From 471f09f1a9bcc46fc385fa8aca776cb682075c0b Mon Sep 17 00:00:00 2001
From: Patrick Williams <iawillia@us.ibm.com>
Date: Fri, 8 Jul 2011 19:33:40 -0500
Subject: VMM Improvements.

    - Segment Manager
    - Base / Device Segments
    - Block for Base image.

Change-Id: Ic0c058e5c5b210ec1c48d30f6ed9f9837d74a3c8
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/193
Tested-by: Jenkins Server
Reviewed-by: MATTHEW S. BARTH <msbarth@us.ibm.com>
---
 src/include/kernel/spte.H | 87 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 src/include/kernel/spte.H

(limited to 'src/include/kernel/spte.H')

diff --git a/src/include/kernel/spte.H b/src/include/kernel/spte.H
new file mode 100644
index 000000000..ec5c9f20c
--- /dev/null
+++ b/src/include/kernel/spte.H
@@ -0,0 +1,87 @@
+/** @file spte.H
+ *  @brief Defines the structure of the Shadow Page Table Entry.
+ */
+#ifndef __KERNEL_SPTE_H
+#define __KERNEL_SPTE_H
+
+#include <stdint.h>
+#include <builtins.h>
+
+/** @class ShadowPTE
+ *  @brief Stores information needed in a shadow page table for virtual to
+ *         physical address mapping, such as physical page number and
+ *         security permissions.
+ *
+ *  @note This structure only allows addressing of 4GB of physical memory due
+ *        to the page number being stored in a 20 bit field.
+ *
+ *  The data within is stored in a way so that the union value is an address
+ *  within the physical page who's number is stored and the low-order bits
+ *  are used for storing misc information about the page, such as permissions.
+ */
+class ShadowPTE
+{
+    protected:
+        union
+        {
+            uint32_t word;
+            struct
+            {
+                    /** Physical page number. */
+                uint32_t page:20;
+                    /** Page is present (is PN valid?). */
+                uint32_t present:1;
+
+                    /** May the page be written to. */
+                uint32_t writable:1;
+                    /** May code be executed off page. */
+                uint32_t executable:1;
+
+                    /** Should the dirty bit be maintained. */
+                uint32_t track_write:1;
+                    /** Has page been written to. */
+                uint32_t dirty:1;
+
+                    /** Reserved for future use. */
+                uint32_t reserved:7;
+            } PACKED;
+        };
+
+    public:
+            /** Initialize PTE */
+        ShadowPTE() : word(0) {};
+            /** Cast-construct from integer directly to the data union. */
+        explicit ShadowPTE(uint32_t i_data) : word(i_data) {};
+
+            /** Get physical page (as address). */
+        uint32_t getPageAddr() const { return (page << 12); };
+            /** Set physical page (as address). */
+        void setPageAddr(uint32_t i_page) { page = (i_page >> 12); };
+            /** Get physical page (as page number). */
+        uint32_t getPage() const { return page; }
+
+            /** Get present bit. */
+        bool isPresent() const { return present; };
+            /** Set present bit. */
+        void setPresent(bool i_present) { present = i_present; };
+
+            /** Get writable bit. */
+        bool isWritable() const { return writable; };
+            /** Set writable bit. */
+        void setWritable(bool i_write) { writable = i_write; };
+            /** Get executable bit. */
+        bool isExecutable() const { return executable; };
+            /** Set executable bit. */
+        void setExecutable(bool i_exec) { executable = i_exec; };
+
+            /** Get write-tracked bit. */
+        bool isWriteTracked() const { return track_write; };
+            /** Set write-tracked bit. */
+        void setWriteTracked(bool i_track) { track_write = i_track; };
+            /** Get dirty bit. */
+        bool isDirty() const { return dirty; };
+            /** Set dirty bit. */
+        void setDirty(bool i_dirty) { dirty = i_dirty; };
+};
+
+#endif
-- 
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