[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Xen-devel] [PATCH net-next v1 6/8] xen-netback: add an implementation of toeplitz hashing...



...for receive-side packets.

My recent patch to include/xen/interface/io/netif.h defines a set of
control messages that can be used by a VM frontend driver to configure
toeplitz hashing of receive-side packets and consequent steering of those
packets to particular queues.

This patch introduces an implementation of toeplitz hashing and into
xen-netback and allows it to be configured using the new control messages.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 drivers/net/xen-netback/common.h    |  13 ++++
 drivers/net/xen-netback/interface.c | 149 ++++++++++++++++++++++++++++++++++++
 drivers/net/xen-netback/netback.c   | 128 ++++++++++++++++++++++++++++++-
 3 files changed, 287 insertions(+), 3 deletions(-)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 093a12a..6687702 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -220,6 +220,12 @@ struct xenvif_mcast_addr {
 
 #define XEN_NETBK_MCAST_MAX 64
 
+#define XEN_NETBK_MAX_TOEPLITZ_KEY_SIZE 40
+
+#define XEN_NETBK_MAX_TOEPLITZ_MAPPING_ORDER 7
+#define XEN_NETBK_MAX_TOEPLITZ_MAPPING_SIZE \
+       BIT(XEN_NETBK_MAX_TOEPLITZ_MAPPING_ORDER)
+
 struct xenvif {
        /* Unique identifier for this interface. */
        domid_t          domid;
@@ -251,6 +257,13 @@ struct xenvif {
        unsigned int num_queues; /* active queues, resource allocated */
        unsigned int stalled_queues;
 
+       struct {
+               u32 flags;
+               u8 key[XEN_NETBK_MAX_TOEPLITZ_KEY_SIZE];
+               u32 mapping[XEN_NETBK_MAX_TOEPLITZ_MAPPING_SIZE];
+               unsigned int order;
+       } toeplitz;
+
        struct xenbus_watch credit_watch;
        struct xenbus_watch mcast_ctrl_watch;
 
diff --git a/drivers/net/xen-netback/interface.c 
b/drivers/net/xen-netback/interface.c
index 1850ebb..230afde 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -1,3 +1,4 @@
+
 /*
  * Network-device interface management.
  *
@@ -151,6 +152,153 @@ void xenvif_wake_queue(struct xenvif_queue *queue)
        netif_tx_wake_queue(netdev_get_tx_queue(dev, id));
 }
 
+static u32 toeplitz_hash(const u8 *k, unsigned int klen,
+                        const u8 *d, unsigned int dlen)
+{
+       unsigned int di, ki;
+       u64 prefix = 0;
+       u64 hash = 0;
+
+       /* Pre-load prefix with the first 8 bytes of the key */
+       for (ki = 0; ki < 8; ki++) {
+               prefix <<= 8;
+               prefix |= (ki < klen) ? k[ki] : 0;
+       }
+
+       for (di = 0; di < dlen; di++) {
+               u8 byte = d[di];
+               unsigned int bit;
+
+               for (bit = 0x80; bit != 0; bit >>= 1) {
+                       if (byte & bit)
+                               hash ^= prefix;
+                       prefix <<= 1;
+               }
+
+               /* prefix has now been left-shifted by 8, so OR in
+                * the next byte.
+                */
+               prefix |= (ki < klen) ? k[ki] : 0;
+               ki++;
+       }
+
+       /* The valid part of the hash is in the upper 32 bits. */
+       return hash >> 32;
+}
+
+static void xenvif_set_toeplitz_hash(struct xenvif *vif, struct sk_buff *skb)
+{
+       struct flow_keys flow;
+       u32 hash = 0;
+       enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
+       const u8 *key = vif->toeplitz.key;
+       u32 flags = vif->toeplitz.flags;
+       const unsigned int len = XEN_NETBK_MAX_TOEPLITZ_KEY_SIZE;
+       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_TOEPLITZ_HASH_IPV4_TCP |
+                            XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV4))
+                       break;
+
+               goto done;
+
+       case htons(ETH_P_IPV6):
+               if (flags & (XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV6_TCP |
+                            XEN_NETIF_CTRL_TOEPLITZ_HASH_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_TOEPLITZ_HASH_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 = toeplitz_hash(key, len,
+                                            data, sizeof(data));
+                       type = PKT_HASH_TYPE_L4;
+               } else if (flags & XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV4) {
+                       u8 data[8];
+
+                       memcpy(&data[0], &flow.addrs.v4addrs.src, 4);
+                       memcpy(&data[4], &flow.addrs.v4addrs.dst, 4);
+
+                       hash = toeplitz_hash(key, len,
+                                            data, sizeof(data));
+                       type = PKT_HASH_TYPE_L3;
+               }
+
+               break;
+
+       case htons(ETH_P_IPV6):
+               if (has_tcp_hdr &&
+                   (flags & XEN_NETIF_CTRL_TOEPLITZ_HASH_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 = toeplitz_hash(key, len,
+                                            data, sizeof(data));
+                       type = PKT_HASH_TYPE_L4;
+               } else if (flags & XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV6) {
+                       u8 data[32];
+
+                       memcpy(&data[0], &flow.addrs.v6addrs.src, 16);
+                       memcpy(&data[16], &flow.addrs.v6addrs.dst, 16);
+
+                       hash = toeplitz_hash(key, len,
+                                            data, sizeof(data));
+                       type = PKT_HASH_TYPE_L3;
+               }
+
+               break;
+       }
+
+done:
+       skb_set_hash(skb, hash, type);
+}
+
+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 mask = (1u << vif->toeplitz.order) - 1;
+
+       if (vif->toeplitz.flags == 0)
+               return fallback(dev, skb) % dev->real_num_tx_queues;
+
+       xenvif_set_toeplitz_hash(vif, skb);
+
+       return vif->toeplitz.mapping[skb_get_hash_raw(skb) & mask];
+}
+
 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
        struct xenvif *vif = netdev_priv(dev);
@@ -395,6 +543,7 @@ 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,
diff --git a/drivers/net/xen-netback/netback.c 
b/drivers/net/xen-netback/netback.c
index a1f1a38..41ec7e9 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -2163,6 +2163,89 @@ int xenvif_dealloc_kthread(void *data)
        return 0;
 }
 
