* [PATCH net-next v8 1/3] xen networking: add basic XDP support for xen-netfront
@ 2020-05-07 12:40 Denis Kirjanov
2020-05-07 12:40 ` [PATCH net-next v8 2/3] xen networking: add XDP offset adjustment to xen-netback Denis Kirjanov
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Denis Kirjanov @ 2020-05-07 12:40 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.
v8:
- add PAGE_POOL config dependency
- keep the state of XDP processing in netfront_xdp_enabled
- fixed allocator type in xdp_rxq_info_reg_mem_model()
- minor cleanups in xen-netback
v7:
- use page_pool_dev_alloc_pages() on page allocation
- remove the leftover break statement from netback_changed
v6:
- added the missing SOB line
- fixed subject
v5:
- split netfront/netback changes
- added a sync point between backend/frontend on switching to XDP
- added pagepool API
v4:
- added verbose patch descriprion
- don't expose the XDP headroom offset to the domU guest
- add a modparam to netback to toggle XDP offset
- don't process jumbo frames for now
v3:
- added XDP_TX support (tested with xdping echoserver)
- added XDP_REDIRECT support (tested with modified xdp_redirect_kern)
- moved xdp negotiation to xen-netback
v2:
- avoid data copying while passing to XDP
- tell xen-netback that we need the headroom space
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
drivers/net/xen-netfront.c | 311 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 307 insertions(+), 4 deletions(-)
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 482c6c8..3bba0f0 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;
};
@@ -167,6 +179,9 @@ struct netfront_rx_info {
struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
};
+static int xennet_xdp_xmit(struct net_device *dev, int n,
+ struct xdp_frame **frames, u32 flags);
+
static void skb_entry_set_link(union skb_entry *list, unsigned short id)
{
list->link = id;
@@ -265,8 +280,8 @@ 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;
}
@@ -778,6 +793,53 @@ static int xennet_get_extras(struct netfront_queue *queue,
return err;
}
+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)
+{
+ 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->handle = 0;
+
+ act = bpf_prog_run_xdp(prog, xdp);
+ switch (act) {
+ case XDP_TX:
+ get_page(pdata);
+ xdpf = convert_to_xdp_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);
+ if (unlikely(err))
+ trace_xdp_exception(queue->info->netdev, prog, act);
+ xdp_do_flush();
+ 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)
@@ -792,6 +854,9 @@ static int xennet_get_responses(struct netfront_queue *queue,
int slots = 1;
int err = 0;
unsigned long ret;
+ struct bpf_prog *xdp_prog;
+ struct xdp_buff xdp;
+ u32 verdict;
if (rx->flags & XEN_NETRXF_extra_info) {
err = xennet_get_extras(queue, extras, rp);
@@ -827,9 +892,20 @@ 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 && !(rx->flags & XEN_NETRXF_more_data)) {
+ /* currently only a single page contains data */
+ WARN_ON_ONCE(skb_shinfo(skb)->nr_frags != 1);
+ verdict = xennet_run_xdp(queue,
+ skb_frag_page(&skb_shinfo(skb)->frags[0]),
+ rx, xdp_prog, &xdp);
+ if (verdict != XDP_PASS)
+ err = -EINVAL;
+ }
+ rcu_read_unlock();
next:
+ __skb_queue_tail(list, skb);
if (!(rx->flags & XEN_NETRXF_more_data))
break;
@@ -997,6 +1073,7 @@ static int xennet_poll(struct napi_struct *napi, int budget)
struct sk_buff_head rxq;
struct sk_buff_head errq;
struct sk_buff_head tmpq;
+ struct bpf_prog *xdp_prog;
int err;
spin_lock(&queue->rx_lock);
@@ -1014,6 +1091,12 @@ 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));
+ rcu_read_lock();
+ xdp_prog = rcu_dereference(queue->xdp_prog);
+ if (xdp_prog)
+ rx->offset = XDP_PACKET_HEADROOM;
+ rcu_read_unlock();
+
