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numam-dpdk/lib/librte_vhost/libvirt/qemu-wrap.py
Ouyang Changchun d533647a87 vhost: fix qemu shutdown 
This patch originates from the patch:
"Patch for Qemu wrapper for US-VHost to ensure Qemu process ends when
VM is shutdown", http://dpdk.org/ml/archives/dev/2014-June/003606.html

Also update the vhost sample guide doc.

Signed-off-by: Claire Murphy <claire.k.murphy@intel.com>
Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
2015-09-24 14:57:36 +02:00

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#!/usr/bin/python
#/*
# * BSD LICENSE
# *
# * Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
# * All rights reserved.
# *
# * Redistribution and use in source and binary forms, with or without
# * modification, are permitted provided that the following conditions
# * are met:
# *
# * * Redistributions of source code must retain the above copyright
# * notice, this list of conditions and the following disclaimer.
# * * Redistributions in binary form must reproduce the above copyright
# * notice, this list of conditions and the following disclaimer in
# * the documentation and/or other materials provided with the
# * distribution.
# * * Neither the name of Intel Corporation nor the names of its
# * contributors may be used to endorse or promote products derived
# * from this software without specific prior written permission.
# *
# * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# */
#####################################################################
# This script is designed to modify the call to the QEMU emulator
# to support userspace vhost when starting a guest machine through
# libvirt with vhost enabled. The steps to enable this are as follows
# and should be run as root:
#
# 1. Place this script in a libvirtd's binary search PATH ($PATH)
# A good location would be in the same directory that the QEMU
# binary is located
#
# 2. Ensure that the script has the same owner/group and file
# permissions as the QEMU binary
#
# 3. Update the VM xml file using "virsh edit VM.xml"
#
# 3.a) Set the VM to use the launch script
#
# Set the emulator path contained in the
# <emulator><emulator/> tags
#
# e.g replace <emulator>/usr/bin/qemu-kvm<emulator/>
# with <emulator>/usr/bin/qemu-wrap.py<emulator/>
#
# 3.b) Set the VM's device's to use vhost-net offload
#
# <interface type="network">
# <model type="virtio"/>
# <driver name="vhost"/>
# <interface/>
#
# 4. Enable libvirt to access our userpace device file by adding it to
# controllers cgroup for libvirtd using the following steps
#
# 4.a) In /etc/libvirt/qemu.conf add/edit the following lines:
# 1) cgroup_controllers = [ ... "devices", ... ]
# 2) clear_emulator_capabilities = 0
# 3) user = "root"
# 4) group = "root"
# 5) cgroup_device_acl = [
# "/dev/null", "/dev/full", "/dev/zero",
# "/dev/random", "/dev/urandom",
# "/dev/ptmx", "/dev/kvm", "/dev/kqemu",
# "/dev/rtc", "/dev/hpet", "/dev/net/tun",
# "/dev/<devbase-name>",
# "/dev/hugepages",
# ]
#
# 4.b) Disable SELinux or set to permissive mode
#
# 4.c) Mount cgroup device controller
# "mkdir /dev/cgroup"
# "mount -t cgroup none /dev/cgroup -o devices"
#
# 4.d) Set hugetlbfs_mount variable - ( Optional )
# VMs using userspace vhost must use hugepage backed
# memory. This can be enabled in the libvirt XML
# config by adding a memory backing section to the
# XML config e.g.
# <memoryBacking>
# <hugepages/>
# </memoryBacking>
# This memory backing section should be added after the
# <memory> and <currentMemory> sections. This will add
# flags "-mem-prealloc -mem-path <path>" to the QEMU
# command line. The hugetlbfs_mount variable can be used
# to override the default <path> passed through by libvirt.
#
# if "-mem-prealloc" or "-mem-path <path>" are not passed
# through and a vhost device is detected then these options will
# be automatically added by this script. This script will detect
# the system hugetlbfs mount point to be used for <path>. The
# default <path> for this script can be overidden by the
# hugetlbfs_dir variable in the configuration section of this script.
#
#
# 4.e) Restart the libvirtd system process
# e.g. on Fedora "systemctl restart libvirtd.service"
#
#
# 4.f) Edit the Configuration Parameters section of this script
# to point to the correct emulator location and set any
# addition options
#
# The script modifies the libvirtd Qemu call by modifying/adding
# options based on the configuration parameters below.
# NOTE:
# emul_path and us_vhost_path must be set
# All other parameters are optional
#####################################################################
#############################################
# Configuration Parameters
#############################################
#Path to QEMU binary
emul_path = "/usr/local/bin/qemu-system-x86_64"
#Path to userspace vhost device file
# This filename should match the --dev-basename parameters of
# the command used to launch the userspace vhost sample application e.g.
# if the sample app lauch command is:
# ./build/vhost-switch ..... --dev-basename usvhost
# then this variable should be set to:
# us_vhost_path = "/dev/usvhost"
us_vhost_path = "/dev/usvhost"
#List of additional user defined emulation options. These options will
#be added to all Qemu calls
