* [PATCH net-next v14 2/3] xen networking: add basic XDP support for xen-netfront
2020-06-29 13:13 [PATCH net-next v14 0/3] xen networking: add XDP support to xen-netfront Denis Kirjanov
2020-06-29 13:13 ` [PATCH net-next v14 1/3] xen: netif.h: add a new extra type for XDP Denis Kirjanov
@ 2020-06-29 13:13 ` Denis Kirjanov
2020-06-29 13:13 ` [PATCH net-next v14 3/3] xen networking: add XDP offset adjustment to xen-netback Denis Kirjanov
2020-07-01 22:25 ` [PATCH net-next v14 0/3] xen networking: add XDP support to xen-netfront David Miller
3 siblings, 0 replies; 5+ messages in thread
From: Denis Kirjanov @ 2020-06-29 13:13 UTC (permalink / raw)
To: netdev; +Cc: brouer, jgross, wei.liu, paul, ilias.apalodimas
The patch adds a basic XDP processing to xen-netfront driver.
We ran an XDP program for an RX response received from netback
driver. Also we request xen-netback to adjust data offset for
bpf_xdp_adjust_head() header space for custom headers.
synchronization between frontend and backend parts is done
by using xenbus state switching:
Reconfiguring -> Reconfigured- > Connected
UDP packets drop rate using xdp program is around 310 kpps
using ./pktgen_sample04_many_flows.sh and 160 kpps without the patch.
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
---
drivers/net/Kconfig | 1 +
drivers/net/xen-netfront.c | 336 +++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 327 insertions(+), 10 deletions(-)
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 9a49c4c..717abf4 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -495,6 +495,7 @@ config XEN_NETDEV_FRONTEND
tristate "Xen network device frontend driver"
depends on XEN
select XEN_XENBUS_FRONTEND
+ select PAGE_POOL
default y
help
This driver provides support for Xen paravirtual network
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 482c6c8..468f3f6 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -44,6 +44,9 @@
#include <linux/mm.h>
#include <linux/slab.h>
#include <net/ip.h>
+#include <linux/bpf.h>
+#include <net/page_pool.h>
+#include <linux/bpf_trace.h>
#include <xen/xen.h>
#include <xen/xenbus.h>
@@ -102,6 +105,8 @@ struct netfront_queue {
char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
struct netfront_info *info;
+ struct bpf_prog __rcu *xdp_prog;
+
struct napi_struct napi;
/* Split event channels support, tx_* == rx_* when using
@@ -144,6 +149,9 @@ struct netfront_queue {
struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
grant_ref_t gref_rx_head;
grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
+
+ struct page_pool *page_pool;
+ struct xdp_rxq_info xdp_rxq;
};
struct netfront_info {
@@ -159,6 +167,10 @@ struct netfront_info {
struct netfront_stats __percpu *rx_stats;
struct netfront_stats __percpu *tx_stats;
+ /* XDP state */
+ bool netback_has_xdp_headroom;
+ bool netfront_xdp_enabled;
+
atomic_t rx_gso_checksum_fixup;
};
@@ -265,8 +277,8 @@ static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
if (unlikely(!skb))
return NULL;
- page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
- if (!page) {
+ page = page_pool_dev_alloc_pages(queue->page_pool);
+ if (unlikely(!page)) {
kfree_skb(skb);
return NULL;
}
