XDP xmit uses virtio dma api for DMA operations. No longer let virtio core manage DMA address.
To record the DMA address, allocate a space in the xdp_frame headroom to store the DMA address. Introduce virtnet_return_xdp_frame() to release the xdp frame and complete the dma unmap operation. Signed-off-by: Xuan Zhuo <[email protected]> --- drivers/net/virtio_net.c | 42 +++++++++++++++++++++++++++++++++------- 1 file changed, 35 insertions(+), 7 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index a801ea40908f..0efbf7992a95 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -321,6 +321,20 @@ static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask) return p; } +static void virtnet_return_xdp_frame(struct send_queue *sq, + struct xdp_frame *frame) +{ + struct virtnet_info *vi = sq->vq->vdev->priv; + dma_addr_t *p_addr, addr; + + p_addr = frame->data - sizeof(*p_addr); + addr = *p_addr; + + virtio_dma_unmap(&vi->vdev->dev, addr, frame->len, DMA_TO_DEVICE); + + xdp_return_frame(frame); +} + static void virtqueue_napi_schedule(struct napi_struct *napi, struct virtqueue *vq) { @@ -504,9 +518,11 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi, struct xdp_frame *xdpf) { struct virtio_net_hdr_mrg_rxbuf *hdr; + struct device *dev = &vi->vdev->dev; + dma_addr_t addr, *p_addr; int err; - if (unlikely(xdpf->headroom < vi->hdr_len)) + if (unlikely(xdpf->headroom < vi->hdr_len + sizeof(addr))) return -EOVERFLOW; /* Make room for virtqueue hdr (also change xdpf->headroom?) */ @@ -516,10 +532,21 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi, memset(hdr, 0, vi->hdr_len); xdpf->len += vi->hdr_len; - sg_init_one(sq->sg, xdpf->data, xdpf->len); + p_addr = xdpf->data - sizeof(addr); + + addr = virtio_dma_map(dev, xdpf->data, xdpf->len, DMA_TO_DEVICE); + + if (virtio_dma_mapping_error(dev, addr)) + return -ENOMEM; + + *p_addr = addr; + + sg_init_table(sq->sg, 1); + sq->sg->dma_address = addr; + sq->sg->length = xdpf->len; - err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp_to_ptr(xdpf), - GFP_ATOMIC); + err = virtqueue_add_outbuf_premapped(sq->vq, sq->sg, 1, + xdp_to_ptr(xdpf), GFP_ATOMIC); if (unlikely(err)) return -ENOSPC; /* Caller handle free/refcnt */ @@ -600,7 +627,7 @@ static int virtnet_xdp_xmit(struct net_device *dev, struct xdp_frame *frame = ptr_to_xdp(ptr); bytes += frame->len; - xdp_return_frame(frame); + virtnet_return_xdp_frame(sq, frame); } else { struct sk_buff *skb = ptr; @@ -1486,7 +1513,7 @@ static void free_old_xmit_skbs(struct send_queue *sq, bool in_napi) struct xdp_frame *frame = ptr_to_xdp(ptr); bytes += frame->len; - xdp_return_frame(frame); + virtnet_return_xdp_frame(sq, frame); } packets++; } @@ -2815,7 +2842,8 @@ static void free_unused_bufs(struct virtnet_info *vi) if (!is_xdp_frame(buf)) dev_kfree_skb(buf); else - xdp_return_frame(ptr_to_xdp(buf)); + virtnet_return_xdp_frame(vi->sq + i, + ptr_to_xdp(buf)); } } -- 2.31.0 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
