core: memory: page_table: Make PageTable class thread safe.

src/common/page_table.h

@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <mutex>
 #include <tuple>
 
 #include "common/common_types.h"
@@ -47,7 +48,8 @@ struct SpecialRegion {
  * A (reasonably) fast way of allowing switchable and remappable process address spaces. It loosely
  * mimics the way a real CPU page table works.
  */
-struct PageTable {
+class PageTable {
+public:
     PageTable();
     ~PageTable() noexcept;
 
@@ -62,12 +64,42 @@ struct PageTable {
      * a given address space.
      *
      * @param address_space_width_in_bits The address size width in bits.
-     * @param page_size_in_bits           The page size in bits.
-     * @param has_attribute               Whether or not this page has any backing attributes.
+     * @param page_size_in_bits The page size in bits.
      */
-    void Resize(std::size_t address_space_width_in_bits, std::size_t page_size_in_bits,
-                bool has_attribute);
+    void Resize(std::size_t address_space_width_in_bits, std::size_t page_size_in_bits);
 
+    struct Entry {
+        u8* const pointer;
+        const u64 backing_addr;
+        const Common::PageType attribute;
+    };
+
+    VirtualBuffer<u8*>& GetPointers() {
+        return pointers;
+    }
+
+    u64 GetBackingAddr(std::size_t base) {
+        std::lock_guard<std::mutex> lock(guard);
+        return backing_addr[base];
+    }
+
+    Entry GetEntry(std::size_t base) {
+        std::lock_guard<std::mutex> lock(guard);
+        return {
+            .pointer = pointers[base],
+            .backing_addr = backing_addr[base],
+            .attribute = attributes[base],
+        };
+    }
+
+    void SetEntry(std::size_t base, const Entry& entry) {
+        std::lock_guard<std::mutex> lock(guard);
+        pointers[base] = entry.pointer;
+        backing_addr[base] = entry.backing_addr;
+        attributes[base] = entry.attribute;
+    }
+
+private:
     /**
      * Vector of memory pointers backing each page. An entry can only be non-null if the
      * corresponding entry in the `attributes` vector is of type `Memory`.
@@ -77,6 +109,8 @@ struct PageTable {
     VirtualBuffer<u64> backing_addr;
 
     VirtualBuffer<PageType> attributes;
+
+    std::mutex guard;
 };
 
 } // namespace Common