i40e/i40evf: add PPRS bit to error bits and fix bug in Rx checksum

The driver was not marking packets with bad checksums
correctly, especially IPv6 packets with a bad checksum.
To do this correctly we need a define that may be set by
hardware in rare cases.

Change-ID: I1a997b72b491ded27a78ac3bce1197b2d2611130
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

5 files changed, 115 insertions, 40 deletions

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
index df3917b68c99..b16c25111552 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -119,6 +119,7 @@ static struct i40e_stats i40e_gstrings_stats[] = {
         I40E_PF_STAT("mac_local_faults", stats.mac_local_faults),
         I40E_PF_STAT("mac_remote_faults", stats.mac_remote_faults),
         I40E_PF_STAT("tx_timeout", tx_timeout_count),
+        I40E_PF_STAT("rx_csum_bad", hw_csum_rx_error),
         I40E_PF_STAT("rx_length_errors", stats.rx_length_errors),
         I40E_PF_STAT("link_xon_rx", stats.link_xon_rx),
         I40E_PF_STAT("link_xoff_rx", stats.link_xoff_rx),
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 2622a86de64b..d84f4275f470 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -1193,10 +1193,12 @@ static inline void i40e_rx_checksum(struct i40e_vsi *vsi,
                                     u32 rx_error,
                                     u16 rx_ptype)
 {
+        struct i40e_rx_ptype_decoded decoded = decode_rx_desc_ptype(rx_ptype);
+        bool ipv4 = false, ipv6 = false;
         bool ipv4_tunnel, ipv6_tunnel;
         __wsum rx_udp_csum;
-        __sum16 csum;
         struct iphdr *iph;
+        __sum16 csum;
 
         ipv4_tunnel = (rx_ptype > I40E_RX_PTYPE_GRENAT4_MAC_PAY3) &&
                       (rx_ptype < I40E_RX_PTYPE_GRENAT4_MACVLAN_IPV6_ICMP_PAY4);
@@ -1207,29 +1209,57 @@ static inline void i40e_rx_checksum(struct i40e_vsi *vsi,
         skb->ip_summed = CHECKSUM_NONE;
 
         /* Rx csum enabled and ip headers found? */
-        if (!(vsi->netdev->features & NETIF_F_RXCSUM &&
-              rx_status & (1 << I40E_RX_DESC_STATUS_L3L4P_SHIFT)))
+        if (!(vsi->netdev->features & NETIF_F_RXCSUM))
+                return;
+
+        /* did the hardware decode the packet and checksum? */
+        if (!(rx_status & (1 << I40E_RX_DESC_STATUS_L3L4P_SHIFT)))
+                return;
+
+        /* both known and outer_ip must be set for the below code to work */
+        if (!(decoded.known && decoded.outer_ip))
                 return;
 
+        if (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP &&
+            decoded.outer_ip_ver == I40E_RX_PTYPE_OUTER_IPV4)
+                ipv4 = true;
+        else if (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP &&
+                 decoded.outer_ip_ver == I40E_RX_PTYPE_OUTER_IPV6)
+                ipv6 = true;
+
+        if (ipv4 &&
+            (rx_error & ((1 << I40E_RX_DESC_ERROR_IPE_SHIFT) |
+                         (1 << I40E_RX_DESC_ERROR_EIPE_SHIFT))))
+                goto checksum_fail;
+
         /* likely incorrect csum if alternate IP extension headers found */
-        if (rx_status & (1 << I40E_RX_DESC_STATUS_IPV6EXADD_SHIFT))
+        if (ipv6 &&
+            decoded.inner_prot == I40E_RX_PTYPE_INNER_PROT_TCP &&
+            rx_error & (1 << I40E_RX_DESC_ERROR_L4E_SHIFT) &&
+            rx_status & (1 << I40E_RX_DESC_STATUS_IPV6EXADD_SHIFT))
+                /* don't increment checksum err here, non-fatal err */
                 return;
 
-        /* IP or L4 or outmost IP checksum error */
-        if (rx_error & ((1 << I40E_RX_DESC_ERROR_IPE_SHIFT) |
-                        (1 << I40E_RX_DESC_ERROR_L4E_SHIFT) |
-                        (1 << I40E_RX_DESC_ERROR_EIPE_SHIFT))) {
-                vsi->back->hw_csum_rx_error++;
+        /* there was some L4 error, count error and punt packet to the stack */
+        if (rx_error & (1 << I40E_RX_DESC_ERROR_L4E_SHIFT))
+                goto checksum_fail;
+
+        /* handle packets that were not able to be checksummed due
+         * to arrival speed, in this case the stack can compute
+         * the csum.
+         */
+        if (rx_error & (1 << I40E_RX_DESC_ERROR_PPRS_SHIFT))
                 return;
-        }
 
