Merry Xmas and a Happy New year to all: This series tries to fixes several issues for virtio-net XDP which could be categorized into several parts: - fix several issues during XDP linearizing - allow csumed packet to work for XDP_PASS - make EWMA rxbuf size estimation works for XDP - forbid XDP when GUEST_UFO is support - remove big packet XDP support - add XDP support or small buffer Please see individual patches for details. Thanks Jason Wang (9): virtio-net: remove the warning before XDP linearizing virtio-net: correctly xmit linearized page on XDP_TX virtio-net: fix page miscount during XDP linearizing virtio-net: correctly handle XDP_PASS for linearized packets virtio-net: unbreak csumed packets for XDP_PASS virtio-net: make rx buf size estimation works for XDP virtio-net: forbid XDP when VIRTIO_NET_F_GUEST_UFO is support virtio-net: remove big packet XDP codes virtio-net: XDP support for small buffers drivers/net/virtio_net.c | 172 ++++++++++++++++++++++++++++------------------- 1 file changed, 102 insertions(+), 70 deletions(-) -- 2.7.4
Jason Wang
2016-Dec-23 14:37 UTC
[PATCH net 1/9] virtio-net: remove the warning before XDP linearizing
Since we use EWMA to estimate the size of rx buffer. When rx buffer size is underestimated, it's usual to have a packet with more than one buffers. Consider this is not a bug, remove the warning and correct the comment before XDP linearizing. Cc: John Fastabend <john.r.fastabend at intel.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 08327e0..1067253 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -552,14 +552,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, struct page *xdp_page; u32 act; - /* No known backend devices should send packets with - * more than a single buffer when XDP conditions are - * met. However it is not strictly illegal so the case - * is handled as an exception and a warning is thrown. - */ + /* This happens when rx buffer size is underestimated */ if (unlikely(num_buf > 1)) { - bpf_warn_invalid_xdp_buffer(); - /* linearize data for XDP */ xdp_page = xdp_linearize_page(rq, num_buf, page, offset, &len); -- 2.7.4
Jason Wang
2016-Dec-23 14:37 UTC
[PATCH net 2/9] virtio-net: correctly xmit linearized page on XDP_TX
After we linearize page, we should xmit this page instead of the page of first buffer which may lead unexpected result. With this patch, we can see correct packet during XDP_TX. Cc: John Fastabend <john.r.fastabend at intel.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 1067253..fe4562d 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -572,7 +572,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags)) goto err_xdp; - act = do_xdp_prog(vi, rq, xdp_prog, page, offset, len); + act = do_xdp_prog(vi, rq, xdp_prog, xdp_page, offset, len); switch (act) { case XDP_PASS: if (unlikely(xdp_page != page)) -- 2.7.4
Jason Wang
2016-Dec-23 14:37 UTC
[PATCH net 3/9] virtio-net: fix page miscount during XDP linearizing
We don't put page during linearizing, the would cause leaking when xmit through XDP_TX or the packet exceeds PAGE_SIZE. Fix them by put page accordingly. Also decrease the number of buffers during linearizing to make sure caller can free buffers correctly when packet exceeds PAGE_SIZE. With this patch, we won't get OOM after linearize huge number of packets. Cc: John Fastabend <john.r.fastabend at intel.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index fe4562d..58ad40e 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -483,7 +483,7 @@ static struct sk_buff *receive_big(struct net_device *dev, * anymore. */ static struct page *xdp_linearize_page(struct receive_queue *rq, - u16 num_buf, + u16 *num_buf, struct page *p, int offset, unsigned int *len) @@ -497,7 +497,7 @@ static struct page *xdp_linearize_page(struct receive_queue *rq, memcpy(page_address(page) + page_off, page_address(p) + offset, *len); page_off += *len; - while (--num_buf) { + while (--*num_buf) { unsigned int buflen; unsigned long ctx; void *buf; @@ -507,19 +507,22 @@ static struct page *xdp_linearize_page(struct receive_queue *rq, 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) + if ((page_off + buflen) > PAGE_SIZE) { + put_page(p); goto err_buf; - - buf = mergeable_ctx_to_buf_address(ctx); - p = virt_to_head_page(buf); - off = buf - page_address(p); + } memcpy(page_address(page) + page_off, page_address(p) + off, buflen); page_off += buflen; + put_page(p); } *len = page_off; @@ -555,7 +558,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, /* 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, + xdp_page = xdp_linearize_page(rq, &num_buf, page, offset, &len); if (!xdp_page) goto err_xdp; -- 2.7.4