err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
if (unlikely(err)) {
@@ -1261,6 +1344,157 @@ 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;
+
+ err = xenbus_printf(XBT_NIL, np->xbdev->nodename,
+ "feature-xdp", "%u", xdp);
+ if (err)
+ pr_debug("Error writing feature-xdp\n");
+
+ return err;
+}
+
+static int xennet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
+ struct netlink_ext_ack *extack)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ struct bpf_prog *old_prog;
+ unsigned int i, err;
+ unsigned long int max_mtu = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM;
+
+ 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;
+
+ old_prog = rtnl_dereference(np->queues[0].xdp_prog);
+ if (!old_prog && !prog)
+ return 0;
+
+ 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, XenbusStateReconfiguring);
+
+ err = talk_to_netback_xdp(np, prog ? NETBACK_XDP_HEADROOM_ENABLE:
+ NETBACK_XDP_HEADROOM_DISABLE);
+ if (err)
+ return err;
+
+ /* avoid race with XDP headroom adjustment */
+ wait_event(module_wq,
+ xenbus_read_driver_state(np->xbdev->otherend) ==
+ XenbusStateReconfigured);
+ np->netfront_xdp_enabled = true;
+ xenbus_switch_state(np->xbdev, XenbusStateConnected);
+
+ return 0;
+}
+
+static u32 xennet_xdp_query(struct net_device *dev)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ unsigned int num_queues = dev->real_num_tx_queues;
+ unsigned int i;
+ struct netfront_queue *queue;
+ const struct bpf_prog *xdp_prog;
+
+ 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 int xennet_xdp_xmit_one(struct net_device *dev, struct xdp_frame *xdpf)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
+ struct netfront_queue *queue = NULL;
+ unsigned int num_queues = dev->real_num_tx_queues;
+ unsigned long flags;
+ int notify;
+ struct xen_netif_tx_request *tx;
+
+ queue = &np->queues[smp_processor_id() % num_queues];
+
+ spin_lock_irqsave(&queue->tx_lock, flags);
+
+ tx = 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);
+
+ spin_unlock_irqrestore(&queue->tx_lock, flags);
+ return 0;
+}
+
+static int xennet_xdp_xmit(struct net_device *dev, int n,
+ struct xdp_frame **frames, u32 flags)
+{
+ int drops = 0;
+ int i, err;
+
+ if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
+ return -EINVAL;
+
+ for (i = 0; i < n; i++) {
+ struct xdp_frame *xdpf = frames[i];
+
+ if (!xdpf)
+ continue;
+ err = xennet_xdp_xmit_one(dev, xdpf);
+ if (err) {
+ xdp_return_frame_rx_napi(xdpf);
+ drops++;
+ }
+ }
+
+ return n - drops;
+}
+
static const struct net_device_ops xennet_netdev_ops = {
.ndo_open = xennet_open,
.ndo_stop = xennet_close,
@@ -1272,6 +1506,8 @@ 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 +1567,7 @@ 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 +1656,8 @@ 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 +1993,51 @@ 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 +2063,14 @@ 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 +2117,15 @@ 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);
+ /* 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 +2260,8 @@ 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] 7+ messages in thread
* [PATCH net-next v8 2/3] xen networking: add XDP offset adjustment to xen-netback
2020-05-07 12:40 [PATCH net-next v8 1/3] xen networking: add basic XDP support for xen-netfront Denis Kirjanov
@ 2020-05-07 12:40 ` Denis Kirjanov
2020-05-08 21:07 ` Jakub Kicinski
2020-05-07 12:40 ` [PATCH net-next v8 3/3] net: xen: select PAGE_POOL for xen-netfront Denis Kirjanov
2020-05-08 21:07 ` [PATCH net-next v8 1/3] xen networking: add basic XDP support " Jakub Kicinski
2 siblings, 1 reply; 7+ messages in thread
From: Denis Kirjanov @ 2020-05-07 12:40 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.
