kernel/tests: don't rely on vector for fake memory

1 files changed, 18 insertions, 2 deletions

diff --git a/kernel/src/test_support/page_mapper.cpp b/kernel/src/test_support/page_mapper.cpp
index 5a1b747..805998b 100644
--- a/kernel/src/test_support/page_mapper.cpp
+++ b/kernel/src/test_support/page_mapper.cpp
@@ -7,6 +7,7 @@
 #include <cstddef>
 #include <format>
 #include <stdexcept>
+#include <sys/mman.h>
 
 namespace kernel::tests
 {
@@ -20,10 +21,25 @@ namespace kernel::tests
     page_mappings.insert({page.number(), frame});
 
     auto page_address = page.start_address();
+    auto sandbox_start = memory.heap_base();
+    auto sandbox_end = sandbox_start + memory.heap_size();
 
-    if (page_address >= kapi::memory::mmio_base)
+    if (page_address >= sandbox_start && page_address < sandbox_end)
     {
-      throw std::invalid_argument{"MMIO mapping not yet supported in testing!"};
+      auto virtual_target = static_cast<std::byte *>(page_address);
+      auto physical_offset = frame.number() * kapi::memory::frame::size;
+      auto mapped_ptr = mmap(virtual_target, kapi::memory::page::size.value, PROT_READ | PROT_WRITE,
+                             MAP_SHARED | MAP_FIXED, memory.memory_descriptor(), physical_offset.value);
+      if (mapped_ptr == MAP_FAILED)
+      {
+        throw std::runtime_error("Failed to map page");
+      }
+
+      return static_cast<std::byte *>(mapped_ptr);
+    }
+    else if (page_address >= kapi::memory::mmio_base)
+    {
+      throw std::runtime_error("MMIO mapping not yet supported in testing!");
     }
     else if (page_address >= kapi::memory::higher_half_direct_map_base)
     {