[ovs-dev,01/40] datapath-windows: Use only non executable memory

diff --git a/datapath-windows/ovsext/BufferMgmt.c b/datapath-windows/ovsext/BufferMgmt.c
index 5048ada..6354781 100644
--- a/datapath-windows/ovsext/BufferMgmt.c
+++ b/datapath-windows/ovsext/BufferMgmt.c
@@ -1153,7 +1153,7 @@  FixFragmentHeader(PNET_BUFFER nb, UINT16 fragmentSize,

     mdl = NET_BUFFER_FIRST_MDL(nb);

-    bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(mdl, LowPagePriority);
+    bufferStart = (PUINT8)OvsGetMdlWithLowPrio(mdl);
     if (!bufferStart) {
         return NDIS_STATUS_RESOURCES;
     }
@@ -1211,7 +1211,7 @@  FixSegmentHeader(PNET_BUFFER nb, UINT16 segmentSize, UINT32 seqNumber,

     mdl = NET_BUFFER_FIRST_MDL(nb);

-    bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(mdl, LowPagePriority);
+    bufferStart = (PUINT8)OvsGetMdlWithLowPrio(mdl);
     if (!bufferStart) {
         return NDIS_STATUS_RESOURCES;
     }
@@ -1517,8 +1517,8 @@  OvsAllocateNBLFromBuffer(PVOID context,

     nb = NET_BUFFER_LIST_FIRST_NB(nbl);
     mdl = NET_BUFFER_CURRENT_MDL(nb);
-    data = (PUINT8)MmGetSystemAddressForMdlSafe(mdl, LowPagePriority) +
-                    NET_BUFFER_CURRENT_MDL_OFFSET(nb);
+    data = (PUINT8)OvsGetMdlWithLowPrio(mdl)
+        + NET_BUFFER_CURRENT_MDL_OFFSET(nb);
     if (!data) {
         OvsCompleteNBL(switchContext, nbl, TRUE);
         return NULL;
diff --git a/datapath-windows/ovsext/Datapath.c b/datapath-windows/ovsext/Datapath.c
index 10412a1..21693af 100644
--- a/datapath-windows/ovsext/Datapath.c
+++ b/datapath-windows/ovsext/Datapath.c
@@ -1588,8 +1588,7 @@  MapIrpOutputBuffer(PIRP irp,
     if (irp->MdlAddress == NULL) {
         return STATUS_INVALID_PARAMETER;
     }
-    *buffer = MmGetSystemAddressForMdlSafe(irp->MdlAddress,
-                                           NormalPagePriority);
+    *buffer = OvsGetMdlWithLowPrio(irp->MdlAddress);
     if (*buffer == NULL) {
         return STATUS_INSUFFICIENT_RESOURCES;
     }
diff --git a/datapath-windows/ovsext/Flow.c b/datapath-windows/ovsext/Flow.c
index 852a22f..a7d6317 100644
--- a/datapath-windows/ovsext/Flow.c
+++ b/datapath-windows/ovsext/Flow.c
@@ -1933,7 +1933,7 @@  GetStartAddrNBL(const NET_BUFFER_LIST *_pNB)

     // Ethernet Header is a guaranteed safe access.
     curMdl = (NET_BUFFER_LIST_FIRST_NB(_pNB))->CurrentMdl;
-    curBuffer =  MmGetSystemAddressForMdlSafe(curMdl, LowPagePriority);
+    curBuffer = OvsGetMdlWithLowPrio(curMdl);
     if (!curBuffer) {
         return NULL;
     }
diff --git a/datapath-windows/ovsext/Geneve.c b/datapath-windows/ovsext/Geneve.c
index 43374e2..01b5416 100644
--- a/datapath-windows/ovsext/Geneve.c
+++ b/datapath-windows/ovsext/Geneve.c
@@ -157,8 +157,7 @@  NDIS_STATUS OvsEncapGeneve(POVS_VPORT_ENTRY vport,
         }