@@ -560,6 +572,66 @@ static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
return queue_idx;
}
+static int xennet_xdp_xmit_one(struct net_device *dev,
+ struct netfront_queue *queue,
+ struct xdp_frame *xdpf)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
+ int notify;
+
+ xennet_make_first_txreq(queue, NULL,
+ virt_to_page(xdpf->data),
+ offset_in_page(xdpf->data),
+ xdpf->len);
+
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
+ if (notify)
+ notify_remote_via_irq(queue->tx_irq);
+
+ u64_stats_update_begin(&tx_stats->syncp);
+ tx_stats->bytes += xdpf->len;
+ tx_stats->packets++;
+ u64_stats_update_end(&tx_stats->syncp);
+
+ xennet_tx_buf_gc(queue);
+
+ return 0;
+}
+
+static int xennet_xdp_xmit(struct net_device *dev, int n,
+ struct xdp_frame **frames, u32 flags)
+{
+ unsigned int num_queues = dev->real_num_tx_queues;
+ struct netfront_info *np = netdev_priv(dev);
+ struct netfront_queue *queue = NULL;
+ unsigned long irq_flags;
+ int drops = 0;
+ int i, err;
+
+ if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
+ return -EINVAL;
+
+ queue = &np->queues[smp_processor_id() % num_queues];
+
+ spin_lock_irqsave(&queue->tx_lock, irq_flags);
+ for (i = 0; i < n; i++) {
+ struct xdp_frame *xdpf = frames[i];
+
+ if (!xdpf)
+ continue;
+ err = xennet_xdp_xmit_one(dev, queue, xdpf);
+ if (err) {
+ xdp_return_frame_rx_napi(xdpf);
+ drops++;
+ }
+ }
+ spin_unlock_irqrestore(&queue->tx_lock, irq_flags);
+
+ return n - drops;
+}
+
+
#define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -778,23 +850,82 @@ static int xennet_get_extras(struct netfront_queue *queue,
return err;
}
+static u32 xennet_run_xdp(struct netfront_queue *queue, struct page *pdata,
+ struct xen_netif_rx_response *rx, struct bpf_prog *prog,
+ struct xdp_buff *xdp, bool *need_xdp_flush)
+{
+ struct xdp_frame *xdpf;
+ u32 len = rx->status;
+ u32 act = XDP_PASS;
+ int err;
+
+ xdp->data_hard_start = page_address(pdata);
+ xdp->data = xdp->data_hard_start + XDP_PACKET_HEADROOM;
+ xdp_set_data_meta_invalid(xdp);
+ xdp->data_end = xdp->data + len;
+ xdp->rxq = &queue->xdp_rxq;
+ xdp->frame_sz = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM;
+
+ act = bpf_prog_run_xdp(prog, xdp);
+ switch (act) {
+ case XDP_TX:
+ get_page(pdata);
+ xdpf = xdp_convert_buff_to_frame(xdp);
+ err = xennet_xdp_xmit(queue->info->netdev, 1, &xdpf, 0);
+ if (unlikely(err < 0))
+ trace_xdp_exception(queue->info->netdev, prog, act);
+ break;
+ case XDP_REDIRECT:
+ get_page(pdata);
+ err = xdp_do_redirect(queue->info->netdev, xdp, prog);
+ *need_xdp_flush = true;
+ if (unlikely(err))
+ trace_xdp_exception(queue->info->netdev, prog, act);
+ break;
+ case XDP_PASS:
+ case XDP_DROP:
+ break;
+
+ case XDP_ABORTED:
+ trace_xdp_exception(queue->info->netdev, prog, act);
+ break;
+
+ default:
+ bpf_warn_invalid_xdp_action(act);
+ }
+
+ return act;
+}
+
static int xennet_get_responses(struct netfront_queue *queue,
struct netfront_rx_info *rinfo, RING_IDX rp,
- struct sk_buff_head *list)
+ struct sk_buff_head *list,
+ bool *need_xdp_flush)
{
struct xen_netif_rx_response *rx = &rinfo->rx;
- struct xen_netif_extra_info *extras = rinfo->extras;
- struct device *dev = &queue->info->netdev->dev;
+ int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD);
