[Xen-changelog] [qemu-upstream-unstable] e1000: Discard packets that are too long if !SBP and !LPE

[patchbot@xxxxxxx]

commit b0d9ffcd0251161c7c92f94804dcf599dfa3edeb
Author: Michael Contreras <michael@xxxxxxxxxxx>
Date:   Sun Dec 2 20:11:22 2012 -0800

    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@xxxxxxxxxxx>
    Signed-off-by: Anthony Liguori <aliguori@xxxxxxxxxx>
---
 hw/e1000.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/hw/e1000.c b/hw/e1000.c
index cb7e7e8..5537ad2 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
@@ -805,6 +808,13 @@ e1000_receive(NetClientState *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;
 
--
generated by git-patchbot for /home/xen/git/qemu-upstream-unstable.git

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