* [PATCH net-next v7 1/2] xen networking: add basic XDP support for xen-netfront
@ 2020-05-04 8:37 Denis Kirjanov
2020-05-04 8:37 ` [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback Denis Kirjanov
2020-05-05 8:33 ` [PATCH net-next v7 1/2] xen networking: add basic XDP support for xen-netfront Jesper Dangaard Brouer
0 siblings, 2 replies; 9+ messages in thread
From: Denis Kirjanov @ 2020-05-04 8:37 UTC (permalink / raw)
To: netdev; +Cc: 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.
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 | 300 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 296 insertions(+), 4 deletions(-)
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 482c6c8..7be8ee6 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 +167,8 @@ struct netfront_info {
struct netfront_stats __percpu *rx_stats;
struct netfront_stats __percpu *tx_stats;
+ bool netback_has_xdp_headroom;
+
atomic_t rx_gso_checksum_fixup;
};
@@ -167,6 +177,9 @@ 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 +278,8 @@ 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 +791,53 @@ 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 +852,9 @@ 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 +890,20 @@ 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 +1071,7 @@ 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 +1089,12 @@ 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 +1342,156 @@ 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);
+ 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 +1503,8 @@ 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
@@ -1419,6 +1652,8 @@ 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 +1989,51 @@ 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_ORDER0, NULL);
+ 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 +2059,14 @@ 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 +2113,8 @@ 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);
rtnl_lock();
if (info->queues)
xennet_destroy_queues(info);
@@ -1959,6 +2249,8 @@ 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] 9+ messages in thread
* [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback
2020-05-04 8:37 [PATCH net-next v7 1/2] xen networking: add basic XDP support for xen-netfront Denis Kirjanov
@ 2020-05-04 8:37 ` Denis Kirjanov
2020-05-05 14:19 ` Paul Durrant
2020-05-05 8:33 ` [PATCH net-next v7 1/2] xen networking: add basic XDP support for xen-netfront Jesper Dangaard Brouer
1 sibling, 1 reply; 9+ messages in thread
From: Denis Kirjanov @ 2020-05-04 8:37 UTC (permalink / raw)
To: netdev; +Cc: 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..7c0450e 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 < 0)
+ 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] 9+ messages in thread
* Re: [PATCH net-next v7 1/2] xen networking: add basic XDP support for xen-netfront
2020-05-04 8:37 [PATCH net-next v7 1/2] xen networking: add basic XDP support for xen-netfront Denis Kirjanov
2020-05-04 8:37 ` [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback Denis Kirjanov
@ 2020-05-05 8:33 ` Jesper Dangaard Brouer
1 sibling, 0 replies; 9+ messages in thread
From: Jesper Dangaard Brouer @ 2020-05-05 8:33 UTC (permalink / raw)
To: Denis Kirjanov; +Cc: brouer, netdev, jgross, wei.liu, paul, ilias.apalodimas
On Mon, 4 May 2020 11:37:53 +0300
Denis Kirjanov <kda@linux-powerpc.org> wrote:
> +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_ORDER0, NULL);
What!?! - You are creating a page_pool, but registering a MEM_TYPE_PAGE_ORDER0.
Have you even tested this? The page_pool in-flight accounting will be
completely off. This should show up when removing the page_pool again.
For driver developers do diagnose and catch stuff like this, we have
some bpftrace scripts that can help troubleshoot, here[1]:
[1] https://github.com/xdp-project/xdp-project/tree/master/areas/mem/bpftrace
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback
2020-05-04 8:37 ` [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback Denis Kirjanov
@ 2020-05-05 14:19 ` Paul Durrant
2020-05-05 15:57 ` Denis Kirjanov
0 siblings, 1 reply; 9+ messages in thread
From: Paul Durrant @ 2020-05-05 14:19 UTC (permalink / raw)
To: 'Denis Kirjanov', netdev; +Cc: jgross, wei.liu, ilias.apalodimas
> -----Original Message-----
> From: Denis Kirjanov <kda@linux-powerpc.org>
> Sent: 04 May 2020 09:38
> To: netdev@vger.kernel.org
> Cc: jgross@suse.com; wei.liu@kernel.org; paul@xen.org; ilias.apalodimas@linaro.org
> Subject: [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback
>
> 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..7c0450e 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 < 0)
xenbus_scanf() returns the number of successfully parsed values so you ought to be checking for != 1 here.
