xemu/python/qemu/accel.py
Wainer dos Santos Moschetta d3ca7bb599 python/qemu: accel: Add tcg_available() method
This adds a method to check if the tcg accelerator is enabled
in the QEMU binary.

Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Cleber Rosa <crosa@redhat.com>
Message-Id: <20191216191438.93418-5-wainersm@redhat.com>
Signed-off-by: Cleber Rosa <crosa@redhat.com>
2019-12-16 18:39:04 -05:00

78 lines
2.1 KiB
Python

"""
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
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"
}
def list_accel(qemu_bin):
"""
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=None, qemu_bin=None):
"""
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):
"""
Check if TCG is available.
@param qemu_bin (str): path to the QEMU binary
"""
return 'tcg' in list_accel(qemu_bin)