Jason Wang
2016-Dec-23 14:37 UTC
[PATCH net 4/9] virtio-net: correctly handle XDP_PASS for linearized packets
When XDP_PASS were determined for linearized packets, we try to get new buffers in the virtqueue and build skbs from them. This is wrong, we should create skbs based on existed buffers instead. Fixing them by creating skb based on xdp_page. With this patch "ping 192.168.100.4 -s 3900 -M do" works for XDP_PASS. Cc: John Fastabend <john.r.fastabend at intel.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 58ad40e..470293e 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -578,8 +578,14 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, act = do_xdp_prog(vi, rq, xdp_prog, xdp_page, offset, len); switch (act) { case XDP_PASS: - if (unlikely(xdp_page != page)) - __free_pages(xdp_page, 0); + /* 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); + return head_skb; + } break; case XDP_TX: if (unlikely(xdp_page != page)) -- 2.7.4
Jason Wang
2016-Dec-23 14:37 UTC
[PATCH net 5/9] virtio-net: unbreak csumed packets for XDP_PASS
We drop csumed packet when do XDP for packets. This breaks XDP_PASS when GUEST_CSUM is supported. Fix this by allowing csum flag to be set. With this patch, simple TCP works for XDP_PASS. Cc: John Fastabend <john.r.fastabend at intel.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 470293e..0778dc8 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -440,7 +440,7 @@ static struct sk_buff *receive_big(struct net_device *dev, struct virtio_net_hdr_mrg_rxbuf *hdr = buf; u32 act; - if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags)) + if (unlikely(hdr->hdr.gso_type)) goto err_xdp; act = do_xdp_prog(vi, rq, xdp_prog, page, 0, len); switch (act) { @@ -572,7 +572,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, * the receive path after XDP is loaded. In practice I * was not able to create this condition. */ - if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags)) + if (unlikely(hdr->hdr.gso_type)) goto err_xdp; act = do_xdp_prog(vi, rq, xdp_prog, xdp_page, offset, len); -- 2.7.4
Jason Wang
2016-Dec-23 14:37 UTC
[PATCH net 6/9] virtio-net: make rx buf size estimation works for XDP
We don't update ewma rx buf size in the case of XDP. This will lead underestimation of rx buf size which causes host to produce more than one buffers. This will greatly increase the possibility of XDP page linearization. Cc: John Fastabend <john.r.fastabend at intel.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 0778dc8..77ae358 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -584,10 +584,12 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 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(); @@ -596,6 +598,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, default: if (unlikely(xdp_page != page)) __free_pages(xdp_page, 0); + ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len); goto err_xdp; } } -- 2.7.4
Jason Wang
2016-Dec-23 14:37 UTC
[PATCH net 7/9] virtio-net: forbid XDP when VIRTIO_NET_F_GUEST_UFO is support
When VIRTIO_NET_F_GUEST_UFO is negotiated, host could still send UFO packet that exceeds a single page which could not be handled correctly by XDP. So this patch forbids setting XDP when GUEST_UFO is supported. While at it, forbid XDP for ECN (which comes only from GRO) too to prevent user from misconfiguration. Cc: John Fastabend <john.r.fastabend at intel.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 77ae358..c1f66d8 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1684,7 +1684,9 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog) 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_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; } -- 2.7.4
