[Qemu-devel] [PATCHv2] qemu: e1000 fix TOR math

* [Qemu-devel] [PATCHv2] qemu: e1000 fix TOR math
@ 2010-09-06 11:50 Michael S. Tsirkin
  2010-09-07  9:50 ` [Qemu-devel] " Juan Quintela
  0 siblings, 1 reply; 3+ messages in thread
From: Michael S. Tsirkin @ 2010-09-06 11:50 UTC (permalink / raw)
  Cc: qemu-devel, Juan Quintela

Patch b0b900070c7cb29bbefb732ec00397abe5de6d73 made
TOR valuer incorrect: the spec says it should always
include the CRC field.
No one seems to use this field, but better to stick to spec.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

Changes from v1:
	minor refactoring to avoid += within if statement.

 hw/e1000.c |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/hw/e1000.c b/hw/e1000.c
index 80b78bc..7d7d140 100644
--- a/hw/e1000.c
+++ b/hw/e1000.c
@@ -345,7 +345,7 @@ is_vlan_txd(uint32_t txd_lower)
 
 /* FCS aka Ethernet CRC-32. We don't get it from backends and can't
  * fill it in, just pad descriptor length by 4 bytes unless guest
- * told us to trip it off the packet. */
+ * told us to strip it off the packet. */
 static inline int
 fcs_len(E1000State *s)
 {
@@ -690,9 +690,14 @@ e1000_receive(VLANClientState *nc, const uint8_t *buf, size_t size)
 
     s->mac_reg[GPRC]++;
     s->mac_reg[TPR]++;
-    n = s->mac_reg[TORL];
-    if ((s->mac_reg[TORL] += size) < n)
+    /* TOR - Total Octets Received:
+     * This register includes bytes received in a packet from the <Destination
+     * Address> field through the <CRC> field, inclusively.
+     */
+    n = s->mac_reg[TORL] + size + /* Always include FCS length. */ 4;
+    if (n < s->mac_reg[TORL])
         s->mac_reg[TORH]++;
+    s->mac_reg[TORL] = n;
 
     n = E1000_ICS_RXT0;
     if ((rdt = s->mac_reg[RDT]) < s->mac_reg[RDH])
-- 
1.7.2.rc0.14.g41c1c

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