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40 .Nd virtual kernel architecture
42 .Cd "platform vkernel64 # for 64 bit vkernels"
47 .Pa /var/vkernel/boot/kernel/kernel
50 .Op Fl e Ar name Ns = Ns Li value : Ns Ar name Ns = Ns Li value : Ns ...
52 .Op Fl I Ar interface Ns Op Ar :address1 Ns Oo Ar :address2 Oc Ns Oo Ar /netmask Oc Ns Oo Ar =mac Oc
55 .Op Fl n Ar numcpus Ns Op Ar :lbits Ns Oo Ar :cbits Oc
57 .Op Fl r Ar file Ns Op Ar :serno
61 architecture allows for running
65 The following options are available:
66 .Bl -tag -width ".Fl m Ar size"
68 Specify a readonly CD-ROM image
70 to be used by the kernel, with the first
81 option specified on the command line will be the boot disk.
82 The CD9660 filesystem is assumed when booting from this media.
83 .It Fl e Ar name Ns = Ns Li value : Ns Ar name Ns = Ns Li value : Ns ...
84 Specify an environment to be used by the kernel.
85 This option can be specified more than once.
87 Shows a list of available options, each with a short description.
89 Specify a memory image
91 to be used by the virtual kernel.
94 option is given, the kernel will generate a name of the form
95 .Pa /var/vkernel/memimg.XXXXXX ,
98 being replaced by a sequential number, e.g.\&
100 .It Fl I Ar interface Ns Op Ar :address1 Ns Oo Ar :address2 Oc Ns Oo Ar /netmask Oc Ns Oo Ar =MAC Oc
101 Create a virtual network device, with the first
111 argument is the name of a
113 device node or the path to a
118 path prefix does not have to be specified and will be automatically prepended
122 will pick the first unused
130 arguments are the IP addresses of the
141 interface is added to the specified
146 address is not assigned until the interface is brought up in the guest.
150 argument applies to all interfaces for which an address is specified.
154 argument is the MAC address of the
157 If not specified, a pseudo-random one will be generated.
159 When running multiple vkernels it is often more convenient to simply
162 socket and let vknetd deal with the tap and/or bridge.
163 An example of this would be
164 .Pa /var/run/vknet:0.0.0.0:10.2.0.2/16 .
166 Specify which, if any, real CPUs to lock virtual CPUs to.
170 .Cm map Ns Op Ns , Ns Ar startCPU ,
175 does not map virtual CPUs to real CPUs.
178 .Cm map Ns Op Ns , Ns Ar startCPU
179 maps each virtual CPU to a real CPU starting with real CPU 0 or
184 locks all virtual CPUs to the real CPU specified by
187 Specify the amount of memory to be used by the kernel in bytes,
195 Lowercase versions of
200 .It Fl n Ar numcpus Ns Op Ar :lbits Ns Oo Ar :cbits Oc
202 specifies the number of CPUs you wish to emulate.
203 Up to 16 CPUs are supported with 2 being the default unless otherwise
206 specifies the number of bits within APICID(=CPUID) needed for representing
208 Controls the number of threads/core (0bits - 1 thread, 1bit - 2 threads).
209 This parameter is optional (mandatory only if
213 specifies the number of bits within APICID(=CPUID) needed for representing
215 Controls the number of core/package (0bits - 1 core, 1bit - 2 cores).
216 This parameter is optional.
218 Specify a pidfile in which to store the process ID.
219 Scripts can use this file to locate the vkernel pid for the purpose of
220 shutting down or killing it.
222 The vkernel will hold a lock on the pidfile while running.
223 Scripts may test for the lock to determine if the pidfile is valid or
224 stale so as to avoid accidentally killing a random process.
225 Something like '/usr/bin/lockf -ks -t 0 pidfile echo -n' may be used
227 A non-zero exit code indicates that the pidfile represents a running
230 An error is issued and the vkernel exits if this file cannot be opened for
231 writing or if it is already locked by an active vkernel process.
