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Commit 40d8abde authored by Paul Durrant's avatar Paul Durrant Committed by David S. Miller
Browse files

xen-netback: add control protocol implementation 



My recent patch to include/xen/interface/io/netif.h defines a new shared
ring (in addition to the rx and tx rings) for passing control messages
from a VM frontend driver to a backend driver.

A previous patch added the necessary boilerplate for mapping the control
ring from the frontend, should it be created. This patch adds
implementations for each of the defined protocol messages.

Signed-off-by: default avatarPaul Durrant <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Acked-by: default avatarWei Liu <wei.liu2@citrix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4e15ee2c

drivers/net/xen-netback/Makefile

+1 −1
Original line number Diff line number Diff line 
obj-$(CONFIG_XEN_NETDEV_BACKEND) := xen-netback.o



xen-netback-y := netback.o xenbus.o interface.o
 
xen-netback-y := netback.o xenbus.o interface.o hash.o

drivers/net/xen-netback/common.h

+46 −0
Original line number Diff line number Diff line
@@ -220,6 +220,35 @@ struct xenvif_mcast_addr { 


#define XEN_NETBK_MCAST_MAX 64



#define XEN_NETBK_MAX_HASH_KEY_SIZE 40

#define XEN_NETBK_MAX_HASH_MAPPING_SIZE 128

#define XEN_NETBK_HASH_TAG_SIZE 40



struct xenvif_hash_cache_entry {

	struct list_head link;

	struct rcu_head rcu;

	u8 tag[XEN_NETBK_HASH_TAG_SIZE];

	unsigned int len;

	u32 val;

	int seq;

};



struct xenvif_hash_cache {

	spinlock_t lock;

	struct list_head list;

	unsigned int count;

	atomic_t seq;

};



struct xenvif_hash {

	unsigned int alg;

	u32 flags;

	u8 key[XEN_NETBK_MAX_HASH_KEY_SIZE];

	u32 mapping[XEN_NETBK_MAX_HASH_MAPPING_SIZE];

	unsigned int size;

	struct xenvif_hash_cache cache;

};



struct xenvif {

	/* Unique identifier for this interface. */

	domid_t          domid;
@@ -251,6 +280,8 @@ struct xenvif { 
	unsigned int num_queues; /* active queues, resource allocated */

	unsigned int stalled_queues;



	struct xenvif_hash hash;



	struct xenbus_watch credit_watch;

	struct xenbus_watch mcast_ctrl_watch;
@@ -353,6 +384,7 @@ extern bool separate_tx_rx_irq; 
extern unsigned int rx_drain_timeout_msecs;

extern unsigned int rx_stall_timeout_msecs;

extern unsigned int xenvif_max_queues;

extern unsigned int xenvif_hash_cache_size;



#ifdef CONFIG_DEBUG_FS

extern struct dentry *xen_netback_dbg_root;
@@ -366,4 +398,18 @@ void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue); 
bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr);

void xenvif_mcast_addr_list_free(struct xenvif *vif);



/* Hash */

void xenvif_init_hash(struct xenvif *vif);

void xenvif_deinit_hash(struct xenvif *vif);



u32 xenvif_set_hash_alg(struct xenvif *vif, u32 alg);

u32 xenvif_get_hash_flags(struct xenvif *vif, u32 *flags);

u32 xenvif_set_hash_flags(struct xenvif *vif, u32 flags);

u32 xenvif_set_hash_key(struct xenvif *vif, u32 gref, u32 len);

u32 xenvif_set_hash_mapping_size(struct xenvif *vif, u32 size);

u32 xenvif_set_hash_mapping(struct xenvif *vif, u32 gref, u32 len,

			    u32 off);



void xenvif_set_skb_hash(struct xenvif *vif, struct sk_buff *skb);



#endif /* __XEN_NETBACK__COMMON_H__ */

drivers/net/xen-netback/hash.c

0 → 100644
+384 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2016 Citrix Systems Inc.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License version 2

 * as published by the Free Softare Foundation; or, when distributed

 * separately from the Linux kernel or incorporated into other

 * software packages, subject to the following license:

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this source file (the "Software"), to deal in the Software without

 * restriction, including without limitation the rights to use, copy, modify,

 * merge, publish, distribute, sublicense, and/or sell copies of the Software,

 * and to permit persons to whom the Software is furnished to do so, subject to

 * the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */



#define XEN_NETIF_DEFINE_TOEPLITZ



#include "common.h"

#include <linux/vmalloc.h>

#include <linux/rculist.h>



static void xenvif_del_hash(struct rcu_head *rcu)

{

	struct xenvif_hash_cache_entry *entry;



	entry = container_of(rcu, struct xenvif_hash_cache_entry, rcu);



	kfree(entry);

