#include <linux/module.h>
#include <linux/virtio.h>
#include <linux/virtio_net.h>
+#include <linux/bpf.h>
#include <linux/scatterlist.h>
#include <linux/if_vlan.h>
#include <linux/slab.h>
struct napi_struct napi;
+ struct bpf_prog __rcu *xdp_prog;
+
/* Chain pages by the private ptr. */
struct page *pages;
/* # of queue pairs currently used by the driver */
u16 curr_queue_pairs;
+ /* # of XDP queue pairs currently used by the driver */
+ u16 xdp_queue_pairs;
+
/* I like... big packets and I cannot lie! */
bool big_packets;
return skb;
}
+static void virtnet_xdp_xmit(struct virtnet_info *vi,
+ struct receive_queue *rq,
+ struct send_queue *sq,
+ struct xdp_buff *xdp)
+{
+ struct page *page = virt_to_head_page(xdp->data);
+ struct virtio_net_hdr_mrg_rxbuf *hdr;
+ unsigned int num_sg, len;
+ void *xdp_sent;
+ int err;
+
+ /* Free up any pending old buffers before queueing new ones. */
+ while ((xdp_sent = virtqueue_get_buf(sq->vq, &len)) != NULL) {
+ struct page *sent_page = virt_to_head_page(xdp_sent);
+ put_page(sent_page);
+ }
+
+ /* Zero header and leave csum up to XDP layers */
+ hdr = xdp->data;
+ memset(hdr, 0, vi->hdr_len);
+
+ num_sg = 1;
+ sg_init_one(sq->sg, xdp->data, xdp->data_end - xdp->data);
+ err = virtqueue_add_outbuf(sq->vq, sq->sg, num_sg,
+ xdp->data, GFP_ATOMIC);
+ if (unlikely(err)) {
+ put_page(page);
+ return; // On error abort to avoid unnecessary kick
+ }
+
+ virtqueue_kick(sq->vq);
+}
+
+static u32 do_xdp_prog(struct virtnet_info *vi,
+ struct receive_queue *rq,
+ struct bpf_prog *xdp_prog,
+ struct page *page, int offset, int len)
+{
+ int hdr_padded_len;
+ struct xdp_buff xdp;
+ unsigned int qp;
+ u32 act;
+ u8 *buf;
+
+ buf = page_address(page) + offset;
+
+ if (vi->mergeable_rx_bufs)
+ hdr_padded_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+ else
+ hdr_padded_len = sizeof(struct padded_vnet_hdr);
+
+ xdp.data = buf + hdr_padded_len;
+ xdp.data_end = xdp.data + (len - vi->hdr_len);
+
+ act = bpf_prog_run_xdp(xdp_prog, &xdp);
+ switch (act) {
+ case XDP_PASS:
+ return XDP_PASS;
+ case XDP_TX:
+ qp = vi->curr_queue_pairs -
+ vi->xdp_queue_pairs +
+ smp_processor_id();
+ xdp.data = buf + (vi->mergeable_rx_bufs ? 0 : 4);
+ virtnet_xdp_xmit(vi, rq, &vi->sq[qp], &xdp);
+ return XDP_TX;
+ default:
+ bpf_warn_invalid_xdp_action(act);
+ case XDP_ABORTED:
+ case XDP_DROP:
+ return XDP_DROP;
+ }
+}
+
static struct sk_buff *receive_small(struct virtnet_info *vi, void *buf, unsigned int len)
{
struct sk_buff * skb = buf;
return NULL;
}
+/* The conditions to enable XDP should preclude the underlying device from
+ * sending packets across multiple buffers (num_buf > 1). However per spec
+ * it does not appear to be illegal to do so but rather just against convention.
+ * So in order to avoid making a system unresponsive the packets are pushed
+ * into a page and the XDP program is run. This will be extremely slow and we
+ * push a warning to the user to fix this as soon as possible. Fixing this may
+ * require resolving the underlying hardware to determine why multiple buffers
+ * are being received or simply loading the XDP program in the ingress stack
+ * after the skb is built because there is no advantage to running it here
+ * anymore.
+ */
+static struct page *xdp_linearize_page(struct receive_queue *rq,
+ u16 *num_buf,
+ struct page *p,
+ int offset,
+ unsigned int *len)
+{
+ struct page *page = alloc_page(GFP_ATOMIC);
+ unsigned int page_off = 0;
+
+ if (!page)
+ return NULL;
+
+ memcpy(page_address(page) + page_off, page_address(p) + offset, *len);
+ page_off += *len;
+
+ while (--*num_buf) {
+ unsigned int buflen;
+ unsigned long ctx;
+ void *buf;
+ int off;
+
+ ctx = (unsigned long)virtqueue_get_buf(rq->vq, &buflen);
+ if (unlikely(!ctx))
+ goto err_buf;
+
+ buf = mergeable_ctx_to_buf_address(ctx);
+ p = virt_to_head_page(buf);
+ off = buf - page_address(p);
+
+ /* guard against a misconfigured or uncooperative backend that
+ * is sending packet larger than the MTU.