> + 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);
Is the frontend always expected to trigger a re-configure, or could feature-xdp already be enabled prior to connection?
> + 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);
provides_xdp_headroom is bool so the !! ought to be unnecessary.
Paul
> + 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 [flat|nested] 9+ messages in thread
* Re: [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback
2020-05-05 14:19 ` Paul Durrant
@ 2020-05-05 15:57 ` Denis Kirjanov
2020-05-05 16:28 ` Paul Durrant
0 siblings, 1 reply; 9+ messages in thread
From: Denis Kirjanov @ 2020-05-05 15:57 UTC (permalink / raw)
To: paul; +Cc: netdev, jgross, wei.liu, ilias.apalodimas
On 5/5/20, Paul Durrant <xadimgnik@gmail.com> wrote:
>> -----Original Message-----
>> From: Denis Kirjanov <kda@linux-powerpc.org>
>> Sent: 04 May 2020 09:38
>> To: netdev@vger.kernel.org
>> Cc: jgross@suse.com; wei.liu@kernel.org; paul@xen.org;
>> ilias.apalodimas@linaro.org
>> Subject: [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment
>> to xen-netback
>>
>> 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..7c0450e 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 < 0)
>
> xenbus_scanf() returns the number of successfully parsed values so you ought
> to be checking for != 1 here.
right, makes sense.
>
>> + 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);
>
> Is the frontend always expected to trigger a re-configure, or could
> feature-xdp already be enabled prior to connection?
Yes, feature-xdp is set by the frontend when xdp code is loaded.
>
>> + 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);
>
> provides_xdp_headroom is bool so the !! ought to be unnecessary.
Ok, will post the updated version shortly.
Thanks for review!
>
> Paul
>
>> + 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 [flat|nested] 9+ messages in thread
* RE: [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback
2020-05-05 15:57 ` Denis Kirjanov
@ 2020-05-05 16:28 ` Paul Durrant
2020-05-06 17:45 ` Denis Kirjanov
0 siblings, 1 reply; 9+ messages in thread
From: Paul Durrant @ 2020-05-05 16:28 UTC (permalink / raw)
To: 'Denis Kirjanov'; +Cc: netdev, jgross, wei.liu, ilias.apalodimas
> -----Original Message-----
> >> @@ -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);
> >
> > Is the frontend always expected to trigger a re-configure, or could
> > feature-xdp already be enabled prior to connection?
>
> Yes, feature-xdp is set by the frontend when xdp code is loaded.
>
That's still ambiguous... what I'm getting at is whether you also need to read the xdp state when transitioning into Connected as well as Reconfiguring?
Paul
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback
2020-05-05 16:28 ` Paul Durrant
@ 2020-05-06 17:45 ` Denis Kirjanov
2020-05-07 7:18 ` Paul Durrant
0 siblings, 1 reply; 9+ messages in thread
From: Denis Kirjanov @ 2020-05-06 17:45 UTC (permalink / raw)
To: paul; +Cc: netdev, jgross, wei.liu, ilias.apalodimas
On 5/5/20, Paul Durrant <xadimgnik@gmail.com> wrote:
>> -----Original Message-----
>> >> @@ -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);
>> >
>> > Is the frontend always expected to trigger a re-configure, or could
>> > feature-xdp already be enabled prior to connection?
>>
>> Yes, feature-xdp is set by the frontend when xdp code is loaded.
>>
>
> That's still ambiguous... what I'm getting at is whether you also need to
> read the xdp state when transitioning into Connected as well as
> Reconfiguring?
