[PATCH v2 36/41] igb: Implement igb-specific oversize check

[Akihiko Odaki]

igb has a configurable size limit for LPE, and uses different limits
depending on whether the packet is treated as a VLAN packet.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 hw/net/igb_core.c | 36 +++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/hw/net/igb_core.c b/hw/net/igb_core.c
index 54abcf023c..8ff5a2b4bb 100644
--- a/hw/net/igb_core.c
+++ b/hw/net/igb_core.c
@@ -972,16 +972,13 @@ igb_rx_l4_cso_enabled(IGBCore *core)
     return !!(core->mac[RXCSUM] & E1000_RXCSUM_TUOFLD);
 }
 
-static bool
-igb_rx_is_oversized(IGBCore *core, uint16_t qn, size_t size)
+static bool igb_rx_is_oversized(IGBCore *core, const struct eth_header *ehdr,
+                                size_t size, size_t vlan_num,
+                                bool lpe, uint16_t rlpml)
 {
-    uint16_t pool = qn % IGB_NUM_VM_POOLS;
-    bool lpe = !!(core->mac[VMOLR0 + pool] & E1000_VMOLR_LPE);
-    int max_ethernet_lpe_size =
-        core->mac[VMOLR0 + pool] & E1000_VMOLR_RLPML_MASK;
-    int max_ethernet_vlan_size = 1522;
-
-    return size > (lpe ? max_ethernet_lpe_size : max_ethernet_vlan_size);
+    size_t vlan_header_size = sizeof(struct vlan_header) * vlan_num;
+    size_t header_size = sizeof(struct eth_header) + vlan_header_size;
+    return lpe ? size + ETH_FCS_LEN > rlpml : size > header_size + ETH_MTU;
 }
 
 static uint16_t igb_receive_assign(IGBCore *core, const L2Header *l2_header,
@@ -994,6 +991,8 @@ static uint16_t igb_receive_assign(IGBCore *core, const 
L2Header *l2_header,
     uint16_t queues = 0;
     uint16_t oversized = 0;
     size_t vlan_num = 0;
+    bool lpe;
+    uint16_t rlpml;
     int i;
 
     memset(rss_info, 0, sizeof(E1000E_RSSInfo));
@@ -1013,6 +1012,14 @@ static uint16_t igb_receive_assign(IGBCore *core, const 
L2Header *l2_header,
         }
     }
 
+    lpe = !!(core->mac[RCTL] & E1000_RCTL_LPE);
+    rlpml = core->mac[RLPML];
+    if (!(core->mac[RCTL] & E1000_RCTL_SBP) &&
+        igb_rx_is_oversized(core, ehdr, size, vlan_num, lpe, rlpml)) {
+        trace_e1000x_rx_oversized(size);
+        return queues;
+    }
+
     if (vlan_num &&
         !e1000x_rx_vlan_filter(core->mac, l2_header->vlan + vlan_num - 1)) {
         return queues;
@@ -1098,7 +1105,11 @@ static uint16_t igb_receive_assign(IGBCore *core, const 
L2Header *l2_header,
         queues &= core->mac[VFRE];
         if (queues) {
             for (i = 0; i < IGB_NUM_VM_POOLS; i++) {
-                if ((queues & BIT(i)) && igb_rx_is_oversized(core, i, size)) {
+                lpe = !!(core->mac[VMOLR0 + i] & E1000_VMOLR_LPE);
+                rlpml = core->mac[VMOLR0 + i] & E1000_VMOLR_RLPML_MASK;
+                if ((queues & BIT(i)) &&
+                    igb_rx_is_oversized(core, ehdr, size, vlan_num,
+                                        lpe, rlpml)) {
                     oversized |= BIT(i);
                 }
             }
@@ -1654,11 +1665,6 @@ igb_receive_internal(IGBCore *core, const struct iovec 
*iov, int iovcnt,
         iov_to_buf(iov, iovcnt, iov_ofs, &min_buf, sizeof(min_buf.l2_header));
     }
 
-    /* Discard oversized packets if !LPE and !SBP. */
-    if (e1000x_is_oversized(core->mac, size)) {
-        return orig_size;
-    }
-
     net_rx_pkt_set_packet_type(core->rx_pkt,
                                get_eth_packet_type(&min_buf.l2_header.eth));
     net_rx_pkt_set_protocols(core->rx_pkt, iov, iovcnt, iov_ofs);
-- 
2.40.0