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
drivers/net/xen-netback/common.h | 2 ++
drivers/net/xen-netback/netback.c | 7 +++++++
drivers/net/xen-netback/rx.c | 7 ++++++-
drivers/net/xen-netback/xenbus.c | 28 ++++++++++++++++++++++++++++
4 files changed, 43 insertions(+), 1 deletion(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 05847eb..4a148d6 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -280,6 +280,7 @@ struct xenvif {
u8 ip_csum:1;
u8 ipv6_csum:1;
u8 multicast_control:1;
+ u8 xdp_enabled:1;
/* Is this interface disabled? True when backend discovers
* frontend is rogue.
@@ -395,6 +396,7 @@ 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/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..1c0cf8a 100644
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -33,6 +33,11 @@
#include <xen/xen.h>
#include <xen/events.h>
+static inline int xenvif_rx_xdp_offset(struct xenvif *vif)
+{
+ return vif->xdp_enabled ? XDP_PACKET_HEADROOM : 0;
+}
+
static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
{
RING_IDX prod, cons;
@@ -356,7 +361,7 @@ 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 = xenvif_rx_xdp_offset(queue->vif);
unsigned int flags;
do {
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 286054b..9c1b837 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -393,6 +393,20 @@ 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;
+ unsigned int val;
+ int err;
+
+ err = xenbus_scanf(XBT_NIL, dev->otherend,
+ "feature-xdp", "%u", &val);
+ if (err != 1)
+ return;
+ vif->xdp_enabled = val;
+}
+
/**
* Callback received when the frontend's state changes.
*/
@@ -417,6 +431,11 @@ 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;
@@ -1036,6 +1055,15 @@ 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
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH net-next v8 3/3] net: xen: select PAGE_POOL for xen-netfront
2020-05-07 12:40 [PATCH net-next v8 1/3] xen networking: add basic XDP support for xen-netfront Denis Kirjanov
2020-05-07 12:40 ` [PATCH net-next v8 2/3] xen networking: add XDP offset adjustment to xen-netback Denis Kirjanov
@ 2020-05-07 12:40 ` Denis Kirjanov
2020-05-08 21:08 ` Jakub Kicinski
2020-05-08 21:07 ` [PATCH net-next v8 1/3] xen networking: add basic XDP support " Jakub Kicinski
2 siblings, 1 reply; 7+ messages in thread
From: Denis Kirjanov @ 2020-05-07 12:40 UTC (permalink / raw)
To: netdev; +Cc: brouer, jgross, wei.liu, paul, ilias.apalodimas
xen-netfront uses page pool API so select it in Kconfig
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
drivers/net/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 25a8f93..45918ce 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -479,6 +479,7 @@ 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
--
1.8.3.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH net-next v8 1/3] xen networking: add basic XDP support for xen-netfront
2020-05-07 12:40 [PATCH net-next v8 1/3] xen networking: add basic XDP support for xen-netfront Denis Kirjanov
2020-05-07 12:40 ` [PATCH net-next v8 2/3] xen networking: add XDP offset adjustment to xen-netback Denis Kirjanov
2020-05-07 12:40 ` [PATCH net-next v8 3/3] net: xen: select PAGE_POOL for xen-netfront Denis Kirjanov
@ 2020-05-08 21:07 ` Jakub Kicinski
2020-05-09 10:47 ` Denis Kirjanov
2 siblings, 1 reply; 7+ messages in thread
From: Jakub Kicinski @ 2020-05-08 21:07 UTC (permalink / raw)
To: Denis Kirjanov; +Cc: netdev, brouer, jgross, wei.liu, paul, ilias.apalodimas
On Thu, 7 May 2020 15:40:39 +0300 Denis Kirjanov wrote:
> 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.
Please provide a cover letter for the submission.
