tests: Add integration test for virtio-vsock device reset

Add a test that verifies virtio-vsock device reset works end-to-end by
unbinding and rebinding the guest driver and checking the device
remains functional.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Author: ilstam

tests/integration_tests/functional/test_vsock.py

@@ -367,3 +367,44 @@ def test_vsock_override_fails_without_device(uvm_plain_any, microvm_factory):
         )
 
     vm2.mark_killed()
+
+
+def test_device_reset(uvm_plain_any):
+    """
+    Test that virtio-vsock device reset works.
+    """
+    vm = uvm_plain_any
+    vm.spawn()
+    vm.basic_config()
+    vm.add_net_iface()
+    vm.api.vsock.put(guest_cid=3, vsock_id="vsock0", uds_path="/" + VSOCK_UDS_PATH)
+    vm.start()
+
+    # Establish a vsock connection before reset so there is active state in the
+    # backend that must be cleaned up.
+    uds_path = start_guest_echo_server(vm)
+    blob_path, blob_hash = make_blob(vm.path)
+    check_host_connections(uds_path, blob_path, blob_hash)
+
+    # Find the virtio vsock device.
+    virtio_dev = vm.ssh.check_output(
+        "ls -d /sys/bus/virtio/drivers/vmw_vsock_virtio_transport/virtio*"
+        " | xargs -n1 basename"
+    ).stdout.strip()
+
+    vm.ssh.check_output(
+        f"echo {virtio_dev} > /sys/bus/virtio/drivers/vmw_vsock_virtio_transport/unbind"
+    )
+
+    # Verify the vsock device is gone.
+    ret = vm.ssh.run("ls /sys/bus/virtio/drivers/vmw_vsock_virtio_transport/virtio*")
+    assert ret.returncode != 0
+
+    # Rebind and verify the data path works by starting a guest echo server
+    # and sending data from the host through the vsock.
+    vm.ssh.check_output(
+        f"echo {virtio_dev} > /sys/bus/virtio/drivers/vmw_vsock_virtio_transport/bind"
+    )
+    uds_path = start_guest_echo_server(vm)
+    blob_path, blob_hash = make_blob(vm.path)
+    check_host_connections(uds_path, blob_path, blob_hash)