         curMdl = NET_BUFFER_CURRENT_MDL(curNb);
-        bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
-                                                           LowPagePriority);
+        bufferStart = (PUINT8)OvsGetMdlWithLowPrio(curMdl);
         if (!bufferStart) {
             status = NDIS_STATUS_RESOURCES;
             goto ret_error;
@@ -286,7 +285,7 @@  NDIS_STATUS OvsDecapGeneve(POVS_SWITCH_CONTEXT switchContext,
     curNbl = *newNbl;
     curNb = NET_BUFFER_LIST_FIRST_NB(curNbl);
     curMdl = NET_BUFFER_CURRENT_MDL(curNb);
-    bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl, LowPagePriority)
+    bufferStart = (PUINT8)OvsGetMdlWithLowPrio(curMdl)
                   + NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
     if (!bufferStart) {
         status = NDIS_STATUS_RESOURCES;
diff --git a/datapath-windows/ovsext/Gre.c b/datapath-windows/ovsext/Gre.c
index f095742..461efe0 100644
--- a/datapath-windows/ovsext/Gre.c
+++ b/datapath-windows/ovsext/Gre.c
@@ -202,8 +202,7 @@  OvsDoEncapGre(POVS_VPORT_ENTRY vport,
         }

         curMdl = NET_BUFFER_CURRENT_MDL(curNb);
-        bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
-                                                           LowPagePriority);
+        bufferStart = (PUINT8)OvsGetMdlWithLowPrio(curMdl);
         if (!bufferStart) {
             status = NDIS_STATUS_RESOURCES;
             goto ret_error;
diff --git a/datapath-windows/ovsext/Offload.c b/datapath-windows/ovsext/Offload.c
index 0905c80..6cc000b 100644
--- a/datapath-windows/ovsext/Offload.c
+++ b/datapath-windows/ovsext/Offload.c
@@ -460,7 +460,7 @@  CalculateChecksumNB(const PNET_BUFFER nb,

     firstMdlLen = MIN(firstMdlLen, packetLen);
     if (offset < firstMdlLen) {
-        src = (PUCHAR) MmGetSystemAddressForMdlSafe(currentMdl, LowPagePriority);
+        src = (PUCHAR)OvsGetMdlWithLowPrio(currentMdl);
         if (!src) {
             return 0;
         }
@@ -485,7 +485,7 @@  CalculateChecksumNB(const PNET_BUFFER nb,
             mdlLen = MIN(mdlLen, packetLen);
         }

-        src = (PUCHAR)MmGetSystemAddressForMdlSafe(currentMdl, LowPagePriority);
+        src = (PUCHAR)OvsGetMdlWithLowPrio(currentMdl);
         if (!src) {
             return 0;
         }
@@ -504,7 +504,7 @@  CalculateChecksumNB(const PNET_BUFFER nb,
         csumDataLen -= csLen;
         currentMdl = NDIS_MDL_LINKAGE(currentMdl);
         if (csumDataLen && currentMdl) {
-            src = MmGetSystemAddressForMdlSafe(currentMdl, LowPagePriority);
+            src = OvsGetMdlWithLowPrio(currentMdl);
             if (!src) {
                 return 0;
             }
@@ -670,8 +670,7 @@  OvsApplySWChecksumOnNB(POVS_PACKET_HDR_INFO layers,
          curNb = curNb->Next) {
         packetLength = NET_BUFFER_DATA_LENGTH(curNb);
         curMdl = NET_BUFFER_CURRENT_MDL(curNb);
-        bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
-                                                           LowPagePriority);
+        bufferStart = (PUINT8)OvsGetMdlWithLowPrio(curMdl);
         if (!bufferStart) {
             return NDIS_STATUS_RESOURCES;
         }
diff --git a/datapath-windows/ovsext/PacketParser.c b/datapath-windows/ovsext/PacketParser.c
index c4a04d0..a52e713 100644
--- a/datapath-windows/ovsext/PacketParser.c
+++ b/datapath-windows/ovsext/PacketParser.c
@@ -38,8 +38,7 @@  OvsGetPacketBytes(const NET_BUFFER_LIST *nbl,

