fix: add MappedFile region type, downgrade MemoryRegionType to pub(crate), fix clippy

- Add MemoryRegionType::MappedFile variant for map_file_cow regions

- Downgrade MemoryRegionType from pub to pub(crate) (not part of public API)

- Use MappedFile consistently on both Windows and Linux in map_file_cow

- Replace disallowed debug_assert_eq! with tracing::warn! in surrogate_process

- Fix Justfile merge conflict

Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

Author: simongdavies

src/hyperlight_host/src/hypervisor/surrogate_process.rs

@@ -82,14 +82,14 @@ impl SurrogateProcess {
     ) -> Result<*mut c_void> {
         match self.mappings.entry(host_base) {
             Entry::Occupied(mut oe) => {
-                debug_assert_eq!(
-                    oe.get().mapping_type,
-                    *mapping,
-                    "Conflicting SurrogateMapping for host_base {host_base:#x}: \
-                     existing={:?}, requested={:?}",
-                    oe.get().mapping_type,
-                    mapping
-                );
+                if oe.get().mapping_type != *mapping {
+                    tracing::warn!(
+                        "Conflicting SurrogateMapping for host_base {host_base:#x}: \
+                         existing={:?}, requested={:?}",
+                        oe.get().mapping_type,
+                        mapping
+                    );
+                }
                 oe.get_mut().use_count += 1;
                 Ok(oe.get().surrogate_base)
             }

src/hyperlight_host/src/mem/memory_region.rs

@@ -112,10 +112,13 @@ impl TryFrom<hv_x64_memory_intercept_message> for MemoryRegionFlags {
     }
 }
 
-// only used for debugging
+// NOTE: In the future, all host-side knowledge about memory region types
+// should collapse down to Snapshot vs Scratch (see shared_mem.rs).
+// Until then, these variants help distinguish regions for diagnostics
+// and crash dumps. Not part of the public API.
 #[derive(Debug, PartialEq, Eq, Copy, Clone, Hash)]
 /// The type of memory region
-pub enum MemoryRegionType {
+pub(crate) enum MemoryRegionType {
     /// The region contains the guest's code
     Code,
     /// The region contains the guest's init data
@@ -128,6 +131,11 @@ pub enum MemoryRegionType {
     Scratch,
     /// The snapshot region
     Snapshot,
+    /// An externally-mapped file (via [`MultiUseSandbox::map_file_cow`]).
+    /// These regions are backed by file handles (Windows) or mmap
+    /// (Linux) and are read-only + executable. They are cleaned up
+    /// during restore/drop — not part of the guest's own allocator.
+    MappedFile,
 }
 
 /// A trait that distinguishes between different kinds of memory region representations.

src/hyperlight_host/src/sandbox/initialized_multi_use.rs

@@ -691,7 +691,7 @@ impl MultiUseSandbox {
                 host_region: host_base..host_end,
                 guest_region: guest_base as usize..guest_base as usize + size,
                 flags: MemoryRegionFlags::READ | MemoryRegionFlags::EXECUTE,
-                region_type: MemoryRegionType::Code,
+                region_type: MemoryRegionType::MappedFile,
             };
 
             // Reset snapshot since we are mutating the sandbox state
@@ -746,7 +746,7 @@ impl MultiUseSandbox {
                 host_region: base as usize..base.wrapping_add(size) as usize,
                 guest_region: guest_base as usize..guest_base as usize + size,
                 flags: MemoryRegionFlags::READ | MemoryRegionFlags::EXECUTE,
-                region_type: MemoryRegionType::Code,
+                region_type: MemoryRegionType::MappedFile,
             }) {
                 libc::munmap(base, size);
                 return Err(err);