Allocate zero'd page in block.

Change-Id: Ieb56aa89190d7efd56c357245b24a979ee7ad79a
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/270
Tested-by: Jenkins Server
Reviewed-by: A. Patrick Williams III <iawillia@us.ibm.com>

2 files changed, 12 insertions, 1 deletions

diff --git a/src/include/kernel/spte.H b/src/include/kernel/spte.H
index 92a50c351..6e4832bb6 100644
--- a/src/include/kernel/spte.H
+++ b/src/include/kernel/spte.H
@@ -63,9 +63,11 @@ class ShadowPTE
                 uint32_t track_write:1;
                     /** Has page been written to. */
                 uint32_t dirty:1;
+                    /** Allocate from a zero'd page. */
+                uint32_t allocate_from_zero:1;
 
                     /** Reserved for future use. */
-                uint32_t reserved:7;
+                uint32_t reserved:6;
             } PACKED;
         };
 
diff --git a/src/kernel/block.C b/src/kernel/block.C
index 9426e54ae..19d2962f8 100644
--- a/src/kernel/block.C
+++ b/src/kernel/block.C
@@ -22,6 +22,7 @@
 //  IBM_PROLOG_END
 #include <limits.h>
 #include <assert.h>
+#include <string.h>
 
 #include <sys/msg.h>
 
@@ -93,6 +94,14 @@ bool Block::handlePageFault(task_t* i_task, uint64_t i_addr)
             //Done(waiting for response)
             return true;
         }
+        else if (pte->allocate_from_zero)
+        {
+            void* l_page = PageManager::allocatePage();
+            memset(l_page, '\0', PAGESIZE);
+
+            pte->setPageAddr(reinterpret_cast<uint64_t>(l_page));
+            pte->setPresent(true);
+        }
         else
         {
             return false; //TODO - Swap kernel base block pages for user pages