}



static void xenvif_add_hash(struct xenvif *vif, const u8 *tag,

			    unsigned int len, u32 val)

{

	struct xenvif_hash_cache_entry *new, *entry, *oldest;

	unsigned long flags;

	bool found;



	new = kmalloc(sizeof(*entry), GFP_KERNEL);

	if (!new)

		return;



	memcpy(new->tag, tag, len);

	new->len = len;

	new->val = val;



	spin_lock_irqsave(&vif->hash.cache.lock, flags);



	found = false;

	oldest = NULL;

	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {

		/* Make sure we don't add duplicate entries */

		if (entry->len == len &&

		    memcmp(entry->tag, tag, len) == 0)

			found = true;

		if (!oldest || entry->seq < oldest->seq)

			oldest = entry;

	}



	if (!found) {

		new->seq = atomic_inc_return(&vif->hash.cache.seq);

		list_add_rcu(&new->link, &vif->hash.cache.list);



		if (++vif->hash.cache.count > xenvif_hash_cache_size) {

			list_del_rcu(&oldest->link);

			vif->hash.cache.count--;

			call_rcu(&oldest->rcu, xenvif_del_hash);

		}

	}



	spin_unlock_irqrestore(&vif->hash.cache.lock, flags);



	if (found)

		kfree(new);

}



static u32 xenvif_new_hash(struct xenvif *vif, const u8 *data,

			   unsigned int len)

{

	u32 val;



	val = xen_netif_toeplitz_hash(vif->hash.key,

				      sizeof(vif->hash.key),

				      data, len);



	if (xenvif_hash_cache_size != 0)

		xenvif_add_hash(vif, data, len, val);



	return val;

}



static void xenvif_flush_hash(struct xenvif *vif)

{

	struct xenvif_hash_cache_entry *entry;

	unsigned long flags;



	if (xenvif_hash_cache_size == 0)

		return;



	spin_lock_irqsave(&vif->hash.cache.lock, flags);



	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {

		list_del_rcu(&entry->link);

		vif->hash.cache.count--;

		call_rcu(&entry->rcu, xenvif_del_hash);

	}



	spin_unlock_irqrestore(&vif->hash.cache.lock, flags);

}



static u32 xenvif_find_hash(struct xenvif *vif, const u8 *data,

			    unsigned int len)

{

	struct xenvif_hash_cache_entry *entry;

	u32 val;

	bool found;



	if (len >= XEN_NETBK_HASH_TAG_SIZE)

		return 0;



	if (xenvif_hash_cache_size == 0)

		return xenvif_new_hash(vif, data, len);



	rcu_read_lock();



	found = false;



	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {

		if (entry->len == len &&

		    memcmp(entry->tag, data, len) == 0) {

			val = entry->val;

			entry->seq = atomic_inc_return(&vif->hash.cache.seq);

			found = true;

			break;

		}

	}



	rcu_read_unlock();



	if (!found)

		val = xenvif_new_hash(vif, data, len);



	return val;

}



void xenvif_set_skb_hash(struct xenvif *vif, struct sk_buff *skb)

{

	struct flow_keys flow;

	u32 hash = 0;

	enum pkt_hash_types type = PKT_HASH_TYPE_NONE;

	u32 flags = vif->hash.flags;

	bool has_tcp_hdr;



	/* Quick rejection test: If the network protocol doesn't

	 * correspond to any enabled hash type then there's no point

	 * in parsing the packet header.

	 */

	switch (skb->protocol) {

	case htons(ETH_P_IP):

		if (flags & (XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |

			     XEN_NETIF_CTRL_HASH_TYPE_IPV4))

			break;



		goto done;



	case htons(ETH_P_IPV6):

		if (flags & (XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP |

			     XEN_NETIF_CTRL_HASH_TYPE_IPV6))

			break;



		goto done;



	default:

		goto done;

	}



	memset(&flow, 0, sizeof(flow));

	if (!skb_flow_dissect_flow_keys(skb, &flow, 0))

		goto done;



	has_tcp_hdr = (flow.basic.ip_proto == IPPROTO_TCP) &&

		      !(flow.control.flags & FLOW_DIS_IS_FRAGMENT);



	switch (skb->protocol) {

	case htons(ETH_P_IP):

		if (has_tcp_hdr &&

		    (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP)) {

			u8 data[12];



			memcpy(&data[0], &flow.addrs.v4addrs.src, 4);

			memcpy(&data[4], &flow.addrs.v4addrs.dst, 4);

			memcpy(&data[8], &flow.ports.src, 2);

			memcpy(&data[10], &flow.ports.dst, 2);



			hash = xenvif_find_hash(vif, data, sizeof(data));

			type = PKT_HASH_TYPE_L4;