+static u32 xenvif_set_toeplitz_flags(struct xenvif *vif, u32 flags)
+{
+       if (flags & ~(XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV4 |
+                     XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV4_TCP |
+                     XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV6 |
+                     XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV6_TCP))
+               return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+
+       vif->toeplitz.flags = flags;
+
+       return XEN_NETIF_CTRL_STATUS_SUCCESS;
+}
+
+static u32 xenvif_set_toeplitz_key(struct xenvif *vif, u32 gref, u32 len)
+{
+       u8 *key = vif->toeplitz.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_TOEPLITZ_KEY_SIZE)
+               return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+
+       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_TOEPLITZ_KEY_SIZE)
+               memset(key + len, 0, XEN_NETBK_MAX_TOEPLITZ_KEY_SIZE - len);
+
+       return XEN_NETIF_CTRL_STATUS_SUCCESS;
+}
+
+static u32 xenvif_set_toeplitz_mapping_order(struct xenvif *vif,
+                                            u32 order)
+{
+       if (order > XEN_NETBK_MAX_TOEPLITZ_MAPPING_ORDER)
+               return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+
+       vif->toeplitz.order = order;
+       memset(vif->toeplitz.mapping, 0, sizeof(u32) << order);
+
+       return XEN_NETIF_CTRL_STATUS_SUCCESS;
+}
+
+static u32 xenvif_set_toeplitz_mapping(struct xenvif *vif, u32 gref,
+                                      u32 len, u32 off)
+{
+       u32 *mapping = &vif->toeplitz.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 > (1u << vif->toeplitz.order)) ||
+           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;
+
+       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;
+}
+
 static void make_ctrl_response(struct xenvif *vif,
                               const struct xen_netif_ctrl_request *req,
                               u32 status, u32 data)
@@ -2191,9 +2274,48 @@ static void push_ctrl_response(struct xenvif *vif)
 static void process_ctrl_request(struct xenvif *vif,
                                 const struct xen_netif_ctrl_request *req)
 {
-       /* There is no support for control requests yet. */
-       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_GET_TOEPLITZ_FLAGS:
+               status = XEN_NETIF_CTRL_STATUS_SUCCESS;
+               data = XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV4 |
+                      XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV4_TCP |
+                      XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV6 |
+                      XEN_NETIF_CTRL_TOEPLITZ_HASH_IPV6_TCP;
+               break;
+
+       case XEN_NETIF_CTRL_TYPE_SET_TOEPLITZ_FLAGS:
+               status = xenvif_set_toeplitz_flags(vif, req->data[0]);
+               break;
+
+       case XEN_NETIF_CTRL_TYPE_SET_TOEPLITZ_KEY:
+               status = xenvif_set_toeplitz_key(vif, req->data[0],
+                                                req->data[1]);
+               break;
+
+       case XEN_NETIF_CTRL_TYPE_GET_TOEPLITZ_MAPPING_ORDER:
+               status = XEN_NETIF_CTRL_STATUS_SUCCESS;
+               data = XEN_NETBK_MAX_TOEPLITZ_MAPPING_ORDER;
+               break;
+
+       case XEN_NETIF_CTRL_TYPE_SET_TOEPLITZ_MAPPING_ORDER:
+               status = xenvif_set_toeplitz_mapping_order(vif,
+                                                          req->data[0]);
+               break;
+
+       case XEN_NETIF_CTRL_TYPE_SET_TOEPLITZ_MAPPING:
+               status = xenvif_set_toeplitz_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);
 }
 
-- 
2.1.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.