     // Data on current MDL may be offset from start of MDL
     while (destOffset < copyLen && currentMdl) {
-        PUCHAR srcMemory = MmGetSystemAddressForMdlSafe(currentMdl,
-                                                        LowPagePriority);
+        PUCHAR srcMemory = OvsGetMdlWithLowPrio(currentMdl);
         ULONG length = MmGetMdlByteCount(currentMdl);
         if (!srcMemory) {
             status = NDIS_STATUS_RESOURCES;
diff --git a/datapath-windows/ovsext/Stt.c b/datapath-windows/ovsext/Stt.c
index 676cf0c..5490062 100644
--- a/datapath-windows/ovsext/Stt.c
+++ b/datapath-windows/ovsext/Stt.c
@@ -215,8 +215,7 @@  OvsDoEncapStt(POVS_VPORT_ENTRY vport,
             curNb = curNb->Next) {
         curMdl = NET_BUFFER_CURRENT_MDL(curNb);
         innerFrameLen = NET_BUFFER_DATA_LENGTH(curNb);
-        bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
-                                                           LowPagePriority);
+        bufferStart = (PUINT8)OvsGetMdlWithLowPrio(curMdl);
         if (bufferStart == NULL) {
             status = NDIS_STATUS_RESOURCES;
             goto ret_error;
@@ -266,7 +265,7 @@  OvsDoEncapStt(POVS_VPORT_ENTRY vport,
         ASSERT((int) (MmGetMdlByteCount(curMdl) -
                     NET_BUFFER_CURRENT_MDL_OFFSET(curNb)) >= (int) headRoom);

-        buf = (PUINT8) MmGetSystemAddressForMdlSafe(curMdl, LowPagePriority);
+        buf = (PUINT8)OvsGetMdlWithLowPrio(curMdl);
         if (!buf) {
             ASSERT(!"MmGetSystemAddressForMdlSafe failed");
             OVS_LOG_ERROR("MmGetSystemAddressForMdlSafe failed");
@@ -839,8 +838,7 @@  OvsDecapSetOffloads(PNET_BUFFER_LIST *curNbl,
         curNb = NET_BUFFER_LIST_FIRST_NB(*curNbl);
         curMdl = NET_BUFFER_CURRENT_MDL(curNb);

-        buf = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
-            LowPagePriority);
+        buf = (PUINT8)OvsGetMdlWithLowPrio(curMdl);
         if (buf == NULL) {
             return NDIS_STATUS_RESOURCES;
         }
diff --git a/datapath-windows/ovsext/Util.h b/datapath-windows/ovsext/Util.h
index 7aa91ec..cccf9ff 100644
--- a/datapath-windows/ovsext/Util.h
+++ b/datapath-windows/ovsext/Util.h
@@ -146,4 +146,19 @@  UINT32 Rand()
     return seed.LowPart *= 0x8088405 + 1;
 }

+/*
+ *----------------------------------------------------------------------------
+ *  OvsGetMdlWithLowPrio --
+ *    Return the nonpaged system-space virtual address for the given MDL
+ *    `curMdl` using low page priority and no executable memory.
+ *----------------------------------------------------------------------------
+ */
+
+static __inline
+PVOID OvsGetMdlWithLowPrio(PMDL curMdl)

>> Mind renaming this to OvsGetMdlWithLowPriority? Its more readable at the cost of 4 chars.


+{
+return MmGetSystemAddressForMdlSafe(curMdl,
+                                     LowPagePriority | MdlMappingNoExecute);
+}
+
 #endif /* __UTIL_H_ */
diff --git a/datapath-windows/ovsext/Vxlan.c b/datapath-windows/ovsext/Vxlan.c
index f66a7e5..c4315fa 100644
--- a/datapath-windows/ovsext/Vxlan.c
+++ b/datapath-windows/ovsext/Vxlan.c
@@ -244,8 +244,7 @@  OvsDoEncapVxlan(POVS_VPORT_ENTRY vport,
         }

         curMdl = NET_BUFFER_CURRENT_MDL(curNb);
-        bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
-                                                           LowPagePriority);
+        bufferStart = (PUINT8)OvsGetMdlWithLowPrio(curMdl);
         if (!bufferStart) {
             status = NDIS_STATUS_RESOURCES;
             goto ret_error;
@@ -415,8 +414,8 @@  OvsDecapVxlan(POVS_SWITCH_CONTEXT switchContext,
     curNbl = *newNbl;
     curNb = NET_BUFFER_LIST_FIRST_NB(curNbl);
     curMdl = NET_BUFFER_CURRENT_MDL(curNb);
-    bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl, LowPagePriority) +
-                  NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
+    bufferStart = (PUINT8)OvsGetMdlWithLowPrio(curMdl)
+        + NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
     if (!bufferStart) {
         status = NDIS_STATUS_RESOURCES;
         goto dropNbl;