make ReadBlockunsafe and WriteBlockunsafe, ignore invalid pages.

src/video_core/memory_manager.cpp

@@ -243,8 +243,13 @@ void MemoryManager::ReadBlockUnsafe(GPUVAddr src_addr, void* dest_buffer,
     while (remaining_size > 0) {
         const std::size_t copy_amount{
             std::min(static_cast<std::size_t>(page_size) - page_offset, remaining_size)};
-        const u8* src_ptr{page_table.pointers[page_index] + page_offset};
-        std::memcpy(dest_buffer, src_ptr, copy_amount);
+        const u8* page_pointer = page_table.pointers[page_index];
+        if (page_pointer) {
+            const u8* src_ptr{page_pointer + page_offset};
+            std::memcpy(dest_buffer, src_ptr, copy_amount);
+        } else {
+            std::memset(dest_buffer, 0, copy_amount);
+        }
         page_index++;
         page_offset = 0;
         dest_buffer = static_cast<u8*>(dest_buffer) + copy_amount;
@@ -288,8 +293,11 @@ void MemoryManager::WriteBlockUnsafe(GPUVAddr dest_addr, const void* src_buffer,
     while (remaining_size > 0) {
         const std::size_t copy_amount{
             std::min(static_cast<std::size_t>(page_size) - page_offset, remaining_size)};
-        u8* dest_ptr{page_table.pointers[page_index] + page_offset};
-        std::memcpy(dest_ptr, src_buffer, copy_amount);
+        u8* page_pointer = page_table.pointers[page_index];
+        if (page_pointer) {
+            u8* dest_ptr{page_pointer + page_offset};
+            std::memcpy(dest_ptr, src_buffer, copy_amount);
+        }
         page_index++;
         page_offset = 0;
         src_buffer = static_cast<const u8*>(src_buffer) + copy_amount;