Now we in fact don't allow XDP for big packets, remove its codes. Cc: John Fastabend <john.r.fastabend at intel.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 44 +++----------------------------------------- 1 file changed, 3 insertions(+), 41 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index c1f66d8..e53365a8 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -344,11 +344,7 @@ static void virtnet_xdp_xmit(struct virtnet_info *vi, /* 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); - - if (vi->mergeable_rx_bufs) - put_page(sent_page); - else - give_pages(rq, sent_page); + put_page(sent_page); } /* Zero header and leave csum up to XDP layers */ @@ -360,15 +356,8 @@ static void virtnet_xdp_xmit(struct virtnet_info *vi, err = virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, xdp->data, GFP_ATOMIC); if (unlikely(err)) { - if (vi->mergeable_rx_bufs) - put_page(page); - else - give_pages(rq, page); + put_page(page); return; // On error abort to avoid unnecessary kick - } else if (!vi->mergeable_rx_bufs) { - /* If not mergeable bufs must be big packets so cleanup pages */ - give_pages(rq, (struct page *)page->private); - page->private = 0; } virtqueue_kick(sq->vq); @@ -430,44 +419,17 @@ static struct sk_buff *receive_big(struct net_device *dev, void *buf, unsigned int len) { - struct bpf_prog *xdp_prog; struct page *page = buf; - struct sk_buff *skb; - - rcu_read_lock(); - xdp_prog = rcu_dereference(rq->xdp_prog); - if (xdp_prog) { - struct virtio_net_hdr_mrg_rxbuf *hdr = buf; - u32 act; - - if (unlikely(hdr->hdr.gso_type)) - goto err_xdp; - act = do_xdp_prog(vi, rq, xdp_prog, page, 0, len); - switch (act) { - case XDP_PASS: - break; - case XDP_TX: - rcu_read_unlock(); - goto xdp_xmit; - case XDP_DROP: - default: - goto err_xdp; - } - } - rcu_read_unlock(); + struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE); - skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE); if (unlikely(!skb)) goto err; return skb; -err_xdp: - rcu_read_unlock(); err: dev->stats.rx_dropped++; give_pages(rq, page); -xdp_xmit: return NULL; } -- 2.7.4
Jason Wang
2016-Dec-23 14:37 UTC
[PATCH net 9/9] virtio-net: XDP support for small buffers
Commit f600b6905015 ("virtio_net: Add XDP support") leaves the case of small receive buffer untouched. This will confuse the user who want to set XDP but use small buffers. Other than forbid XDP in small buffer mode, let's make it work. XDP then can only work at skb->data since virtio-net create skbs during refill, this is sub optimal which could be optimized in the future. Cc: John Fastabend <john.r.fastabend at intel.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 112 ++++++++++++++++++++++++++++++++++++----------- 1 file changed, 87 insertions(+), 25 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index e53365a8..5deeda6 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -333,9 +333,9 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, static void virtnet_xdp_xmit(struct virtnet_info *vi, struct receive_queue *rq, struct send_queue *sq, - struct xdp_buff *xdp) + struct xdp_buff *xdp, + void *data) { - struct page *page = virt_to_head_page(xdp->data); struct virtio_net_hdr_mrg_rxbuf *hdr; unsigned int num_sg, len; void *xdp_sent; @@ -343,20 +343,45 @@ static void virtnet_xdp_xmit(struct virtnet_info *vi, /* 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); + if (vi->mergeable_rx_bufs) { + struct page *sent_page = virt_to_head_page(xdp_sent); + + put_page(sent_page); + } else { /* small buffer */ + struct sk_buff *skb = xdp_sent; + + kfree_skb(skb); + } } - /* Zero header and leave csum up to XDP layers */ - hdr = xdp->data; - memset(hdr, 0, vi->hdr_len); + if (vi->mergeable_rx_bufs) { + /* 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); + } else { /* small buffer */ + struct sk_buff *skb = data; - num_sg = 1; - sg_init_one(sq->sg, xdp->data, xdp->data_end - xdp->data); + /* Zero header and leave csum up to XDP layers */ + hdr = skb_vnet_hdr(skb); + memset(hdr, 0, vi->hdr_len); + + num_sg = 