> @@ -167,6 +179,9 @@ struct netfront_rx_info {
> struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
> };
>
> +static int xennet_xdp_xmit(struct net_device *dev, int n,
> + struct xdp_frame **frames, u32 flags);
Is it possible to put the function here and avoid the forward
declaration?
> static void skb_entry_set_link(union skb_entry *list, unsigned short id)
> {
> list->link = id;
> @@ -265,8 +280,8 @@ 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;
> }
> @@ -778,6 +793,53 @@ static int xennet_get_extras(struct netfront_queue *queue,
> return err;
> }
>
> +u32 xennet_run_xdp(struct netfront_queue *queue, struct page *pdata,
static
> + struct xen_netif_rx_response *rx, struct bpf_prog *prog,
> + struct xdp_buff *xdp)
> +{
> + 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->handle = 0;
No need to clear this.
> + act = bpf_prog_run_xdp(prog, xdp);
> + switch (act) {
> + case XDP_TX:
> + get_page(pdata);
> + xdpf = convert_to_xdp_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);
> + if (unlikely(err))
> + trace_xdp_exception(queue->info->netdev, prog, act);
> + xdp_do_flush();
Can you call flush after the RX loop? (xennet_poll()?) This is supposed
to batch all redirections in the NAPI cycle.
> + 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)
> @@ -792,6 +854,9 @@ static int xennet_get_responses(struct netfront_queue *queue,
> int slots = 1;
> int err = 0;
> unsigned long ret;
> + struct bpf_prog *xdp_prog;
> + struct xdp_buff xdp;
> + u32 verdict;
>
> if (rx->flags & XEN_NETRXF_extra_info) {
> err = xennet_get_extras(queue, extras, rp);
> @@ -827,9 +892,20 @@ 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 && !(rx->flags & XEN_NETRXF_more_data)) {
What is XEN_NETRXF_more_data?
If you have a mis-formatted frame it has to be dropped, nothing can
escape the XDP program and go to the stack.
> + /* currently only a single page contains data */
> + WARN_ON_ONCE(skb_shinfo(skb)->nr_frags != 1);
> + verdict = xennet_run_xdp(queue,
> + skb_frag_page(&skb_shinfo(skb)->frags[0]),
> + rx, xdp_prog, &xdp);
> + if (verdict != XDP_PASS)
> + err = -EINVAL;
> + }
> + rcu_read_unlock();
> next:
> + __skb_queue_tail(list, skb);
> if (!(rx->flags & XEN_NETRXF_more_data))
> break;
>
> +static int xennet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
> + struct netlink_ext_ack *extack)
> +{
> + struct netfront_info *np = netdev_priv(dev);
> + struct bpf_prog *old_prog;
> + unsigned int i, err;
> + unsigned long int max_mtu = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM;
> +
> + 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;
> +
> + old_prog = rtnl_dereference(np->queues[0].xdp_prog);
> + if (!old_prog && !prog)
You don't have to check this, the core will not call drivers any more
if there is no program and request is to disable XDP.
> + return 0;
> +
> + 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);
I'm I reading this right the moment you assign the program the RX
function will start assuming there is a headroom, even if you haven't
reconfigured the backend, yet..
