summaryrefslogtreecommitdiffstats
path: root/lib/librte_vhost/libvirt/qemu-wrap.py
blob: e6a2cc9d03754fc14c148aaa5f5fe062b6513896 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
#!/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()