2; + sg_init_table(sq->sg, 2); + sg_set_buf(sq->sg, hdr, vi->hdr_len); + skb_to_sgvec(skb, sq->sg + 1, 0, skb->len); + } err = virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, - xdp->data, GFP_ATOMIC); + data, GFP_ATOMIC); if (unlikely(err)) { - put_page(page); + if (vi->mergeable_rx_bufs) { + struct page *page = virt_to_head_page(xdp->data); + + put_page(page); + } else /* small buffer */ + kfree_skb(data); return; // On error abort to avoid unnecessary kick } @@ -366,23 +391,26 @@ static void virtnet_xdp_xmit(struct virtnet_info *vi, 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) + void *data, int len) { int hdr_padded_len; struct xdp_buff xdp; + void *buf; unsigned int qp; u32 act; - u8 *buf; - - buf = page_address(page) + offset; - if (vi->mergeable_rx_bufs) + 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 = data + hdr_padded_len; + xdp.data_end = xdp.data + (len - vi->hdr_len); + buf = data; + } else { /* small buffers */ + struct sk_buff *skb = data; - xdp.data = buf + hdr_padded_len; - xdp.data_end = xdp.data + (len - vi->hdr_len); + xdp.data = skb->data; + xdp.data_end = xdp.data + len; + buf = skb->data; + } act = bpf_prog_run_xdp(xdp_prog, &xdp); switch (act) { @@ -392,8 +420,8 @@ static u32 do_xdp_prog(struct virtnet_info *vi, 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); + xdp.data = buf; + virtnet_xdp_xmit(vi, rq, &vi->sq[qp], &xdp, data); return XDP_TX; default: bpf_warn_invalid_xdp_action(act); @@ -403,14 +431,47 @@ static u32 do_xdp_prog(struct virtnet_info *vi, } } -static struct sk_buff *receive_small(struct virtnet_info *vi, void *buf, unsigned int len) +static struct sk_buff *receive_small(struct net_device *dev, + struct virtnet_info *vi, + struct receive_queue *rq, + void *buf, unsigned int len) { struct sk_buff * skb = buf; + struct bpf_prog *xdp_prog; len -= vi->hdr_len; skb_trim(skb, len); + rcu_read_lock(); + xdp_prog = rcu_dereference(rq->xdp_prog); + if (xdp_prog) { + struct virtio_net_hdr_mrg_rxbuf *hdr = buf; + u32 act; + + if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags)) + goto err_xdp; + act = do_xdp_prog(vi, rq, xdp_prog, skb, len); + switch (act) { + case XDP_PASS: + break; + case XDP_TX: + rcu_read_unlock(); + goto xdp_xmit; + case XDP_DROP: + default: + goto err_xdp; + } + } + rcu_read_unlock(); + return skb; + +err_xdp: + rcu_read_unlock(); + dev->stats.rx_dropped++; + kfree_skb(skb); +xdp_xmit: + return NULL; } static struct sk_buff *receive_big(struct net_device *dev, @@ -537,7 +598,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, if (unlikely(hdr->hdr.gso_type)) goto err_xdp; - act = do_xdp_prog(vi, rq, xdp_prog, xdp_page, offset, len); + act = do_xdp_prog(vi, rq, xdp_prog, + page_address(xdp_page) + offset, len); switch (act) { case XDP_PASS: /* We can only create skb based on xdp_page. */ @@ -672,7 +734,7 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq, else if (vi->big_packets) skb = receive_big(dev, vi, rq, buf, len); else - skb = receive_small(vi, buf, len); + skb = receive_small(dev, vi, rq, buf, len); if (unlikely(!skb)) return; -- 2.7.4
John Fastabend
2016-Dec-23 15:47 UTC
[PATCH net 2/9] virtio-net: correctly xmit linearized page on XDP_TX
On 16-12-23 06:37 AM, Jason Wang wrote:> After we linearize page, we should xmit this page instead of the page > of first buffer which may lead unexpected result. With this patch, we > can see correct packet during XDP_TX. > > Cc: John Fastabend <john.r.fastabend at intel.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/net/virtio_net.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 1067253..fe4562d 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -572,7 +572,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags)) > goto err_xdp; > > - act = do_xdp_prog(vi, rq, xdp_prog, page, offset, len); > + act = do_xdp_prog(vi, rq, xdp_prog, xdp_page, offset, len); > switch (act) { > case XDP_PASS: > if (unlikely(xdp_page != page)) >Thanks clumsy merge conflict resolution between v4 and v6 versions :/ Acked-by: John Fastabend <john.r.fastabend at intel.com>
John Fastabend
2016-Dec-23 15:54 UTC
