test: add intergration test for physical counter reset

Signed-off-by: Egor Lazarchuk <[email protected]>

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
@@ -25,6 +28,7 @@
     make_host_port_path,
     start_guest_echo_server,
 )
+from framework.properties import global_props
 
 # Kernel emits this message when it resumes from a snapshot with VMGenID device
 # present
@@ -540,3 +544,50 @@ 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.machine() != "aarch64"
+    or not global_props.is_ec2
+    or global_props.host_linux_version_tpl < (6, 4),
+    reason="This is aarch64 specific test and should only be run on ",
+)
+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. We have to use
+    this approach because we cannot get host counter value from Python.
+    """
+    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)
+
+    # The output will look like this:
+    # kvm_mp_state: 0x0
+    # mpidr: 0x80000000
+    # 0x6030000000100000 0x0000000e0
+    # 0x6030000000100002 0xffff00fe33c0
+    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