RING_IDX cons = queue->rx.rsp_cons;
struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
+ struct xen_netif_extra_info *extras = rinfo->extras;
grant_ref_t ref = xennet_get_rx_ref(queue, cons);
- int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD);
+ struct device *dev = &queue->info->netdev->dev;
+ struct bpf_prog *xdp_prog;
+ struct xdp_buff xdp;
+ unsigned long ret;
int slots = 1;
int err = 0;
- unsigned long ret;
+ u32 verdict;
if (rx->flags & XEN_NETRXF_extra_info) {
err = xennet_get_extras(queue, extras, rp);
+ if (!err) {
+ if (extras[XEN_NETIF_EXTRA_TYPE_XDP - 1].type) {
+ struct xen_netif_extra_info *xdp;
+
+ xdp = &extras[XEN_NETIF_EXTRA_TYPE_XDP - 1];
+ rx->offset = xdp->u.xdp.headroom;
+ }
+ }
cons = queue->rx.rsp_cons;
}
@@ -827,9 +958,24 @@ static int xennet_get_responses(struct netfront_queue *queue,
gnttab_release_grant_reference(&queue->gref_rx_head, ref);
- __skb_queue_tail(list, skb);
-
+ rcu_read_lock();
+ xdp_prog = rcu_dereference(queue->xdp_prog);
+ if (xdp_prog) {
+ if (!(rx->flags & XEN_NETRXF_more_data)) {
+ /* currently only a single page contains data */
+ verdict = xennet_run_xdp(queue,
+ skb_frag_page(&skb_shinfo(skb)->frags[0]),
+ rx, xdp_prog, &xdp, need_xdp_flush);
+ if (verdict != XDP_PASS)
+ err = -EINVAL;
+ } else {
+ /* drop the frame */
+ err = -EINVAL;
+ }
+ }
+ rcu_read_unlock();
next:
+ __skb_queue_tail(list, skb);
if (!(rx->flags & XEN_NETRXF_more_data))
break;
@@ -998,6 +1144,7 @@ static int xennet_poll(struct napi_struct *napi, int budget)
struct sk_buff_head errq;
struct sk_buff_head tmpq;
int err;
+ bool need_xdp_flush = false;
spin_lock(&queue->rx_lock);
@@ -1014,7 +1161,8 @@ static int xennet_poll(struct napi_struct *napi, int budget)
memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
memset(extras, 0, sizeof(rinfo.extras));
- err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
+ err = xennet_get_responses(queue, &rinfo, rp, &tmpq,
+ &need_xdp_flush);
if (unlikely(err)) {
err:
@@ -1060,6 +1208,8 @@ static int xennet_poll(struct napi_struct *napi, int budget)
i = ++queue->rx.rsp_cons;
work_done++;
}
+ if (need_xdp_flush)
+ xdp_do_flush();
__skb_queue_purge(&errq);
@@ -1261,6 +1411,101 @@ static void xennet_poll_controller(struct net_device *dev)
}
#endif
+#define NETBACK_XDP_HEADROOM_DISABLE 0
+#define NETBACK_XDP_HEADROOM_ENABLE 1
+
+static int talk_to_netback_xdp(struct netfront_info *np, int xdp)
+{
+ int err;
+ unsigned short headroom;
+
+ headroom = xdp ? XDP_PACKET_HEADROOM : 0;
+ err = xenbus_printf(XBT_NIL, np->xbdev->nodename,
+ "xdp-headroom", "%hu",
+ headroom);
+ if (err)
+ pr_warn("Error writing xdp-headroom\n");
+
+ return err;
+}
+
+static int xennet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
+ struct netlink_ext_ack *extack)
+{
+ unsigned long max_mtu = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM;
+ struct netfront_info *np = netdev_priv(dev);
+ struct bpf_prog *old_prog;
+ unsigned int i, err;
+
+ if (dev->mtu > max_mtu) {
+ netdev_warn(dev, "XDP requires MTU less than %lu\n", max_mtu);
+ return -EINVAL;
+ }
+
+ if (!np->netback_has_xdp_headroom)
+ return 0;
+
+ xenbus_switch_state(np->xbdev, XenbusStateReconfiguring);
+