[PATCH net 3/9] virtio-net: fix page miscount during XDP linearizing
On 16-12-23 06:37 AM, Jason Wang wrote:> We don't put page during linearizing, the would cause leaking when > xmit through XDP_TX or the packet exceeds PAGE_SIZE. Fix them by > put page accordingly. Also decrease the number of buffers during > linearizing to make sure caller can free buffers correctly when packet > exceeds PAGE_SIZE. With this patch, we won't get OOM after linearize > huge number of packets. > > Cc: John Fastabend <john.r.fastabend at intel.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > ---Thanks! looks good. By the way do you happen to have any actual configuration where this path is hit? I obviously didn't test this very long other than a quick test with my hacked vhost driver. Acked-by: John Fastabend <john.r.fastabend at intel.com>
John Fastabend
2016-Dec-23 15:57 UTC
[PATCH net 4/9] virtio-net: correctly handle XDP_PASS for linearized packets
On 16-12-23 06:37 AM, Jason Wang wrote:> When XDP_PASS were determined for linearized packets, we try to get > new buffers in the virtqueue and build skbs from them. This is wrong, > we should create skbs based on existed buffers instead. Fixing them by > creating skb based on xdp_page. > > With this patch "ping 192.168.100.4 -s 3900 -M do" works for XDP_PASS. > > Cc: John Fastabend <john.r.fastabend at intel.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/net/virtio_net.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 58ad40e..470293e 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -578,8 +578,14 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > act = do_xdp_prog(vi, rq, xdp_prog, xdp_page, offset, len); > switch (act) { > case XDP_PASS: > - if (unlikely(xdp_page != page)) > - __free_pages(xdp_page, 0); > + /* 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); > + return head_skb; > + } > break; > case XDP_TX: > if (unlikely(xdp_page != page)) >Great thanks. This was likely working before because of the memory leak fixed in 3/9. Acked-by: John Fastabend <john.r.fastabend at intel.com>
John Fastabend
2016-Dec-23 15:58 UTC
[PATCH net 5/9] virtio-net: unbreak csumed packets for XDP_PASS
On 16-12-23 06:37 AM, Jason Wang wrote:> We drop csumed packet when do XDP for packets. This breaks > XDP_PASS when GUEST_CSUM is supported. Fix this by allowing csum flag > to be set. With this patch, simple TCP works for XDP_PASS. > > Cc: John Fastabend <john.r.fastabend at intel.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/net/virtio_net.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 470293e..0778dc8 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -440,7 +440,7 @@ static struct sk_buff *receive_big(struct net_device *dev, > struct virtio_net_hdr_mrg_rxbuf *hdr = buf; > u32 act; > > - if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags)) > + if (unlikely(hdr->hdr.gso_type)) > goto err_xdp; > act = do_xdp_prog(vi, rq, xdp_prog, page, 0, len); > switch (act) { > @@ -572,7 +572,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > * the receive path after XDP is loaded. In practice I > * was not able to create this condition. > */ > - if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags)) > + if (unlikely(hdr->hdr.gso_type)) > goto err_xdp; > > act = do_xdp_prog(vi, rq, xdp_prog, xdp_page, offset, len); >Acked-by: John Fastabend <john.r.fastabend at intel.com>
John Fastabend
2016-Dec-23 16:02 UTC
[PATCH net 6/9] virtio-net: make rx buf size estimation works for XDP
On 16-12-23 06:37 AM, Jason Wang wrote:> We don't update ewma rx buf size in the case of XDP. This will lead > underestimation of rx buf size which causes host to produce more than > one buffers. This will greatly increase the possibility of XDP page > linearization. > > Cc: John Fastabend <john.r.fastabend at intel.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/net/virtio_net.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 0778dc8..77ae358 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -584,10 +584,12 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > 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(); > @@ -596,6 +598,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > default: > if (unlikely(xdp_page != page)) > __free_pages(xdp_page, 0); > + ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len); > goto err_xdp; > } > } >Looks needed although I guess it will only be the case with MTU > ETH_DATA_LEN because of the clamp in get_mergeable_buf_len(). Although XDP setup allows MTU up to page_size - hdr so certainly will happen with ~MTU > 1500. I need to add some various MTU tests to my setup. Acked-by: John Fastabend <john.r.fastabend at intel.com>
