test: add intergration test for physical counter reset

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

Author: ShadowCurse

tests/integration_tests/functional/test_snapshot_basic.py

@@ -2,6 +2,7 @@
 # SPDX-License-Identifier: Apache-2.0
 """Basic tests scenarios for snapshot save/restore."""
 
+import platform
 import filecmp
 import logging
 import os
@@ -11,7 +12,9 @@
 from pathlib import Path
 
 import pytest
+from framework import utils
 
+import host_tools.cargo_build as host
 import host_tools.drive as drive_tools
 from framework.microvm import SnapshotType
 from framework.utils import check_filesystem, check_output
@@ -29,6 +32,7 @@
 # Kernel emits this message when it resumes from a snapshot with VMGenID device
 # present
 DMESG_VMGENID_RESUME = "random: crng reseeded due to virtual machine fork"
+PLATFORM = platform.machine()
 
 
 def check_vmgenid_update_count(vm, resume_count):
@@ -540,3 +544,41 @@ def test_vmgenid(guest_kernel_linux_6_1, rootfs, microvm_factory, snapshot_type)
 
         # Update the base for next iteration
         base_snapshot = snapshot
+
+
+# @pytest.mark.skipif(
+#    platform != "aarch64",
+#    reason="This is aarch64 specific test.",
+# )
+def test_physical_couter_reset_aarch64(uvm_nano, microvm_factory):
+    """
+    Test that the CNTPCT_EL0 register is reset on VM boot.
+    Because we cannot read the CNTVCT_EL0 (Virtual counter)
+    from python, we assume the smallesd VM will not consume more than
+    MAX_VALUE cycles to be created and snapshotted.
+    """
+    vm = uvm_nano
+    vm.add_net_iface()
+    vm.start()
+
+    snapshot = vm.snapshot_full()
+    vm.kill()
+    snap_editor = host.get_binary("snapshot-editor")
+
+    CNTPCT_EL0 = hex(0x603000000013DF01)
+    MAX_VALUE = 800_000_000
+
+    cmd = [
+        str(snap_editor),
+        "info-vmstate",
+        "vcpu-states",
+        "--vmstate-path",
+        str(snapshot.vmstate),
+    ]
+    _, stdout, _ = utils.check_output(cmd)
+    for line in stdout.splitlines():
+        s = line.split(" ")
+        if len(s) == 2:
+            reg_id, reg_value = line.split(" ")
+            if reg_id == CNTPCT_EL0:
+                assert int(reg_value, 16) < MAX_VALUE