xenia-kernel: HLE expansion, scheduler integration, audit + UI bridge

Major HLE buildout in exports.rs: KeInitializeSemaphore now seeds
count/limit, XexGet{Module,Procedure}Address use distinct
HMODULE_XBOXKRNL/HMODULE_XAM pseudo-handles with a reverse
(ModuleId,ordinal)→thunk_addr map, plus sweeping additions across
sync primitives, file I/O, semaphores, events, threads, and
allocator paths needed to advance Sylpheed past VdSwap=2.

New modules:
  - thread.rs   — ThreadRef + per-thread suspension/wake plumbing
  - interrupts.rs — IRQ delivery, pending-IRQ slots, IPI helpers
  - path.rs     — guest path normalization (D:\\, game:\\, etc.)
  - audit.rs    — --trace-handles harness backing the handle audit
  - ui_bridge.rs — kernel-side endpoint of the xenia-ui bridge
                   (input snapshots, framebuffer publish handles)

state.rs grows to own the HW-slot scheduler state, the new audit /
UI bridge handles, and the per-handle reverse maps. xam.rs and
objects.rs follow suit for the HLE additions.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/xenia-kernel/src/path.rs

@@ -0,0 +1,139 @@
+//! Path normalization for kernel file I/O.
+//!
+//! Guests pass file paths inside an `OBJECT_ATTRIBUTES` struct that points at
+//! an `ANSI_STRING` descriptor. Those paths come in several Xbox-flavored
+//! forms — NT device paths (`\Device\Cdrom0\...`), drive letters (`D:\...`,
+//! `d:\...`), or symbolic link prefixes (`game:\...`). We strip whichever
+//! prefix applies and return a plain slash-separated path relative to the
+//! mounted VFS root, so `VfsDevice::read_file` can look it up directly.
+
+use xenia_memory::{GuestMemory, MemoryAccess};
+
+/// Xbox `ANSI_STRING`:
+///   u16 Length
+///   u16 MaximumLength
+///   u32 Buffer (guest pointer)
+fn read_ansi_string(mem: &GuestMemory, ptr: u32) -> Option<String> {
+    if ptr == 0 {
+        return None;
+    }
+    let length = mem.read_u16(ptr) as u32;
+    let buffer = mem.read_u32(ptr + 4);
+    if buffer == 0 || length == 0 {
+        return Some(String::new());
+    }
+    let mut out = String::with_capacity(length as usize);
+    for i in 0..length {
+        let c = mem.read_u8(buffer + i);
+        if c == 0 {
+            break;
+        }
+        out.push(c as char);
+    }
+    Some(out)
+}
+
+/// Xbox `OBJECT_ATTRIBUTES`:
+///   u32 RootDirectory (handle)
+///   u32 Name          (pointer to ANSI_STRING)
+///   u32 Attributes
+fn read_object_attributes_name(mem: &GuestMemory, obj_attrs_ptr: u32) -> Option<String> {
+    if obj_attrs_ptr == 0 {
+        return None;
+    }
+    let name_ptr = mem.read_u32(obj_attrs_ptr + 4);
+    read_ansi_string(mem, name_ptr)
+}
+
+/// Known Xbox device prefixes that need to be stripped before looking a path
+/// up in the VFS. The list mirrors the symbolic links xenia-canary sets up
+/// at boot (see `xboxkrnl_io.cc`). Case-insensitive matching.
+const DEVICE_PREFIXES: &[&str] = &[
+    "\\Device\\Cdrom0\\",
+    "\\Device\\Harddisk0\\Partition1\\",
+    "\\Device\\Harddisk0\\Partition0\\",
+    "\\Device\\Harddisk0\\",
+    "\\Device\\Mu0\\",
+    "\\Device\\Mu1\\",
+    "\\Device\\Mass0\\",
+    "\\Device\\Mass1\\",
+    "\\Device\\Mass2\\",
+    "\\SystemRoot\\",
+    "\\??\\",
+    "game:\\",
+    "d:\\",
+    "D:\\",
+];
+
+/// Strip any Xbox device prefix and normalize backslashes to forward slashes.
+/// Returns the path relative to the VFS root.
+pub fn normalize_path(raw: &str) -> String {
+    let mut s = raw.trim().to_string();
+
+    // Case-insensitive prefix strip.
+    let lowered = s.to_ascii_lowercase();
+    for prefix in DEVICE_PREFIXES {
+        let pl = prefix.to_ascii_lowercase();
+        if lowered.starts_with(&pl) {
+            s = s[pl.len()..].to_string();
+            break;
+        }
+    }
+
+    // Drop any leading slash/backslash that survived prefix stripping.
+    while s.starts_with('\\') || s.starts_with('/') {
+        s.remove(0);
+    }
+
+    // Canonical form: forward slashes.
+    s.replace('\\', "/")
+}
+
+/// Convenience: read the OBJECT_ATTRIBUTES struct at `obj_attrs_ptr` and
+/// return a normalized VFS path. Returns `None` if the struct pointer or its
+/// inner name pointer is null.
+pub fn object_attributes_to_vfs_path(mem: &GuestMemory, obj_attrs_ptr: u32) -> Option<String> {
+    let raw = read_object_attributes_name(mem, obj_attrs_ptr)?;
+    if raw.is_empty() {
+        return None;
+    }
+    Some(normalize_path(&raw))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn strips_device_cdrom() {
+        assert_eq!(normalize_path("\\Device\\Cdrom0\\default.xex"), "default.xex");
+    }
+
+    #[test]
+    fn strips_drive_letter_lowercase() {
+        assert_eq!(normalize_path("d:\\media\\shared\\foo.pkg"), "media/shared/foo.pkg");
+    }
+
+    #[test]
+    fn strips_drive_letter_uppercase() {
+        assert_eq!(normalize_path("D:\\default.xex"), "default.xex");
+    }
+
+    #[test]
+    fn strips_game_prefix() {
+        assert_eq!(normalize_path("game:\\data\\whatever.bin"), "data/whatever.bin");
+    }
+
+    #[test]
+    fn preserves_relative_path() {
+        assert_eq!(normalize_path("scripts/init.lua"), "scripts/init.lua");
+    }
+
+    #[test]
+    fn handles_partition1() {
+        assert_eq!(
+            normalize_path("\\Device\\Harddisk0\\Partition1\\content\\abc.sav"),
+            "content/abc.sav"
+        );
+    }
+}