From: Paul Durrant <paul.durrant@citrix.com>
Date: Tue, 10 Jan 2017 16:53:08 +0000 (+0000)
Subject: Don't use Packet->Offset when stripping VLAN tags
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=4956eff5936f3e724e3ed974e597b3af4c069bd1;p=people%2Fpauldu%2Fxenvif.git

Don't use Packet->Offset when stripping VLAN tags

The WHQL tests have always been buggy when dealing with packet data that
is offset into the NET_BUFFER MDL chain. Instead, adjust the MappedSystemVa
of the initial MDL.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
---

diff --git a/src/xenvif/receiver.c b/src/xenvif/receiver.c
index 5715dba..701cc86 100644
--- a/src/xenvif/receiver.c
+++ b/src/xenvif/receiver.c
@@ -424,7 +424,11 @@ ReceiverRingProcessTag(
                   Offset);
 
     // Fix up the packet information
-    Packet->Offset += sizeof (ETHERNET_TAG);
+    BaseVa += sizeof (ETHERNET_TAG);
+
+    BaseVa -= Packet->Offset;
+    Packet->Mdl.MappedSystemVa = BaseVa;
+
     Packet->Length -= sizeof (ETHERNET_TAG);
 
     Info->EthernetHeader.Length -= sizeof (ETHERNET_TAG);
@@ -446,10 +450,6 @@ ReceiverRingProcessTag(
 
     Info->Length -= sizeof (ETHERNET_TAG);
 
-    ASSERT(Packet->Mdl.MdlFlags & MDL_MAPPED_TO_SYSTEM_VA);
-    BaseVa = Packet->Mdl.MappedSystemVa;
-    ASSERT(BaseVa != NULL);
-
     BaseVa += Packet->Offset;
 
     EthernetHeader = (PETHERNET_HEADER)(BaseVa + Info->EthernetHeader.Offset);