+ err = talk_to_netback_xdp(np, prog ? NETBACK_XDP_HEADROOM_ENABLE :
+ NETBACK_XDP_HEADROOM_DISABLE);
+ if (err)
+ return err;
+
+ /* avoid the race with XDP headroom adjustment */
+ wait_event(module_wq,
+ xenbus_read_driver_state(np->xbdev->otherend) ==
+ XenbusStateReconfigured);
+ np->netfront_xdp_enabled = true;
+
+ old_prog = rtnl_dereference(np->queues[0].xdp_prog);
+
+ if (prog)
+ bpf_prog_add(prog, dev->real_num_tx_queues);
+
+ for (i = 0; i < dev->real_num_tx_queues; ++i)
+ rcu_assign_pointer(np->queues[i].xdp_prog, prog);
+
+ if (old_prog)
+ for (i = 0; i < dev->real_num_tx_queues; ++i)
+ bpf_prog_put(old_prog);
+
+ xenbus_switch_state(np->xbdev, XenbusStateConnected);
+
+ return 0;
+}
+
+static u32 xennet_xdp_query(struct net_device *dev)
+{
+ unsigned int num_queues = dev->real_num_tx_queues;
+ struct netfront_info *np = netdev_priv(dev);
+ const struct bpf_prog *xdp_prog;
+ struct netfront_queue *queue;
+ unsigned int i;
+
+ for (i = 0; i < num_queues; ++i) {
+ queue = &np->queues[i];
+ xdp_prog = rtnl_dereference(queue->xdp_prog);
+ if (xdp_prog)
+ return xdp_prog->aux->id;
+ }
+
+ return 0;
+}
+
+static int xennet_xdp(struct net_device *dev, struct netdev_bpf *xdp)
+{
+ switch (xdp->command) {
+ case XDP_SETUP_PROG:
+ return xennet_xdp_set(dev, xdp->prog, xdp->extack);
+ case XDP_QUERY_PROG:
+ xdp->prog_id = xennet_xdp_query(dev);
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
static const struct net_device_ops xennet_netdev_ops = {
.ndo_open = xennet_open,
.ndo_stop = xennet_close,
@@ -1272,6 +1517,8 @@ static void xennet_poll_controller(struct net_device *dev)
.ndo_fix_features = xennet_fix_features,
.ndo_set_features = xennet_set_features,
.ndo_select_queue = xennet_select_queue,
+ .ndo_bpf = xennet_xdp,
+ .ndo_xdp_xmit = xennet_xdp_xmit,
#ifdef CONFIG_NET_POLL_CONTROLLER
.ndo_poll_controller = xennet_poll_controller,
#endif
@@ -1331,6 +1578,7 @@ static struct net_device *xennet_create_dev(struct xenbus_device *dev)
SET_NETDEV_DEV(netdev, &dev->dev);
np->netdev = netdev;
+ np->netfront_xdp_enabled = false;
netif_carrier_off(netdev);
@@ -1419,6 +1667,8 @@ static void xennet_disconnect_backend(struct netfront_info *info)
queue->rx_ring_ref = GRANT_INVALID_REF;
queue->tx.sring = NULL;
queue->rx.sring = NULL;
+
+ page_pool_destroy(queue->page_pool);
}
}
@@ -1754,6 +2004,51 @@ static void xennet_destroy_queues(struct netfront_info *info)
info->queues = NULL;
}
+
+
+static int xennet_create_page_pool(struct netfront_queue *queue)
+{
+ int err;
+ struct page_pool_params pp_params = {
+ .order = 0,
+ .flags = 0,
+ .pool_size = NET_RX_RING_SIZE,
+ .nid = NUMA_NO_NODE,
+ .dev = &queue->info->netdev->dev,
+ .offset = XDP_PACKET_HEADROOM,
+ .max_len = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM,
+ };
+
+ queue->page_pool = page_pool_create(&pp_params);
+ if (IS_ERR(queue->page_pool)) {
+ err = PTR_ERR(queue->page_pool);
+ queue->page_pool = NULL;
+ return err;
+ }
+
+ err = xdp_rxq_info_reg(&queue->xdp_rxq, queue->info->netdev,
+ queue->id);
+ if (err) {
+ netdev_err(queue->info->netdev, "xdp_rxq_info_reg failed\n");
+ goto err_free_pp;
+ }
+
+ err = xdp_rxq_info_reg_mem_model(&queue->xdp_rxq,
+ MEM_TYPE_PAGE_POOL, queue->page_pool);
+ if (err) {
