core/memory: Check our memory fallbacks for out-of-bound behavior.

This makes it by far harder to crash yuzu.

Also implement the 48bit masking of AARCH64 while touching this code.

2 files changed, 7 insertions, 0 deletions

diff --git a/src/common/page_table.cpp b/src/common/page_table.cpp
index 8fd8620fd..9fffd816f 100644
--- a/src/common/page_table.cpp
+++ b/src/common/page_table.cpp
@@ -14,6 +14,7 @@ void PageTable::Resize(size_t address_space_width_in_bits, size_t page_size_in_b
     const size_t num_page_table_entries{1ULL << (address_space_width_in_bits - page_size_in_bits)};
     pointers.resize(num_page_table_entries);
     backing_addr.resize(num_page_table_entries);
+    current_address_space_width_in_bits = address_space_width_in_bits;
 }
 
 } // namespace Common
diff --git a/src/common/page_table.h b/src/common/page_table.h
index 61c5552e0..e92b66b2b 100644
--- a/src/common/page_table.h
+++ b/src/common/page_table.h
@@ -98,6 +98,10 @@ struct PageTable {
      */
     void Resize(size_t address_space_width_in_bits, size_t page_size_in_bits);
 
+    size_t GetAddressSpaceBits() const {
+        return current_address_space_width_in_bits;
+    }
+
     /**
      * Vector of memory pointers backing each page. An entry can only be non-null if the
      * corresponding attribute element is of type `Memory`.
@@ -105,6 +109,8 @@ struct PageTable {
     VirtualBuffer<PageInfo> pointers;
 
     VirtualBuffer<u64> backing_addr;
+
+    size_t current_address_space_width_in_bits;
 };
 
 } // namespace Common