Re: [Xen-devel] [PATCH net-next v4 2/4] xen-netback: add control protocol implementation

[Wei Liu]

On Fri, May 13, 2016 at 09:37:27AM +0100, Paul Durrant wrote:
> 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: Paul Durrant 
> Cc: Wei Liu 

Acked-by: Wei Liu 

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[Xen-devel] [PATCH net-next v4 2/4] xen-netback: add control protocol implementation

[Paul Durrant]

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: Paul Durrant 
Cc: Wei Liu 
---

v4:
 - Remove calls to init_rcu_head() and destroy_rcu_head()

v3:
 - Remove unintentional label rename

v2:
 - Use RCU list for hash cache
---
 drivers/net/xen-netback/Makefile|   2 +-
 drivers/net/xen-netback/common.h|  46 +
 drivers/net/xen-netback/hash.c  | 384 
 drivers/net/xen-netback/interface.c |  24 +++
 drivers/net/xen-netback/netback.c   |  49 -
 5 files changed, 502 insertions(+), 3 deletions(-)
 create mode 100644 drivers/net/xen-netback/hash.c

diff --git a/drivers/net/xen-netback/Makefile b/drivers/net/xen-netback/Makefile
index e346e81..11e02be 100644
--- a/drivers/net/xen-netback/Makefile
+++ b/drivers/net/xen-netback/Makefile
@@ -1,3 +1,3 @@
 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
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 093a12a..84d6cbd 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -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__ */
diff --git a/drivers/net/xen-netback/hash.c b/drivers/net/xen-netback/hash.c
new file mode 100644
index 000..392e392
--- /dev/null
+++ b/drivers/net/xen-netback/hash.c
@@ -0,0 +1,384 @@
+/*
+ * 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