1 files changed, 84 insertions, 0 deletions
diff --git a/python/qemu/utils/accel.py b/python/qemu/utils/accel.py
new file mode 100644
index 000000000..386ff640c
--- /dev/null
+++ b/python/qemu/utils/accel.py
@@ -0,0 +1,84 @@
+"""
+QEMU accel module:
+
+This module provides utilities for discover and check the availability of
+accelerators.
+"""
+# Copyright (C) 2015-2016 Red Hat Inc.
+# Copyright (C) 2012 IBM Corp.
+#
+# Authors:
+#  Fam Zheng <famz@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2.  See
+# the COPYING file in the top-level directory.
+#
+
+import logging
+import os
+import subprocess
+from typing import List, Optional
+
+
+LOG = logging.getLogger(__name__)
+
+# Mapping host architecture to any additional architectures it can
+# support which often includes its 32 bit cousin.
+ADDITIONAL_ARCHES = {
+    "x86_64": "i386",
+    "aarch64": "armhf",
+    "ppc64le": "ppc64",
+}
+
+
+def list_accel(qemu_bin: str) -> List[str]:
+    """
+    List accelerators enabled in the QEMU binary.
+
+    @param qemu_bin (str): path to the QEMU binary.
+    @raise Exception: if failed to run ``qemu -accel help``
+    @return a list of accelerator names.
+    """
+    if not qemu_bin:
+        return []
+    try:
+        out = subprocess.check_output([qemu_bin, '-accel', 'help'],
+                                      universal_newlines=True)
+    except:
+        LOG.debug("Failed to get the list of accelerators in %s", qemu_bin)
+        raise
+    # Skip the first line which is the header.
+    return [acc.strip() for acc in out.splitlines()[1:]]
+
+
+def kvm_available(target_arch: Optional[str] = None,
+                  qemu_bin: Optional[str] = None) -> bool:
+    """
+    Check if KVM is available using the following heuristic:
+      - Kernel module is present in the host;
+      - Target and host arches don't mismatch;
+      - KVM is enabled in the QEMU binary.
+
+    @param target_arch (str): target architecture
+    @param qemu_bin (str): path to the QEMU binary
+    @return True if kvm is available, otherwise False.
+    """
+    if not os.access("/dev/kvm", os.R_OK | os.W_OK):
+        return False
+    if target_arch:
+        host_arch = os.uname()[4]
+        if target_arch != host_arch:
+            if target_arch != ADDITIONAL_ARCHES.get(host_arch):
+                return False
+    if qemu_bin and "kvm" not in list_accel(qemu_bin):
+        return False
+    return True
+
+
+def tcg_available(qemu_bin: str) -> bool:
+    """
+    Check if TCG is available.
+
+    @param qemu_bin (str): path to the QEMU binary
+    """
+    return 'tcg' in list_accel(qemu_bin)