ibmveth: Enable TCP checksum offload

This patchset enables TCP checksum offload support for IPV4
on ibmveth. This completely eliminates the generation and checking of
the checksum for packets that are completely virtual and never
touch a physical network. A simple TCP_STREAM netperf run on
a virtual network with maximum mtu set yielded a ~30% increase
in throughput. This feature is enabled by default on systems that
support it, but can be disabled with a module option.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 39 insertions, 2 deletions

diff --git a/drivers/net/ibmveth.h b/drivers/net/ibmveth.h
index e05694126f8..3f10f0f4447 100644
--- a/drivers/net/ibmveth.h
+++ b/drivers/net/ibmveth.h
@@ -67,6 +67,21 @@ static inline long h_send_logical_lan(unsigned long unit_address,
 	return rc;
 }
 
+static inline long h_illan_attributes(unsigned long unit_address,
+				      unsigned long reset_mask, unsigned long set_mask,
+				      unsigned long *ret_attributes)
+{
+	long rc;
+	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+
+	rc = plpar_hcall(H_ILLAN_ATTRIBUTES, retbuf, unit_address,
+			 reset_mask, set_mask);
+
+	*ret_attributes = retbuf[0];
+
+	return rc;
+}
+
 #define h_multicast_ctrl(ua, cmd, mac) \
   plpar_hcall_norets(H_MULTICAST_CTRL, ua, cmd, mac)
 
@@ -142,7 +157,9 @@ struct ibmveth_adapter {
 struct ibmveth_buf_desc_fields {
     u32 valid : 1;
     u32 toggle : 1;
-    u32 reserved : 6;
+    u32 reserved : 4;
+    u32 no_csum : 1;
+    u32 csum_good : 1;
     u32 length : 24;
     u32 address;
 };
@@ -152,10 +169,30 @@ union ibmveth_buf_desc {
     struct ibmveth_buf_desc_fields fields;
 };
 
+struct ibmveth_illan_attributes_fields {
+	u32 reserved;
+	u32 reserved2 : 18;
+	u32 csum_offload_padded_pkt_support : 1;
+	u32 reserved3 : 1;
+	u32 trunk_priority : 4;
+	u32 reserved4 : 5;
+	u32 tcp_csum_offload_ipv6 : 1;
+	u32 tcp_csum_offload_ipv4 : 1;
+	u32 active_trunk : 1;
+};
+
+union ibmveth_illan_attributes {
+	u64 desc;
+	struct ibmveth_illan_attributes_fields fields;
+};
+
 struct ibmveth_rx_q_entry {
     u16 toggle : 1;
     u16 valid : 1;
-    u16 reserved : 14;
+    u16 reserved : 4;
+    u16 no_csum : 1;
+    u16 csum_good : 1;
+    u16 reserved2 : 8;
     u16 offset;
     u32 length;
     u64 correlator;