+        /* If VXLAN traffic has an outer UDPv4 checksum we need to check
+         * it in the driver, hardware does not do it for us.
+         * Since L3L4P bit was set we assume a valid IHL value (>=5)
+         * so the total length of IPv4 header is IHL*4 bytes
+         * The UDP_0 bit *may* bet set if the *inner* header is UDP
+         */
         if (ipv4_tunnel &&
+            (decoded.inner_prot != I40E_RX_PTYPE_INNER_PROT_UDP) &&
             !(rx_status & (1 << I40E_RX_DESC_STATUS_UDP_0_SHIFT))) {
-                /* If VXLAN traffic has an outer UDPv4 checksum we need to check
-                 * it in the driver, hardware does not do it for us.
-                 * Since L3L4P bit was set we assume a valid IHL value (>=5)
-                 * so the total length of IPv4 header is IHL*4 bytes
-                 */
                 skb->transport_header = skb->mac_header +
                                         sizeof(struct ethhdr) +
                                         (ip_hdr(skb)->ihl * 4);
@@ -1246,13 +1276,16 @@ static inline void i40e_rx_checksum(struct i40e_vsi *vsi,
                                 (skb->len - skb_transport_offset(skb)),
                                 IPPROTO_UDP, rx_udp_csum);
 
-                if (udp_hdr(skb)->check != csum) {
-                        vsi->back->hw_csum_rx_error++;
-                        return;
-                }
+                if (udp_hdr(skb)->check != csum)
+                        goto checksum_fail;
         }
 
         skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+        return;
+
+checksum_fail:
+        vsi->back->hw_csum_rx_error++;
 }
 
 /**
@@ -1429,6 +1462,9 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
                 /* ERR_MASK will only have valid bits if EOP set */
                 if (unlikely(rx_error & (1 << I40E_RX_DESC_ERROR_RXE_SHIFT))) {
                         dev_kfree_skb_any(skb);
+                        /* TODO: shouldn't we increment a counter indicating the
+                         * drop?
+                         */
                         goto next_desc;
                 }
 
diff --git a/drivers/net/ethernet/intel/i40e/i40e_type.h b/drivers/net/ethernet/intel/i40e/i40e_type.h
index 6c977d2d48e4..42bfb2aed765 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_type.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_type.h
@@ -541,7 +541,8 @@ enum i40e_rx_desc_error_bits {
         I40E_RX_DESC_ERROR_IPE_SHIFT            = 3,
         I40E_RX_DESC_ERROR_L4E_SHIFT            = 4,
         I40E_RX_DESC_ERROR_EIPE_SHIFT           = 5,
-        I40E_RX_DESC_ERROR_OVERSIZE_SHIFT       = 6
+        I40E_RX_DESC_ERROR_OVERSIZE_SHIFT       = 6,
+        I40E_RX_DESC_ERROR_PPRS_SHIFT           = 7
 };
 
 enum i40e_rx_desc_error_l3l4e_fcoe_masks {
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index ae089df7df19..48ebb6cd69f2 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -728,10 +728,12 @@ static inline void i40e_rx_checksum(struct i40e_vsi *vsi,
                                     u32 rx_error,
                                     u16 rx_ptype)
 {
+        struct i40e_rx_ptype_decoded decoded = decode_rx_desc_ptype(rx_ptype);
+        bool ipv4 = false, ipv6 = false;
         bool ipv4_tunnel, ipv6_tunnel;
         __wsum rx_udp_csum;
-        __sum16 csum;
         struct iphdr *iph;
+        __sum16 csum;
 
         ipv4_tunnel = (rx_ptype > I40E_RX_PTYPE_GRENAT4_MAC_PAY3) &&
                       (rx_ptype < I40E_RX_PTYPE_GRENAT4_MACVLAN_IPV6_ICMP_PAY4);
@@ -742,29 +744,57 @@ static inline void i40e_rx_checksum(struct i40e_vsi *vsi,
         skb->ip_summed = CHECKSUM_NONE;
 
         /* Rx csum enabled and ip headers found? */
-        if (!(vsi->netdev->features & NETIF_F_RXCSUM &&
-              rx_status & (1 << I40E_RX_DESC_STATUS_L3L4P_SHIFT)))
+        if (!(vsi->netdev->features & NETIF_F_RXCSUM))
+                return;
+
+        /* did the hardware decode the packet and checksum? */
+        if (!(rx_status & (1 << I40E_RX_DESC_STATUS_L3L4P_SHIFT)))
+                return;
+
+        /* both known and outer_ip must be set for the below code to work */
+        if (!(decoded.known && decoded.outer_ip))
                 return;
 