> + if (old_prog)
> + for (i = 0; i < dev->real_num_tx_queues; ++i)
> + bpf_prog_put(old_prog);
> +
> + 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 race with XDP headroom adjustment */
> + wait_event(module_wq,
> + xenbus_read_driver_state(np->xbdev->otherend) ==
> + XenbusStateReconfigured);
> + np->netfront_xdp_enabled = true;
> + xenbus_switch_state(np->xbdev, XenbusStateConnected);
> +
> + return 0;
> +}
> +
> @@ -1754,6 +1993,51 @@ static void xennet_destroy_queues(struct netfront_info *info)
> info->queues = NULL;
> }
>
> +
> +
> +static int xennet_create_page_pool(struct netfront_queue *queue)
Please run checkpatch --strict on your patches.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH net-next v8 2/3] xen networking: add XDP offset adjustment to xen-netback
2020-05-07 12:40 ` [PATCH net-next v8 2/3] xen networking: add XDP offset adjustment to xen-netback Denis Kirjanov
@ 2020-05-08 21:07 ` Jakub Kicinski
0 siblings, 0 replies; 7+ messages in thread
From: Jakub Kicinski @ 2020-05-08 21:07 UTC (permalink / raw)
To: Denis Kirjanov; +Cc: netdev, brouer, jgross, wei.liu, paul, ilias.apalodimas
On Thu, 7 May 2020 15:40:40 +0300 Denis Kirjanov wrote:
> +static inline int xenvif_rx_xdp_offset(struct xenvif *vif)
Please don't use static inlines in C files, compiler will know when to
inline and when not.
> +{
> + return vif->xdp_enabled ? XDP_PACKET_HEADROOM : 0;
> +}
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH net-next v8 3/3] net: xen: select PAGE_POOL for xen-netfront
2020-05-07 12:40 ` [PATCH net-next v8 3/3] net: xen: select PAGE_POOL for xen-netfront Denis Kirjanov
@ 2020-05-08 21:08 ` Jakub Kicinski
0 siblings, 0 replies; 7+ messages in thread
From: Jakub Kicinski @ 2020-05-08 21:08 UTC (permalink / raw)
To: Denis Kirjanov; +Cc: netdev, brouer, jgross, wei.liu, paul, ilias.apalodimas
On Thu, 7 May 2020 15:40:41 +0300 Denis Kirjanov wrote:
> xen-netfront uses page pool API so select it in Kconfig
>
> Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
This needs to be a part of the patch that uses page pool otherwise
build may be broken between the two patches.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH net-next v8 1/3] xen networking: add basic XDP support for xen-netfront
2020-05-08 21:07 ` [PATCH net-next v8 1/3] xen networking: add basic XDP support " Jakub Kicinski
@ 2020-05-09 10:47 ` Denis Kirjanov
0 siblings, 0 replies; 7+ messages in thread
From: Denis Kirjanov @ 2020-05-09 10:47 UTC (permalink / raw)
To: Jakub Kicinski; +Cc: netdev, brouer, jgross, wei.liu, paul, ilias.apalodimas
On 5/9/20, Jakub Kicinski <kuba@kernel.org> wrote:
> On Thu, 7 May 2020 15:40:39 +0300 Denis Kirjanov wrote:
>> 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.
>
> Please provide a cover letter for the submission.
>
>> @@ -167,6 +179,9 @@ struct netfront_rx_info {
>> struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
>> };
>>
>> +static int xennet_xdp_xmit(struct net_device *dev, int n,
>> + struct xdp_frame **frames, u32 flags);
>
> Is it possible to put the function here and avoid the forward
> declaration?
Sure
>
>> static void skb_entry_set_link(union skb_entry *list, unsigned short id)
>> {
>> list->link = id;
>> @@ -265,8 +280,8 @@ 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;
>> }
>> @@ -778,6 +793,53 @@ static int xennet_get_extras(struct netfront_queue
>> *queue,
>> return err;
>> }
>>
>> +u32 xennet_run_xdp(struct netfront_queue *queue, struct page *pdata,
>
> static
>
>> + struct xen_netif_rx_response *rx, struct bpf_prog *prog,
>> + struct xdp_buff *xdp)
>> +{
>> + 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->handle = 0;
>
> No need to clear this.
>
>> + act = bpf_prog_run_xdp(prog, xdp);
>> + switch (act) {
>> + case XDP_TX:
>> + get_page(pdata);
>> + xdpf = convert_to_xdp_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);
>> + if (unlikely(err))
>> + trace_xdp_exception(queue->info->netdev, prog, act);
>> + xdp_do_flush();
>
> Can you call flush after the RX loop? (xennet_poll()?) This is supposed
> to batch all redirections in the NAPI cycle.