emul_opts_user = []
#List of additional user defined emulation options for vhost only.
#These options will only be added to vhost enabled guests
emul_opts_user_vhost = []
#For all VHOST enabled VMs, the VM memory is preallocated from hugetlbfs
# Set this variable to one to enable this option for all VMs
use_huge_all = 0
#Instead of autodetecting, override the hugetlbfs directory by setting
#this variable
hugetlbfs_dir = ""
#############################################
#############################################
# ****** Do Not Modify Below this Line ******
#############################################
import sys, os, subprocess
import time
import signal
#List of open userspace vhost file descriptors
fd_list = []
#additional virtio device flags when using userspace vhost
vhost_flags = [ "csum=off",
"gso=off",
"guest_tso4=off",
"guest_tso6=off",
"guest_ecn=off"
]
#String of the path to the Qemu process pid
qemu_pid = "/tmp/%d-qemu.pid" % os.getpid()
#############################################
# Signal haldler to kill Qemu subprocess
#############################################
def kill_qemu_process(signum, stack):
pidfile = open(qemu_pid, 'r')
pid = int(pidfile.read())
os.killpg(pid, signal.SIGTERM)
pidfile.close()
#############################################
# Find the system hugefile mount point.
# Note:
# if multiple hugetlbfs mount points exist
# then the first one found will be used
#############################################
def find_huge_mount():
if (len(hugetlbfs_dir)):
return hugetlbfs_dir
huge_mount = ""
if (os.access("/proc/mounts", os.F_OK)):
f = open("/proc/mounts", "r")
line = f.readline()
while line:
line_split = line.split(" ")
if line_split[2] == 'hugetlbfs':
huge_mount = line_split[1]
break
line = f.readline()
else:
print "/proc/mounts not found"
exit (1)
f.close
if len(huge_mount) == 0:
print "Failed to find hugetlbfs mount point"
exit (1)
return huge_mount
#############################################
# Get a userspace Vhost file descriptor
#############################################
def get_vhost_fd():
if (os.access(us_vhost_path, os.F_OK)):
fd = os.open( us_vhost_path, os.O_RDWR)
else:
print ("US-Vhost file %s not found" %us_vhost_path)
exit (1)
return fd
#############################################
# Check for vhostfd. if found then replace
# with our own vhost fd and append any vhost
# flags onto the end
#############################################
def modify_netdev_arg(arg):
global fd_list
vhost_in_use = 0
s = ''
new_opts = []
netdev_opts = arg.split(",")
for opt in netdev_opts:
#check if vhost is used
if "vhost" == opt[:5]:
vhost_in_use = 1
else:
new_opts.append(opt)
#if using vhost append vhost options
if vhost_in_use == 1:
#append vhost on option
new_opts.append('vhost=on')
#append vhostfd ption
new_fd = get_vhost_fd()
new_opts.append('vhostfd=' + str(new_fd))
fd_list.append(new_fd)
#concatenate all options
for opt in new_opts:
if len(s) > 0:
s+=','
s+=opt
return s
#############################################
# Main
#############################################
def main():
global fd_list
global vhost_in_use
new_args = []
num_cmd_args = len(sys.argv)
emul_call = ''
mem_prealloc_set = 0
mem_path_set = 0
num = 0;
#parse the parameters
while (num < num_cmd_args):
arg = sys.argv[num]
#Check netdev +1 parameter for vhostfd
if arg == '-netdev':
num_vhost_devs = len(fd_list)
new_args.append(arg)
num+=1
arg = sys.argv[num]
mod_arg = modify_netdev_arg(arg)
new_args.append(mod_arg)
#append vhost flags if this is a vhost device
# and -device is the next arg
# i.e -device -opt1,-opt2,...,-opt3,%vhost
if (num_vhost_devs < len(fd_list)):
num+=1
arg = sys.argv[num]
if arg == '-device':
new_args.append(arg)
num+=1
new_arg = sys.argv[num]
for flag in vhost_flags:
new_arg = ''.join([new_arg,',',flag])
new_args.append(new_arg)
else:
new_args.append(arg)
elif arg == '-mem-prealloc':
mem_prealloc_set = 1
new_args.append(arg)
elif arg == '-mem-path':
mem_path_set = 1
new_args.append(arg)
else:
new_args.append(arg)
num+=1
#Set Qemu binary location
emul_call+=emul_path
emul_call+=" "
#Add prealloc mem options if using vhost and not already added
if ((len(fd_list) > 0) and (mem_prealloc_set == 0)):
emul_call += "-mem-prealloc "
#Add mempath mem options if using vhost and not already added
if ((len(fd_list) > 0) and (mem_path_set == 0)):
#Detect and add hugetlbfs mount point
mp = find_huge_mount()
mp = "".join(["-mem-path ", mp])
emul_call += mp
emul_call += " "
#add user options
for opt in emul_opts_user:
emul_call += opt
emul_call += " "
#Add add user vhost only options
if len(fd_list) > 0:
for opt in emul_opts_user_vhost:
emul_call += opt
emul_call += " "
#Add updated libvirt options
iter_args = iter(new_args)
#skip 1st arg i.e. call to this script
next(iter_args)
for arg in iter_args:
emul_call+=str(arg)
emul_call+= " "
emul_call += "-pidfile %s " % qemu_pid
#Call QEMU
process = subprocess.Popen(emul_call, shell=True, preexec_fn=os.setsid)
for sig in [signal.SIGTERM, signal.SIGINT, signal.SIGHUP, signal.SIGQUIT]:
signal.signal(sig, kill_qemu_process)
process.wait()
#Close usvhost files
for fd in fd_list:
os.close(fd)
#Cleanup temporary files
if os.access(qemu_pid, os.F_OK):
os.remove(qemu_pid)
if __name__ == "__main__":
main()
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