		} else if (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4) {

			u8 data[8];



			memcpy(&data[0], &flow.addrs.v4addrs.src, 4);

			memcpy(&data[4], &flow.addrs.v4addrs.dst, 4);



			hash = xenvif_find_hash(vif, data, sizeof(data));

			type = PKT_HASH_TYPE_L3;

		}



		break;



	case htons(ETH_P_IPV6):

		if (has_tcp_hdr &&

		    (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP)) {

			u8 data[36];



			memcpy(&data[0], &flow.addrs.v6addrs.src, 16);

			memcpy(&data[16], &flow.addrs.v6addrs.dst, 16);

			memcpy(&data[32], &flow.ports.src, 2);

			memcpy(&data[34], &flow.ports.dst, 2);



			hash = xenvif_find_hash(vif, data, sizeof(data));

			type = PKT_HASH_TYPE_L4;

		} else if (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6) {

			u8 data[32];



			memcpy(&data[0], &flow.addrs.v6addrs.src, 16);

			memcpy(&data[16], &flow.addrs.v6addrs.dst, 16);



			hash = xenvif_find_hash(vif, data, sizeof(data));

			type = PKT_HASH_TYPE_L3;

		}



		break;

	}



done:

	if (type == PKT_HASH_TYPE_NONE)

		skb_clear_hash(skb);

	else

		__skb_set_sw_hash(skb, hash, type == PKT_HASH_TYPE_L4);

}



u32 xenvif_set_hash_alg(struct xenvif *vif, u32 alg)

{

	switch (alg) {

	case XEN_NETIF_CTRL_HASH_ALGORITHM_NONE:

	case XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ:

		break;



	default:

		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;

	}



	vif->hash.alg = alg;



	return XEN_NETIF_CTRL_STATUS_SUCCESS;

}



u32 xenvif_get_hash_flags(struct xenvif *vif, u32 *flags)

{

	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)

		return XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;



	*flags = XEN_NETIF_CTRL_HASH_TYPE_IPV4 |

		 XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |

		 XEN_NETIF_CTRL_HASH_TYPE_IPV6 |

		 XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP;



	return XEN_NETIF_CTRL_STATUS_SUCCESS;

}



u32 xenvif_set_hash_flags(struct xenvif *vif, u32 flags)

{

	if (flags & ~(XEN_NETIF_CTRL_HASH_TYPE_IPV4 |

		      XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |

		      XEN_NETIF_CTRL_HASH_TYPE_IPV6 |

		      XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP))

		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;



	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)

		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;



	vif->hash.flags = flags;



	return XEN_NETIF_CTRL_STATUS_SUCCESS;

}



u32 xenvif_set_hash_key(struct xenvif *vif, u32 gref, u32 len)

{

	u8 *key = vif->hash.key;

	struct gnttab_copy copy_op = {

		.source.u.ref = gref,

		.source.domid = vif->domid,

		.dest.u.gmfn = virt_to_gfn(key),

		.dest.domid = DOMID_SELF,

		.dest.offset = xen_offset_in_page(key),

		.len = len,

		.flags = GNTCOPY_source_gref

	};



	if (len > XEN_NETBK_MAX_HASH_KEY_SIZE)

		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;



	if (len != 0) {

		gnttab_batch_copy(&copy_op, 1);



		if (copy_op.status != GNTST_okay)

			return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;

	}



	/* Clear any remaining key octets */

	if (len < XEN_NETBK_MAX_HASH_KEY_SIZE)

		memset(key + len, 0, XEN_NETBK_MAX_HASH_KEY_SIZE - len);



	xenvif_flush_hash(vif);



	return XEN_NETIF_CTRL_STATUS_SUCCESS;

}



u32 xenvif_set_hash_mapping_size(struct xenvif *vif, u32 size)

{

	if (size > XEN_NETBK_MAX_HASH_MAPPING_SIZE)

		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;



	vif->hash.size = size;

	memset(vif->hash.mapping, 0, sizeof(u32) * size);



	return XEN_NETIF_CTRL_STATUS_SUCCESS;

}



u32 xenvif_set_hash_mapping(struct xenvif *vif, u32 gref, u32 len,

			    u32 off)

{

	u32 *mapping = &vif->hash.mapping[off];

	struct gnttab_copy copy_op = {

		.source.u.ref = gref,

		.source.domid = vif->domid,

		.dest.u.gmfn = virt_to_gfn(mapping),

		.dest.domid = DOMID_SELF,

		.dest.offset = xen_offset_in_page(mapping),

		.len = len * sizeof(u32),

		.flags = GNTCOPY_source_gref

	};



	if ((off + len > vif->hash.size) || copy_op.len > XEN_PAGE_SIZE)