+ netdev_err(queue->info->netdev, "xdp_rxq_info_reg_mem_model failed\n");
+ goto err_unregister_rxq;
+ }
+ return 0;
+
+err_unregister_rxq:
+ xdp_rxq_info_unreg(&queue->xdp_rxq);
+err_free_pp:
+ page_pool_destroy(queue->page_pool);
+ queue->page_pool = NULL;
+ return err;
+}
+
static int xennet_create_queues(struct netfront_info *info,
unsigned int *num_queues)
{
@@ -1779,6 +2074,14 @@ static int xennet_create_queues(struct netfront_info *info,
break;
}
+ /* use page pool recycling instead of buddy allocator */
+ ret = xennet_create_page_pool(queue);
+ if (ret < 0) {
+ dev_err(&info->xbdev->dev, "can't allocate page pool\n");
+ *num_queues = i;
+ return ret;
+ }
+
netif_napi_add(queue->info->netdev, &queue->napi,
xennet_poll, 64);
if (netif_running(info->netdev))
@@ -1825,6 +2128,17 @@ static int talk_to_netback(struct xenbus_device *dev,
goto out_unlocked;
}
+ info->netback_has_xdp_headroom = xenbus_read_unsigned(info->xbdev->otherend,
+ "feature-xdp-headroom", 0);
+ if (info->netback_has_xdp_headroom) {
+ /* set the current xen-netfront xdp state */
+ err = talk_to_netback_xdp(info, info->netfront_xdp_enabled ?
+ NETBACK_XDP_HEADROOM_ENABLE :
+ NETBACK_XDP_HEADROOM_DISABLE);
+ if (err)
+ goto out_unlocked;
+ }
+
rtnl_lock();
if (info->queues)
xennet_destroy_queues(info);
@@ -1959,6 +2273,8 @@ static int xennet_connect(struct net_device *dev)
err = talk_to_netback(np->xbdev, np);
if (err)
return err;
+ if (np->netback_has_xdp_headroom)
+ pr_info("backend supports XDP headroom\n");
/* talk_to_netback() sets the correct number of queues */
num_queues = dev->real_num_tx_queues;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH net-next v14 3/3] xen networking: add XDP offset adjustment to xen-netback
2020-06-29 13:13 [PATCH net-next v14 0/3] xen networking: add XDP support to xen-netfront Denis Kirjanov
2020-06-29 13:13 ` [PATCH net-next v14 1/3] xen: netif.h: add a new extra type for XDP Denis Kirjanov
2020-06-29 13:13 ` [PATCH net-next v14 2/3] xen networking: add basic XDP support for xen-netfront Denis Kirjanov
@ 2020-06-29 13:13 ` Denis Kirjanov
2020-07-01 22:25 ` [PATCH net-next v14 0/3] xen networking: add XDP support to xen-netfront David Miller
3 siblings, 0 replies; 5+ messages in thread
From: Denis Kirjanov @ 2020-06-29 13:13 UTC (permalink / raw)
To: netdev; +Cc: brouer, jgross, wei.liu, paul, ilias.apalodimas
the patch basically adds the offset adjustment and netfront
state reading to make XDP work on netfront side.
Reviewed-by: Paul Durrant <paul@xen.org>
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
---
drivers/net/xen-netback/common.h | 4 ++++
drivers/net/xen-netback/interface.c | 2 ++
drivers/net/xen-netback/netback.c | 7 +++++++
drivers/net/xen-netback/rx.c | 15 ++++++++++++++-
drivers/net/xen-netback/xenbus.c | 34 ++++++++++++++++++++++++++++++++++
5 files changed, 61 insertions(+), 1 deletion(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 05847eb..ae477f7 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -281,6 +281,9 @@ struct xenvif {
u8 ipv6_csum:1;
u8 multicast_control:1;
+ /* headroom requested by xen-netfront */
+ u16 xdp_headroom;
+
/* Is this interface disabled? True when backend discovers
* frontend is rogue.