+ */
+ if ((page_off + buflen) > PAGE_SIZE) {
+ put_page(p);
+ goto err_buf;
+ }
+
+ memcpy(page_address(page) + page_off,
+ page_address(p) + off, buflen);
+ page_off += buflen;
+ put_page(p);
+ }
+
+ *len = page_off;
+ return page;
+err_buf:
+ __free_pages(page, 0);
+ return NULL;
+}
+
static struct sk_buff *receive_mergeable(struct net_device *dev,
struct virtnet_info *vi,
struct receive_queue *rq,
u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
struct page *page = virt_to_head_page(buf);
int offset = buf - page_address(page);
- unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
+ struct sk_buff *head_skb, *curr_skb;
+ struct bpf_prog *xdp_prog;
+ unsigned int truesize;
+
+ head_skb = NULL;
+
+ rcu_read_lock();
+ xdp_prog = rcu_dereference(rq->xdp_prog);
+ if (xdp_prog) {
+ struct page *xdp_page;
+ u32 act;
+
+ /* This happens when rx buffer size is underestimated */
+ if (unlikely(num_buf > 1)) {
+ /* linearize data for XDP */
+ xdp_page = xdp_linearize_page(rq, &num_buf,
+ page, offset, &len);
+ if (!xdp_page)
+ goto err_xdp;
+ offset = 0;
+ } else {
+ xdp_page = page;
+ }
- struct sk_buff *head_skb = page_to_skb(vi, rq, page, offset, len,
- truesize);
- struct sk_buff *curr_skb = head_skb;
+ /* Transient failure which in theory could occur if
+ * in-flight packets from before XDP was enabled reach
+ * the receive path after XDP is loaded. In practice I
+ * was not able to create this condition.
+ */
+ if (unlikely(hdr->hdr.gso_type))
+ goto err_xdp;
+
+ act = do_xdp_prog(vi, rq, xdp_prog, xdp_page, offset, len);
+ switch (act) {
+ case XDP_PASS:
+ /* We can only create skb based on xdp_page. */
+ if (unlikely(xdp_page != page)) {
+ rcu_read_unlock();
+ put_page(page);
+ head_skb = page_to_skb(vi, rq, xdp_page,
+ 0, len, PAGE_SIZE);
+ ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len);
+ return head_skb;
+ }
+ break;
+ case XDP_TX:
+ ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len);
+ if (unlikely(xdp_page != page))
+ goto err_xdp;
+ rcu_read_unlock();
+ goto xdp_xmit;
+ case XDP_DROP:
+ default:
+ if (unlikely(xdp_page != page))
+ __free_pages(xdp_page, 0);
+ ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len);
+ goto err_xdp;
+ }
+ }
+ rcu_read_unlock();
+
+ truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
+ head_skb = page_to_skb(vi, rq, page, offset, len, truesize);
+ curr_skb = head_skb;
if (unlikely(!curr_skb))
goto err_skb;
ewma_pkt_len_add(&rq->mrg_avg_pkt_len, head_skb->len);
return head_skb;
+err_xdp:
+ rcu_read_unlock();
err_skb:
put_page(page);
while (--num_buf) {
err_buf:
dev->stats.rx_dropped++;
dev_kfree_skb(head_skb);
+xdp_xmit:
return NULL;
}
if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
return -EINVAL;
+ /* For now we don't support modifying channels while XDP is loaded
+ * also when XDP is loaded all RX queues have XDP programs so we only
+ * need to check a single RX queue.