John Fastabend
2016-Dec-23 16:02 UTC
[PATCH net 7/9] virtio-net: forbid XDP when VIRTIO_NET_F_GUEST_UFO is support
On 16-12-23 06:37 AM, Jason Wang wrote:> When VIRTIO_NET_F_GUEST_UFO is negotiated, host could still send UFO > packet that exceeds a single page which could not be handled > correctly by XDP. So this patch forbids setting XDP when GUEST_UFO is > supported. While at it, forbid XDP for ECN (which comes only from GRO) > too to prevent user from misconfiguration. > > Cc: John Fastabend <john.r.fastabend at intel.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/net/virtio_net.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 77ae358..c1f66d8 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -1684,7 +1684,9 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog) > 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_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; > } >Acked-by: John Fastabend <john.r.fastabend at intel.com>
John Fastabend
2016-Dec-23 16:51 UTC
[PATCH net 9/9] virtio-net: XDP support for small buffers
On 16-12-23 06:37 AM, Jason Wang wrote:> Commit f600b6905015 ("virtio_net: Add XDP support") leaves the case of > small receive buffer untouched. This will confuse the user who want to > set XDP but use small buffers. Other than forbid XDP in small buffer > mode, let's make it work. XDP then can only work at skb->data since > virtio-net create skbs during refill, this is sub optimal which could > be optimized in the future. > > Cc: John Fastabend <john.r.fastabend at intel.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > ---Looks good to me thanks! Acked-by: John Fastabend <john.r.fastabend at intel.com>
On 16-12-23 06:37 AM, Jason Wang wrote:> Merry Xmas and a Happy New year to all: > > This series tries to fixes several issues for virtio-net XDP which > could be categorized into several parts: > > - fix several issues during XDP linearizing > - allow csumed packet to work for XDP_PASS > - make EWMA rxbuf size estimation works for XDP > - forbid XDP when GUEST_UFO is support > - remove big packet XDP support > - add XDP support or small buffer > > Please see individual patches for details. > > Thanks > > Jason Wang (9): > virtio-net: remove the warning before XDP linearizing > virtio-net: correctly xmit linearized page on XDP_TX > virtio-net: fix page miscount during XDP linearizing > virtio-net: correctly handle XDP_PASS for linearized packets > virtio-net: unbreak csumed packets for XDP_PASS > virtio-net: make rx buf size estimation works for XDP > virtio-net: forbid XDP when VIRTIO_NET_F_GUEST_UFO is support > virtio-net: remove big packet XDP codes > virtio-net: XDP support for small buffers > > drivers/net/virtio_net.c | 172 ++++++++++++++++++++++++++++------------------- > 1 file changed, 102 insertions(+), 70 deletions(-) >Thanks a lot Jason. The last piece that is needed is support to complete XDP support is to get the adjust_head part correct. I'll send out a patch in a bit but will need to merge it on top of this set. .John
From: Jason Wang <jasowang at redhat.com> Date: Fri, 23 Dec 2016 22:37:23 +0800> Merry Xmas and a Happy New year to all: > > This series tries to fixes several issues for virtio-net XDP which > could be categorized into several parts: > > - fix several issues during XDP linearizing > - allow csumed packet to work for XDP_PASS > - make EWMA rxbuf size estimation works for XDP > - forbid XDP when GUEST_UFO is support > - remove big packet XDP support > - add XDP support or small buffer > > Please see individual patches for details.Series applied, thanks Jason.
