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-rw-r--r--src/common/page_table.cpp12
-rw-r--r--src/common/page_table.h15
2 files changed, 24 insertions, 3 deletions
diff --git a/src/common/page_table.cpp b/src/common/page_table.cpp
index 69b7abc54..566b57b62 100644
--- a/src/common/page_table.cpp
+++ b/src/common/page_table.cpp
@@ -16,7 +16,6 @@ void PageTable::Resize(std::size_t address_space_width_in_bits) {
pointers.resize(num_page_table_entries);
attributes.resize(num_page_table_entries);
- backing_addr.resize(num_page_table_entries);
// The default is a 39-bit address space, which causes an initial 1GB allocation size. If the
// vector size is subsequently decreased (via resize), the vector might not automatically
@@ -25,6 +24,17 @@ void PageTable::Resize(std::size_t address_space_width_in_bits) {
pointers.shrink_to_fit();
attributes.shrink_to_fit();
+}
+
+BackingPageTable::BackingPageTable(std::size_t page_size_in_bits) : PageTable{page_size_in_bits} {}
+
+BackingPageTable::~BackingPageTable() = default;
+
+void BackingPageTable::Resize(std::size_t address_space_width_in_bits) {
+ PageTable::Resize(address_space_width_in_bits);
+ const std::size_t num_page_table_entries = 1ULL
+ << (address_space_width_in_bits - page_size_in_bits);
+ backing_addr.resize(num_page_table_entries);
backing_addr.shrink_to_fit();
}
diff --git a/src/common/page_table.h b/src/common/page_table.h
index 8b8ff0bb8..dbc272ab7 100644
--- a/src/common/page_table.h
+++ b/src/common/page_table.h
@@ -76,9 +76,20 @@ struct PageTable {
*/
std::vector<PageType> attributes;
- std::vector<u64> backing_addr;
-
const std::size_t page_size_in_bits{};
};
+/**
+ * A more advanced Page Table with the ability to save a backing address when using it
+ * depends on another MMU.
+ */
+struct BackingPageTable : PageTable {
+ explicit BackingPageTable(std::size_t page_size_in_bits);
+ ~BackingPageTable();
+
+ void Resize(std::size_t address_space_width_in_bits);
+
+ std::vector<u64> backing_addr;
+};
+
} // namespace Common