I have to read the state only during the Reconfiguring state since
that's where an XDP program is loaded / unloaded and then we transition
from Reconfigred to Connected
>
> Paul
>
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback
2020-05-06 17:45 ` Denis Kirjanov
@ 2020-05-07 7:18 ` Paul Durrant
2020-05-07 11:30 ` Denis Kirjanov
0 siblings, 1 reply; 9+ messages in thread
From: Paul Durrant @ 2020-05-07 7:18 UTC (permalink / raw)
To: 'Denis Kirjanov'; +Cc: netdev, jgross, wei.liu, ilias.apalodimas
> -----Original Message-----
> From: Denis Kirjanov <kda@linux-powerpc.org>
> Sent: 06 May 2020 18:45
> To: paul@xen.org
> Cc: netdev@vger.kernel.org; jgross@suse.com; wei.liu@kernel.org; ilias.apalodimas@linaro.org
> Subject: Re: [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback
>
> On 5/5/20, Paul Durrant <xadimgnik@gmail.com> wrote:
> >> -----Original Message-----
> >> >> @@ -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);
> >> >
> >> > Is the frontend always expected to trigger a re-configure, or could
> >> > feature-xdp already be enabled prior to connection?
> >>
> >> Yes, feature-xdp is set by the frontend when xdp code is loaded.
> >>
> >
> > That's still ambiguous... what I'm getting at is whether you also need to
> > read the xdp state when transitioning into Connected as well as
> > Reconfiguring?
>
> I have to read the state only during the Reconfiguring state since
> that's where an XDP program is loaded / unloaded and then we transition
> from Reconfigred to Connected
>
Ok, but what about netback re-connection? It is possible that netback can be disconnected, unloaded, reloaded and re-attached to a running frontend. In this case XDP would be active so I still think read_xenbus_frontend_xdp() needs to form part of ring connection (if only in this case).
Paul
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback
2020-05-07 7:18 ` Paul Durrant
@ 2020-05-07 11:30 ` Denis Kirjanov
0 siblings, 0 replies; 9+ messages in thread
From: Denis Kirjanov @ 2020-05-07 11:30 UTC (permalink / raw)
To: paul; +Cc: netdev, jgross, wei.liu, ilias.apalodimas
On 5/7/20, Paul Durrant <xadimgnik@gmail.com> wrote:
>> -----Original Message-----
>> From: Denis Kirjanov <kda@linux-powerpc.org>
>> Sent: 06 May 2020 18:45
>> To: paul@xen.org
>> Cc: netdev@vger.kernel.org; jgross@suse.com; wei.liu@kernel.org;
>> ilias.apalodimas@linaro.org
>> Subject: Re: [PATCH net-next v7 2/2] xen networking: add XDP offset
>> adjustment to xen-netback
>>
>> On 5/5/20, Paul Durrant <xadimgnik@gmail.com> wrote:
>> >> -----Original Message-----
>> >> >> @@ -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);
>> >> >
>> >> > Is the frontend always expected to trigger a re-configure, or could
>> >> > feature-xdp already be enabled prior to connection?
>> >>
>> >> Yes, feature-xdp is set by the frontend when xdp code is loaded.
>> >>
>> >
>> > That's still ambiguous... what I'm getting at is whether you also need
>> > to
>> > read the xdp state when transitioning into Connected as well as
>> > Reconfiguring?
>>
>> I have to read the state only during the Reconfiguring state since
>> that's where an XDP program is loaded / unloaded and then we transition
>> from Reconfigred to Connected
>>
>
> Ok, but what about netback re-connection? It is possible that netback can be
> disconnected, unloaded, reloaded and re-attached to a running frontend. In
> this case XDP would be active so I still think read_xenbus_frontend_xdp()
> needs to form part of ring connection (if only in this case).
I made a change to xdp-netfront to keep the state of XDP
and then just pass the saved state in talk_to_netback()
>
> Paul
>
>
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2020-05-07 11:30 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
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2020-05-04 8:37 [PATCH net-next v7 1/2] xen networking: add basic XDP support for xen-netfront Denis Kirjanov
2020-05-04 8:37 ` [PATCH net-next v7 2/2] xen networking: add XDP offset adjustment to xen-netback Denis Kirjanov
2020-05-05 14:19 ` Paul Durrant
2020-05-05 15:57 ` Denis Kirjanov
2020-05-05 16:28 ` Paul Durrant
2020-05-06 17:45 ` Denis Kirjanov
2020-05-07 7:18 ` Paul Durrant
2020-05-07 11:30 ` Denis Kirjanov
2020-05-05 8:33 ` [PATCH net-next v7 1/2] xen networking: add basic XDP support for xen-netfront Jesper Dangaard Brouer
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