[trace-guest] move invariant_tsc logic to separate module

Signed-off-by: Doru Blânzeanu <[email protected]>

Author: dblnz

src/hyperlight_guest_tracing/src/invariant_tsc.rs

@@ -0,0 +1,47 @@
+/*
+Copyright 2025  The Hyperlight Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/// Module for checking invariant TSC support and reading the timestamp counter
+use core::arch::x86_64::{__cpuid, _rdtsc};
+
+/// Check if the processor supports invariant TSC
+///
+/// Returns true if CPUID.80000007H:EDX[8] is set, indicating invariant TSC support
+pub fn has_invariant_tsc() -> bool {
+    // Check if extended CPUID functions are available
+    let max_extended = unsafe { __cpuid(0x80000000) };
+    if max_extended.eax < 0x80000007 {
+        return false;
+    }
+
+    // Query CPUID.80000007H for invariant TSC support
+    let cpuid_result = unsafe { __cpuid(0x80000007) };
+
+    // Check bit 8 of EDX register for invariant TSC support
+    (cpuid_result.edx & (1 << 8)) != 0
+}
+
+/// Read the timestamp counter
+///
+/// This function provides a high-performance timestamp by reading the TSC.
+/// Should only be used when invariant TSC is supported for reliable timing.
+///
+/// # Safety
+/// This function uses unsafe assembly instructions but is safe to call.
+/// However, the resulting timestamp is only meaningful if invariant TSC is supported.
+pub fn read_tsc() -> u64 {
+    unsafe { _rdtsc() }
+}

src/hyperlight_guest_tracing/src/lib.rs

@@ -13,38 +13,9 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
-#![no_std]
-
-/// Module for checking invariant TSC support and reading the timestamp counter
-pub mod invariant_tsc {
-    use core::arch::x86_64::{__cpuid, _rdtsc};
-
-    /// Check if the processor supports invariant TSC
-    ///
-    /// Returns true if CPUID.80000007H:EDX[8] is set, indicating invariant TSC support
-    pub fn has_invariant_tsc() -> bool {
-        // Check if extended CPUID functions are available
-        let max_extended = unsafe { __cpuid(0x80000000) };
-        if max_extended.eax < 0x80000007 {
-            return false;
-        }
 
-        // Query CPUID.80000007H for invariant TSC support
-        let cpuid_result = unsafe { __cpuid(0x80000007) };
-
-        // Check bit 8 of EDX register for invariant TSC support
-        (cpuid_result.edx & (1 << 8)) != 0
-    }
+#![no_std]
+use heapless as hl;
 
-    /// Read the timestamp counter
-    ///
-    /// This function provides a high-performance timestamp by reading the TSC.
-    /// Should only be used when invariant TSC is supported for reliable timing.
-    ///
-    /// # Safety
-    /// This function uses unsafe assembly instructions but is safe to call.
-    /// However, the resulting timestamp is only meaningful if invariant TSC is supported.
-    pub fn read_tsc() -> u64 {
-        unsafe { _rdtsc() }
-    }
-}
+/// Expose invariant TSC module
+pub mod invariant_tsc;