From d1fdcb2607d138f7207eda62a07a04e13c96be83 Mon Sep 17 00:00:00 2001
From: Michael Contreras <michael@inetric.com>
Date: Sun, 2 Dec 2012 20:11:22 -0800
Subject: [PATCH] e1000: Discard packets that are too long if !SBP and !LPE
The e1000_receive function for the e1000 needs to discard packets longer than
1522 bytes if the SBP and LPE flags are disabled. The linux driver assumes
this behavior and allocates memory based on this assumption.
Signed-off-by: Michael Contreras <michael@inetric.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
(cherry picked from commit b0d9ffcd0251161c7c92f94804dcf599dfa3edeb)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
hw/e1000.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/hw/e1000.c b/hw/e1000.c
index e164d79..37d207e 100644
--- a/hw/e1000.c
+++ b/hw/e1000.c
@@ -59,6 +59,9 @@ static int debugflags = DBGBIT(TXERR) | DBGBIT(GENERAL);
#define PNPMMIO_SIZE 0x20000
#define MIN_BUF_SIZE 60 /* Min. octets in an ethernet frame sans FCS */
+/* this is the size past which hardware will drop packets when setting LPE=0 */
+#define MAXIMUM_ETHERNET_VLAN_SIZE 1522
+
/*
* HW models:
* E1000_DEV_ID_82540EM works with Windows and Linux
@@ -693,6 +696,13 @@ e1000_receive(VLANClientState *nc, const uint8_t *buf, size_t size)
size = sizeof(min_buf);
}
+ /* Discard oversized packets if !LPE and !SBP. */
+ if (size > MAXIMUM_ETHERNET_VLAN_SIZE
+ && !(s->mac_reg[RCTL] & E1000_RCTL_LPE)
+ && !(s->mac_reg[RCTL] & E1000_RCTL_SBP)) {
+ return size;
+ }
+
if (!receive_filter(s, buf, size))
return size;