Daniel Borkmann
2016-Dec-23 19:31 UTC
[PATCH net 1/9] virtio-net: remove the warning before XDP linearizing
Hi Jason, On 12/23/2016 03:37 PM, Jason Wang wrote:> Since we use EWMA to estimate the size of rx buffer. When rx buffer > size is underestimated, it's usual to have a packet with more than one > buffers. Consider this is not a bug, remove the warning and correct > the comment before XDP linearizing. > > Cc: John Fastabend <john.r.fastabend at intel.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/net/virtio_net.c | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 08327e0..1067253 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -552,14 +552,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > struct page *xdp_page; > u32 act; > > - /* No known backend devices should send packets with > - * more than a single buffer when XDP conditions are > - * met. However it is not strictly illegal so the case > - * is handled as an exception and a warning is thrown. > - */ > + /* This happens when rx buffer size is underestimated */ > if (unlikely(num_buf > 1)) { > - bpf_warn_invalid_xdp_buffer();Could you also remove the bpf_warn_invalid_xdp_buffer(), which got added just for this? Thanks.> /* linearize data for XDP */ > xdp_page = xdp_linearize_page(rq, num_buf, > page, offset, &len); >
On 2016?12?24? 01:10, John Fastabend wrote:> On 16-12-23 06:37 AM, Jason Wang wrote: >> Merry Xmas and a Happy New year to all: >> >> This series tries to fixes several issues for virtio-net XDP which >> could be categorized into several parts: >> >> - fix several issues during XDP linearizing >> - allow csumed packet to work for XDP_PASS >> - make EWMA rxbuf size estimation works for XDP >> - forbid XDP when GUEST_UFO is support >> - remove big packet XDP support >> - add XDP support or small buffer >> >> Please see individual patches for details. >> >> Thanks >> >> Jason Wang (9): >> virtio-net: remove the warning before XDP linearizing >> virtio-net: correctly xmit linearized page on XDP_TX >> virtio-net: fix page miscount during XDP linearizing >> virtio-net: correctly handle XDP_PASS for linearized packets >> virtio-net: unbreak csumed packets for XDP_PASS >> virtio-net: make rx buf size estimation works for XDP >> virtio-net: forbid XDP when VIRTIO_NET_F_GUEST_UFO is support >> virtio-net: remove big packet XDP codes >> virtio-net: XDP support for small buffers >> >> drivers/net/virtio_net.c | 172 ++++++++++++++++++++++++++++------------------- >> 1 file changed, 102 insertions(+), 70 deletions(-) >> > Thanks a lot Jason. The last piece that is needed is support to > complete XDP support is to get the adjust_head part correct. I'll > send out a patch in a bit but will need to merge it on top of this > set. > > .JohnYes, glad to see the your patch. Thanks.
John Fastabend
2017-Jan-02 22:43 UTC
[PATCH net 9/9] virtio-net: XDP support for small buffers
On 16-12-23 06:37 AM, Jason Wang wrote:> Commit f600b6905015 ("virtio_net: Add XDP support") leaves the case of > small receive buffer untouched. This will confuse the user who want to > set XDP but use small buffers. Other than forbid XDP in small buffer > mode, let's make it work. XDP then can only work at skb->data since > virtio-net create skbs during refill, this is sub optimal which could > be optimized in the future. > > Cc: John Fastabend <john.r.fastabend at intel.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/net/virtio_net.c | 112 ++++++++++++++++++++++++++++++++++++----------- > 1 file changed, 87 insertions(+), 25 deletions(-) >Hi Jason, I was doing some more testing on this what do you think about doing this so that free_unused_bufs() handles the buffer free with dev_kfree_skb() instead of put_page in small receive mode. Seems more correct to me. diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 783e842..27ff76c 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1898,6 +1898,10 @@ static void free_receive_page_frags(struct virtnet_info *vi) static bool is_xdp_queue(struct virtnet_info *vi, int q) { + /* For small receive mode always use kfree_skb variants */ + if (!vi->mergeable_rx_bufs) + return false; + if (q < (vi->curr_queue_pairs - vi->xdp_queue_pairs)) return false; else if (q < vi->curr_queue_pairs) patch is untested just spotted doing code review. Thanks, John
Reasonably Related Threads
- [PATCH net 1/9] virtio-net: remove the warning before XDP linearizing
- [PATCH net 1/9] virtio-net: remove the warning before XDP linearizing
- [PATCH net 1/9] virtio-net: remove the warning before XDP linearizing
- [PATCH net 0/9] several fixups for virtio-net XDP
- [PATCH net 0/9] several fixups for virtio-net XDP