Ok, will do
>
>> + 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)
>> @@ -792,6 +854,9 @@ static int xennet_get_responses(struct netfront_queue
>> *queue,
>> int slots = 1;
>> int err = 0;
>> unsigned long ret;
>> + struct bpf_prog *xdp_prog;
>> + struct xdp_buff xdp;
>> + u32 verdict;
>>
>> if (rx->flags & XEN_NETRXF_extra_info) {
>> err = xennet_get_extras(queue, extras, rp);
>> @@ -827,9 +892,20 @@ 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 && !(rx->flags & XEN_NETRXF_more_data)) {
>
> What is XEN_NETRXF_more_data?
>
> If you have a mis-formatted frame it has to be dropped, nothing can
> escape the XDP program and go to the stack.
I see, thanks.
>
>> + /* currently only a single page contains data */
>> + WARN_ON_ONCE(skb_shinfo(skb)->nr_frags != 1);
>> + verdict = xennet_run_xdp(queue,
>> + skb_frag_page(&skb_shinfo(skb)->frags[0]),
>> + rx, xdp_prog, &xdp);
>> + if (verdict != XDP_PASS)
>> + err = -EINVAL;
>> + }
>> + rcu_read_unlock();
>> next:
>> + __skb_queue_tail(list, skb);
>> if (!(rx->flags & XEN_NETRXF_more_data))
>> break;
>>
>
>> +static int xennet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
>> + struct netlink_ext_ack *extack)
>> +{
>> + struct netfront_info *np = netdev_priv(dev);
>> + struct bpf_prog *old_prog;
>> + unsigned int i, err;
>> + unsigned long int max_mtu = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM;
>> +
>> + 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;
>> +
>> + old_prog = rtnl_dereference(np->queues[0].xdp_prog);
>> + if (!old_prog && !prog)
>
> You don't have to check this, the core will not call drivers any more
> if there is no program and request is to disable XDP.
>
>> + return 0;
>> +
>> + 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);
>
> I'm I reading this right the moment you assign the program the RX
> function will start assuming there is a headroom, even if you haven't
> reconfigured the backend, yet..
That's a good catch. Thank you.
>
>> + if (old_prog)
>> + for (i = 0; i < dev->real_num_tx_queues; ++i)
>> + bpf_prog_put(old_prog);
>> +
>> + 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 race with XDP headroom adjustment */
>> + wait_event(module_wq,
>> + xenbus_read_driver_state(np->xbdev->otherend) ==
>> + XenbusStateReconfigured);
>> + np->netfront_xdp_enabled = true;
>> + xenbus_switch_state(np->xbdev, XenbusStateConnected);
>> +
>> + return 0;
>> +}
>> +
>
>> @@ -1754,6 +1993,51 @@ static void xennet_destroy_queues(struct
>> netfront_info *info)
>> info->queues = NULL;
>> }
>>
>> +
>> +
>> +static int xennet_create_page_pool(struct netfront_queue *queue)
>
> Please run checkpatch --strict on your patches.
>
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-05-09 10:47 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-07 12:40 [PATCH net-next v8 1/3] xen networking: add basic XDP support for xen-netfront Denis Kirjanov
2020-05-07 12:40 ` [PATCH net-next v8 2/3] xen networking: add XDP offset adjustment to xen-netback Denis Kirjanov
2020-05-08 21:07 ` Jakub Kicinski
2020-05-07 12:40 ` [PATCH net-next v8 3/3] net: xen: select PAGE_POOL for xen-netfront Denis Kirjanov
2020-05-08 21:08 ` Jakub Kicinski
2020-05-08 21:07 ` [PATCH net-next v8 1/3] xen networking: add basic XDP support " Jakub Kicinski
2020-05-09 10:47 ` Denis Kirjanov
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