		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;



	while (len-- != 0)

		if (mapping[off++] >= vif->num_queues)

			return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;



	if (len != 0) {

		gnttab_batch_copy(&copy_op, 1);



		if (copy_op.status != GNTST_okay)

			return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;

	}



	return XEN_NETIF_CTRL_STATUS_SUCCESS;

}



void xenvif_init_hash(struct xenvif *vif)

{

	if (xenvif_hash_cache_size == 0)

		return;



	spin_lock_init(&vif->hash.cache.lock);

	INIT_LIST_HEAD(&vif->hash.cache.list);

}



void xenvif_deinit_hash(struct xenvif *vif)

{

	xenvif_flush_hash(vif);

}

drivers/net/xen-netback/interface.c

+24 −0
Original line number Diff line number Diff line
@@ -151,6 +151,24 @@ void xenvif_wake_queue(struct xenvif_queue *queue) 
	netif_tx_wake_queue(netdev_get_tx_queue(dev, id));

}



static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,

			       void *accel_priv,

			       select_queue_fallback_t fallback)

{

	struct xenvif *vif = netdev_priv(dev);

	unsigned int size = vif->hash.size;



	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)

		return fallback(dev, skb) % dev->real_num_tx_queues;



	xenvif_set_skb_hash(vif, skb);



	if (size == 0)

		return skb_get_hash_raw(skb) % dev->real_num_tx_queues;



	return vif->hash.mapping[skb_get_hash_raw(skb) % size];

}



static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)

{

	struct xenvif *vif = netdev_priv(dev);
@@ -395,6 +413,7 @@ static const struct ethtool_ops xenvif_ethtool_ops = { 
};



static const struct net_device_ops xenvif_netdev_ops = {

	.ndo_select_queue = xenvif_select_queue,

	.ndo_start_xmit	= xenvif_start_xmit,

	.ndo_get_stats	= xenvif_get_stats,

	.ndo_open	= xenvif_open,
@@ -563,6 +582,8 @@ int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref, 


	vif->ctrl_irq = err;



	xenvif_init_hash(vif);



	task = kthread_create(xenvif_ctrl_kthread, (void *)vif,

			      "%s-control", dev->name);

	if (IS_ERR(task)) {
@@ -579,6 +600,7 @@ int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref, 
	return 0;



err_deinit:

	xenvif_deinit_hash(vif);

	unbind_from_irqhandler(vif->ctrl_irq, vif);

	vif->ctrl_irq = 0;
@@ -749,6 +771,8 @@ void xenvif_disconnect_ctrl(struct xenvif *vif) 
		vif->ctrl_task = NULL;

	}



	xenvif_deinit_hash(vif);



	if (vif->ctrl_irq) {

		unbind_from_irqhandler(vif->ctrl_irq, vif);

		vif->ctrl_irq = 0;

drivers/net/xen-netback/netback.c

+47 −2
Original line number Diff line number Diff line
@@ -89,6 +89,11 @@ module_param(fatal_skb_slots, uint, 0444); 
 */

#define XEN_NETBACK_TX_COPY_LEN 128



/* This is the maximum number of flows in the hash cache. */

#define XENVIF_HASH_CACHE_SIZE_DEFAULT 64

unsigned int xenvif_hash_cache_size = XENVIF_HASH_CACHE_SIZE_DEFAULT;

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");



static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,

			       u8 status);
@@ -2192,8 +2197,48 @@ static void push_ctrl_response(struct xenvif *vif) 
static void process_ctrl_request(struct xenvif *vif,

				 const struct xen_netif_ctrl_request *req)

{

	make_ctrl_response(vif, req, XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED,

			   0);

	u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;

	u32 data = 0;



	switch (req->type) {

	case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:

		status = xenvif_set_hash_alg(vif, req->data[0]);

		break;



	case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:

		status = xenvif_get_hash_flags(vif, &data);

		break;



	case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:

		status = xenvif_set_hash_flags(vif, req->data[0]);

		break;



	case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:

		status = xenvif_set_hash_key(vif, req->data[0],

					     req->data[1]);

		break;



	case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:

		status = XEN_NETIF_CTRL_STATUS_SUCCESS;

		data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;

		break;



	case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:

		status = xenvif_set_hash_mapping_size(vif,

						      req->data[0]);

		break;



	case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:

		status = xenvif_set_hash_mapping(vif, req->data[0],

						 req->data[1],

						 req->data[2]);

		break;



	default:

		break;

	}



	make_ctrl_response(vif, req, status, data);

	push_ctrl_response(vif);

}