct send_queue *sq, void *data)
> +{
> + struct virtnet_sq_dma *head, *tail;
> +
> + if (!((unsigned long)data & VIRTIO_DMA_FLAG))
> + return data;
> +
> + head = (void *)((unsigned long)data & ~VIRTIO_DMA_FLAG);
> +
> + tail = head;
> +
> + while (true) {
> + virtqueue_dma_unmap_page_attrs(sq->vq, tail->addr, tail->len,
> + DMA_TO_DEVICE, 0);
> +
> + if (tail->is_tail)
> + break;
> +
> + tail = tail->next;
> + }
> +
> + data = tail->data;
> + tail->is_tail = false;
> +
> + tail->next = sq->dmainfo.free;
> + sq->dmainfo.free = head;
> +
> + return data;
> +}
> +
> +static void *virtnet_sq_dma_splice(struct send_queue *sq,
> + struct virtnet_sq_dma *head,
> + struct virtnet_sq_dma *tail,
> + void *data)
> +{
> + sq->dmainfo.free = tail->next;
> +
> + tail->is_tail = true;
> + tail->data = data;
> +
> + head = (void *)((unsigned long)head | VIRTIO_DMA_FLAG);
> +
> + return head;
> +}
> +
> +static struct virtnet_sq_dma *virtnet_sq_map_sg(struct send_queue *sq, int nents, void *data)
> +{
> + struct virtnet_sq_dma *head, *tail, *p;
> + struct scatterlist *sg;
> + dma_addr_t addr;
> + int i;
> +
> + head = sq->dmainfo.free;
> + p = head;
> +
> + tail = NULL;
> +
> + for_each_sg(sq->sg, sg, nents, i) {
> + addr = virtqueue_dma_map_page_attrs(sq->vq, sg_page(sg),
> + sg->offset, sg->length,
> + DMA_TO_DEVICE, 0);
> + if (virtqueue_dma_mapping_error(sq->vq, addr))
> + goto err;
> +
> + sg->dma_address = addr;
> +
> + tail = p;
> + tail->addr = sg->dma_address;
> + tail->len = sg->length;
> +
> + p = p->next;
> + }
> +
> + return virtnet_sq_dma_splice(sq, head, tail, data);
> +
> +err:
> + if (tail)
> + virtnet_sq_unmap(sq, virtnet_sq_dma_splice(sq, head, tail, data));
> +
> + return NULL;
> +}
> +
> +static int virtnet_add_outbuf(struct send_queue *sq, u32 num, void *data)
> +{
> + int ret;
> +
> + if (sq->vq->premapped) {
> + data = virtnet_sq_map_sg(sq, num, data);
> + if (!data)
> + return -ENOMEM;
> + }
> +
> + ret = virtqueue_add_outbuf(sq->vq, sq->sg, num, data, GFP_ATOMIC);
> + if (ret && sq->vq->premapped)
> + virtnet_sq_unmap(sq, data);
> +
> + return ret;
> +}
> +
> +static int virtnet_sq_init_dma_mate(struct send_queue *sq)
> +{
> + struct virtnet_sq_dma *d;
> + int size, i;
> +
> + size = virtqueue_get_vring_size(sq->vq);
> +
> + size += MAX_SKB_FRAGS + 2;
Is this enough for the case where an indirect descriptor is used?
Thanks