+ */
+ if (vi->rq[0].xdp_prog)
+ return -EINVAL;
+
get_online_cpus();
err = virtnet_set_queues(vi, queue_pairs);
if (!err) {
.set_settings = virtnet_set_settings,
};
+static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog)
+{
+ unsigned long int max_sz = PAGE_SIZE - sizeof(struct padded_vnet_hdr);
+ struct virtnet_info *vi = netdev_priv(dev);
+ struct bpf_prog *old_prog;
+ u16 xdp_qp = 0, curr_qp;
+ int i, err;
+
+ if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) ||
+ virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6) ||
+ virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_ECN) ||
+ virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_UFO)) {
+ netdev_warn(dev, "can't set XDP while host is implementing LRO, disable LRO first\n");
+ return -EOPNOTSUPP;
+ }
+
+ if (vi->mergeable_rx_bufs && !vi->any_header_sg) {
+ netdev_warn(dev, "XDP expects header/data in single page, any_header_sg required\n");
+ return -EINVAL;
+ }
+
+ if (dev->mtu > max_sz) {
+ netdev_warn(dev, "XDP requires MTU less than %lu\n", max_sz);
+ return -EINVAL;
+ }
+
+ curr_qp = vi->curr_queue_pairs - vi->xdp_queue_pairs;
+ if (prog)
+ xdp_qp = nr_cpu_ids;
+
+ /* XDP requires extra queues for XDP_TX */
+ if (curr_qp + xdp_qp > vi->max_queue_pairs) {
+ netdev_warn(dev, "request %i queues but max is %i\n",
+ curr_qp + xdp_qp, vi->max_queue_pairs);
+ return -ENOMEM;
+ }
+
+ err = virtnet_set_queues(vi, curr_qp + xdp_qp);
+ if (err) {
+ dev_warn(&dev->dev, "XDP Device queue allocation failure.\n");
+ return err;
+ }
+
+ if (prog) {
+ prog = bpf_prog_add(prog, vi->max_queue_pairs - 1);
+ if (IS_ERR(prog)) {
+ virtnet_set_queues(vi, curr_qp);
+ return PTR_ERR(prog);
+ }
+ }
+
+ vi->xdp_queue_pairs = xdp_qp;
+ netif_set_real_num_rx_queues(dev, curr_qp + xdp_qp);
+
+ for (i = 0; i < vi->max_queue_pairs; i++) {
+ old_prog = rtnl_dereference(vi->rq[i].xdp_prog);
+ rcu_assign_pointer(vi->rq[i].xdp_prog, prog);
+ if (old_prog)
+ bpf_prog_put(old_prog);
+ }
+
+ return 0;
+}
+
+static bool virtnet_xdp_query(struct net_device *dev)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+ int i;
+
+ for (i = 0; i < vi->max_queue_pairs; i++) {
+ if (vi->rq[i].xdp_prog)
+ return true;
+ }
+ return false;
+}
+
+static int virtnet_xdp(struct net_device *dev, struct netdev_xdp *xdp)
+{
+ switch (xdp->command) {
+ case XDP_SETUP_PROG:
+ return virtnet_xdp_set(dev, xdp->prog);
+ case XDP_QUERY_PROG:
+ xdp->prog_attached = virtnet_xdp_query(dev);
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
static const struct net_device_ops virtnet_netdev = {
.ndo_open = virtnet_open,
.ndo_stop = virtnet_close,
#ifdef CONFIG_NET_RX_BUSY_POLL
.ndo_busy_poll = virtnet_busy_poll,
#endif
+ .ndo_xdp = virtnet_xdp,
};
static void virtnet_config_changed_work(struct work_struct *work)
static void free_receive_bufs(struct virtnet_info *vi)
{
+ struct bpf_prog *old_prog;
int i;
+ rtnl_lock();
for (i = 0; i < vi->max_queue_pairs; i++) {
while (vi->rq[i].pages)
__free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
+
+ old_prog = rtnl_dereference(vi->rq[i].xdp_prog);
+ RCU_INIT_POINTER(vi->rq[i].xdp_prog, NULL);
+ if (old_prog)
+ bpf_prog_put(old_prog);
}
+ rtnl_unlock();
}
static void free_receive_page_frags(struct virtnet_info *vi)
put_page(vi->rq[i].alloc_frag.page);
}
+static bool is_xdp_queue(struct virtnet_info *vi, int q)
+{
+ if (q < (vi->curr_queue_pairs - vi->xdp_queue_pairs))
+ return false;
+ else if (q < vi->curr_queue_pairs)
+ return true;
+ else
+ return false;
+}
+
static void free_unused_bufs(struct virtnet_info *vi)
{
void *buf;
for (i = 0; i < vi->max_queue_pairs; i++) {
struct virtqueue *vq = vi->sq[i].vq;
- while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
- dev_kfree_skb(buf);
+ while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
+ if (!is_xdp_queue(vi, i))
+ dev_kfree_skb(buf);
+ else
+ put_page(virt_to_head_page(buf));
+ }
}
for (i = 0; i < vi->max_queue_pairs; i++) {
goto free_unregister_netdev;
}
- virtnet_set_affinity(vi);
+ rtnl_lock();
+ virtnet_set_queues(vi, vi->curr_queue_pairs);
+ rtnl_unlock();
/* Assume link up if device can't report link status,
otherwise get link status from config. */
projects / mirror_ubuntu-bionic-kernel.git / blobdiff