+        if (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP &&
+            decoded.outer_ip_ver == I40E_RX_PTYPE_OUTER_IPV4)
+                ipv4 = true;
+        else if (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP &&
+                 decoded.outer_ip_ver == I40E_RX_PTYPE_OUTER_IPV6)
+                ipv6 = true;
+
+        if (ipv4 &&
+            (rx_error & ((1 << I40E_RX_DESC_ERROR_IPE_SHIFT) |
+                         (1 << I40E_RX_DESC_ERROR_EIPE_SHIFT))))
+                goto checksum_fail;
+
         /* likely incorrect csum if alternate IP extension headers found */
-        if (rx_status & (1 << I40E_RX_DESC_STATUS_IPV6EXADD_SHIFT))
+        if (ipv6 &&
+            decoded.inner_prot == I40E_RX_PTYPE_INNER_PROT_TCP &&
+            rx_error & (1 << I40E_RX_DESC_ERROR_L4E_SHIFT) &&
+            rx_status & (1 << I40E_RX_DESC_STATUS_IPV6EXADD_SHIFT))
+                /* don't increment checksum err here, non-fatal err */
                 return;
 
-        /* IP or L4 or outmost IP checksum error */
-        if (rx_error & ((1 << I40E_RX_DESC_ERROR_IPE_SHIFT) |
-                        (1 << I40E_RX_DESC_ERROR_L4E_SHIFT) |
-                        (1 << I40E_RX_DESC_ERROR_EIPE_SHIFT))) {
-                vsi->back->hw_csum_rx_error++;
+        /* there was some L4 error, count error and punt packet to the stack */
+        if (rx_error & (1 << I40E_RX_DESC_ERROR_L4E_SHIFT))
+                goto checksum_fail;
+
+        /* handle packets that were not able to be checksummed due
+         * to arrival speed, in this case the stack can compute
+         * the csum.
+         */
+        if (rx_error & (1 << I40E_RX_DESC_ERROR_PPRS_SHIFT))
                 return;
-        }
 
+        /* If VXLAN traffic has an outer UDPv4 checksum we need to check
+         * it in the driver, hardware does not do it for us.
+         * Since L3L4P bit was set we assume a valid IHL value (>=5)
+         * so the total length of IPv4 header is IHL*4 bytes
+         * The UDP_0 bit *may* bet set if the *inner* header is UDP
+         */
         if (ipv4_tunnel &&
+            (decoded.inner_prot != I40E_RX_PTYPE_INNER_PROT_UDP) &&
             !(rx_status & (1 << I40E_RX_DESC_STATUS_UDP_0_SHIFT))) {
-                /* If VXLAN traffic has an outer UDPv4 checksum we need to check
-                 * it in the driver, hardware does not do it for us.
-                 * Since L3L4P bit was set we assume a valid IHL value (>=5)
-                 * so the total length of IPv4 header is IHL*4 bytes
-                 */
                 skb->transport_header = skb->mac_header +
                                         sizeof(struct ethhdr) +
                                         (ip_hdr(skb)->ihl * 4);
@@ -781,13 +811,16 @@ static inline void i40e_rx_checksum(struct i40e_vsi *vsi,
                                 (skb->len - skb_transport_offset(skb)),
                                 IPPROTO_UDP, rx_udp_csum);
 
-                if (udp_hdr(skb)->check != csum) {
-                        vsi->back->hw_csum_rx_error++;
-                        return;
-                }
+                if (udp_hdr(skb)->check != csum)
+                        goto checksum_fail;
         }
 
         skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+        return;
+
+checksum_fail:
+        vsi->back->hw_csum_rx_error++;
 }
 
 /**
@@ -956,6 +989,9 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
                 /* ERR_MASK will only have valid bits if EOP set */
                 if (unlikely(rx_error & (1 << I40E_RX_DESC_ERROR_RXE_SHIFT))) {
                         dev_kfree_skb_any(skb);
+                        /* TODO: shouldn't we increment a counter indicating the
+                         * drop?
+                         */
                         goto next_desc;
                 }
 
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_type.h b/drivers/net/ethernet/intel/i40evf/i40e_type.h
index e3c9ebbe7ca2..0a7914d11b6a 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_type.h
+++ b/drivers/net/ethernet/intel/i40evf/i40e_type.h
@@ -541,7 +541,8 @@ enum i40e_rx_desc_error_bits {
         I40E_RX_DESC_ERROR_IPE_SHIFT            = 3,
         I40E_RX_DESC_ERROR_L4E_SHIFT            = 4,
         I40E_RX_DESC_ERROR_EIPE_SHIFT           = 5,
-        I40E_RX_DESC_ERROR_OVERSIZE_SHIFT       = 6
+        I40E_RX_DESC_ERROR_OVERSIZE_SHIFT       = 6,
+        I40E_RX_DESC_ERROR_PPRS_SHIFT           = 7
 };
 
 enum i40e_rx_desc_error_l3l4e_fcoe_masks {