*/
@@ -395,6 +398,7 @@ static inline pending_ring_idx_t nr_pending_reqs(struct xenvif_queue *queue)
irqreturn_t xenvif_interrupt(int irq, void *dev_id);
extern bool separate_tx_rx_irq;
+extern bool provides_xdp_headroom;
extern unsigned int rx_drain_timeout_msecs;
extern unsigned int rx_stall_timeout_msecs;
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 0c8a02a..8af49728 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -483,6 +483,8 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
vif->queues = NULL;
vif->num_queues = 0;
+ vif->xdp_headroom = 0;
+
spin_lock_init(&vif->lock);
INIT_LIST_HEAD(&vif->fe_mcast_addr);
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 315dfc6..6dfca72 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -96,6 +96,13 @@
module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
MODULE_PARM_DESC(hash_cache_size, "Number of flows in the hash cache");
+/* The module parameter tells that we have to put data
+ * for xen-netfront with the XDP_PACKET_HEADROOM offset
+ * needed for XDP processing
+ */
+bool provides_xdp_headroom = true;
+module_param(provides_xdp_headroom, bool, 0644);
+
static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
u8 status);
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
index ef58870..ac034f6 100644
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -258,6 +258,19 @@ static void xenvif_rx_next_skb(struct xenvif_queue *queue,
pkt->extra_count++;
}
+ if (queue->vif->xdp_headroom) {
+ struct xen_netif_extra_info *extra;
+
+ extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_XDP - 1];
+
+ memset(extra, 0, sizeof(struct xen_netif_extra_info));
+ extra->u.xdp.headroom = queue->vif->xdp_headroom;
+ extra->type = XEN_NETIF_EXTRA_TYPE_XDP;
+ extra->flags = 0;
+
+ pkt->extra_count++;
+ }
+
if (skb->sw_hash) {
struct xen_netif_extra_info *extra;
@@ -356,7 +369,7 @@ static void xenvif_rx_data_slot(struct xenvif_queue *queue,
struct xen_netif_rx_request *req,
struct xen_netif_rx_response *rsp)
{
- unsigned int offset = 0;
+ unsigned int offset = queue->vif->xdp_headroom;
unsigned int flags;
do {
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 286054b..7e62a6e 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -393,6 +393,24 @@ static void set_backend_state(struct backend_info *be,
}
}
+static void read_xenbus_frontend_xdp(struct backend_info *be,
+ struct xenbus_device *dev)
+{
+ struct xenvif *vif = be->vif;
+ u16 headroom;
+ int err;
+
+ err = xenbus_scanf(XBT_NIL, dev->otherend,
+ "xdp-headroom", "%hu", &headroom);
+ if (err != 1) {
+ vif->xdp_headroom = 0;
+ return;
+ }
+ if (headroom > XEN_NETIF_MAX_XDP_HEADROOM)
+ headroom = XEN_NETIF_MAX_XDP_HEADROOM;
+ vif->xdp_headroom = headroom;
+}
+
/**
* Callback received when the frontend's state changes.
*/
@@ -417,6 +435,11 @@ static void frontend_changed(struct xenbus_device *dev,
set_backend_state(be, XenbusStateConnected);
break;
+ case XenbusStateReconfiguring:
+ read_xenbus_frontend_xdp(be, dev);
+ xenbus_switch_state(dev, XenbusStateReconfigured);
+ break;
+
case XenbusStateClosing:
set_backend_state(be, XenbusStateClosing);
break;
@@ -947,6 +970,8 @@ static int read_xenbus_vif_flags(struct backend_info *be)
vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend,
"feature-ipv6-csum-offload", 0);
+ read_xenbus_frontend_xdp(be, dev);
+
return 0;
}
@@ -1036,6 +1061,15 @@ static int netback_probe(struct xenbus_device *dev,
goto abort_transaction;
}
+ /* we can adjust a headroom for netfront XDP processing */
+ err = xenbus_printf(xbt, dev->nodename,
+ "feature-xdp-headroom", "%d",
+ provides_xdp_headroom);
+ if (err) {
+ message = "writing feature-xdp-headroom";
+ goto abort_transaction;
+ }
+
/* We don't support rx-flip path (except old guests who
* don't grok this feature flag).
*/
--
1.8.3.1
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