[Qemu-devel] [PATCH 2/3] tests/acceptance: Introduce the "accel" tag

[Wainer dos Santos Moschetta <wainersm@redhat.com>]

Some test cases may boot a VM with accelerator that isn't actually
enabled on the QEMU binary or present in the host. In this case
the test case is gonna fail miserably, unless it can be skipped.

This change introduces the "accel" tag, used to mark the test
case requires a given accelerator(s). It was implemented a
mechanism to check the given accelerator is available, and if not
then the test case is skipped.

Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
---
 tests/acceptance/avocado_qemu/__init__.py |  5 ++
 tests/acceptance/avocado_qemu/accel.py    | 60 +++++++++++++++++++++++
 2 files changed, 65 insertions(+)
 create mode 100644 tests/acceptance/avocado_qemu/accel.py

diff --git a/tests/acceptance/avocado_qemu/__init__.py b/tests/acceptance/avocado_qemu/__init__.py
index 2b236a1cf0..f823f7525b 100644
--- a/tests/acceptance/avocado_qemu/__init__.py
+++ b/tests/acceptance/avocado_qemu/__init__.py
@@ -18,6 +18,7 @@ SRC_ROOT_DIR = os.path.join(os.path.dirname(__file__), '..', '..', '..')
 sys.path.append(os.path.join(SRC_ROOT_DIR, 'python'))
 
 from qemu import QEMUMachine
+from .accel import is_accel_available
 
 def is_readable_executable_file(path):
     return os.path.isfile(path) and os.access(path, os.R_OK | os.X_OK)
@@ -65,6 +66,10 @@ class Test(avocado.Test):
         if self.qemu_bin is None:
             self.cancel("No QEMU binary defined or found in the source tree")
 
+        for accel in self.tags.get('accel', []):
+            if not is_accel_available(accel, self.qemu_bin):
+                self.cancel("Accelerator %s not available" % accel)
+
     def _new_vm(self, *args):
         vm = QEMUMachine(self.qemu_bin)
         if args:
diff --git a/tests/acceptance/avocado_qemu/accel.py b/tests/acceptance/avocado_qemu/accel.py
new file mode 100644
index 0000000000..21f7240d56
--- /dev/null
+++ b/tests/acceptance/avocado_qemu/accel.py
@@ -0,0 +1,60 @@
+# Utilities for using QEMU accelerators on tests.
+#
+# Copyright (c) 2019 Red Hat, Inc.
+#
+# Author:
+#  Wainer dos Santos Moschetta <wainersm@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later.  See the COPYING file in the top-level directory.
+
+from qemu import QEMUMachine
+from qemu import kvm_available
+
+def list_accel(qemu_bin):
+    """
+    List accelerators enabled in the binary.
+
+    :param qemu_bin: path to the QEMU binary.
+    :type qemu_bin: str
+    :returns: list of accelerator names.
+    :rtype: list
+    """
+    vm = QEMUMachine(qemu_bin)
+    vm.set_qmp_monitor(disabled=True)
+    vm.add_args('-accel', 'help')
+    vm.launch()
+    vm.wait()
+    if vm.exitcode() != 0:
+        raise Exception("Failed to get the accelerators in %s" % qemu_bin)
+    lines = vm.get_log().splitlines()
+    # skip first line which is the output header.
+    return [l for l in lines[1:] if l]
+
+def _tcg_avail_checker(qemu_bin):
+    # checks TCG is enabled in the binary only.
+    return 'tcg' in list_accel(qemu_bin)
+
+def _kvm_avail_checker(qemu_bin):
+    # checks KVM is present in the host as well as enabled in the binary.
+    return kvm_available() and "kvm" in list_accel(qemu_bin)
+
+_CHECKERS = {"tcg": _tcg_avail_checker, "kvm": _kvm_avail_checker}
+
+def is_accel_available(accel, qemu_bin):
+    """
+    Check the accelerator is available (enabled in the binary as well as
+    present on host).
+
+    :param accel:  accelerator's name.
+    :type accel: str
+    :param qemu_bin: path to the QEMU binary.
+    :type qemu_bin: str
+    :returns: True if accelerator is available, False otherwise.
+    :rtype: boolean
+    """
+    checker = _CHECKERS.get(accel, None)
+    if checker:
+        return checker(qemu_bin)
+    raise Exception("Availability checker not implemented for %s accelerator." %
+                    accel)
-- 
2.21.0