232 .It Fl r Ar file Ns Op Ar :serno
233 Specify a R/W disk image
235 to be used by the kernel, with the first
242 A serial number for the virtual disk can be specified in
249 option specified on the command line will be the boot disk.
251 Boot into single-user mode.
253 Disables hardware pagetable for vkernel.
255 Enable writing to kernel memory and module loading.
256 By default, those are disabled for security reasons.
258 Turn on verbose booting.
261 A number of virtual device drivers exist to supplement the virtual kernel.
265 driver allows for up to 16
268 The root device will be
272 for further information on how to prepare a root image).
276 driver allows for up to 16 virtual CD-ROM devices.
277 Basically this is a read only
279 device with a block size of 2048.
280 .Ss Network interface
283 driver supports up to 16 virtual network interfaces which are associated with
288 device, the per-interface read only
291 .Va hw.vke Ns Em X Ns Va .tap_unit
292 holds the unit number of the associated
296 By default, half of the total mbuf clusters available is distributed equally
297 among all the vke devices up to 256.
298 This can be overridden with the tunable
299 .Va hw.vke.max_ringsize .
300 Take into account the number passed will be aligned to the lower power of two.
302 The virtual kernel only enables
306 while operating in regular console mode.
310 to the virtual kernel causes the virtual kernel to enter its internal
312 debugger and re-enable all other terminal signals.
315 to the virtual kernel triggers a clean shutdown by passing a
317 to the virtual kernel's
321 It is possible to directly gdb the virtual kernel's process.
322 It is recommended that you do a
323 .Ql handle SIGSEGV noprint
324 to ignore page faults processed by the virtual kernel itself and
325 .Ql handle SIGUSR1 noprint
326 to ignore signals used for simulating inter-processor interrupts.
328 To compile a vkernel with profiling support, the
330 variable needs to be used to pass
336 make -DNO_MODULES CONFIGARGS=-p buildkernel KERNCONF=VKERNEL64
339 .Bl -tag -width ".It Pa /sys/config/VKERNEL64" -compact
346 .It Pa /sys/config/VKERNEL64
350 configuration file, for
352 .Sh CONFIGURATION FILES
353 Your virtual kernel is a complete
355 system, but you might not want to run all the services a normal kernel runs.
356 Here is what a typical virtual kernel's
358 file looks like, with some additional possibilities commented out.
361 network_interfaces="lo0 vke0"
367 .Sh DISKLESS OPERATION
370 from a NFS root, a number of tunables need to be set:
371 .Bl -tag -width indent
373 IP address to be set in the vkernel interface.
374 .It Va boot.netif.netmask
375 Netmask for the IP to be set.
376 .It Va boot.netif.name
377 Network interface name inside the vkernel.
378 .It Va boot.nfsroot.server
381 .It Va boot.nfsroot.path
382 Host path where a world and distribution
383 targets are properly installed.
386 See an example on how to boot a diskless
392 A couple of steps are necessary in order to prepare the system to build and
393 run a virtual kernel.
394 .Ss Setting up the filesystem
397 architecture needs a number of files which reside in
399 Since these files tend to get rather big and the
401 partition is usually of limited size, we recommend the directory to be
404 partition with a link to it in
407 mkdir -p /home/var.vkernel/boot
408 ln -s /home/var.vkernel /var/vkernel
411 Next, a filesystem image to be used by the virtual kernel has to be
412 created and populated (assuming world has been built previously).
413 If the image is created on a UFS filesystem you might want to pre-zero it.
414 On a HAMMER filesystem you should just truncate-extend to the image size
415 as HAMMER does not re-use data blocks already present in the file.
417 vnconfig -c -S 2g -T vn0 /var/vkernel/rootimg.01
418 disklabel -r -w vn0s0 auto
419 disklabel -e vn0s0 # add `a' partition with fstype `4.2BSD'
421 mount /dev/vn0s0a /mnt
423 make installworld DESTDIR=/mnt
425 make distribution DESTDIR=/mnt
426 echo '/dev/vkd0s0a / ufs rw 1 1' >/mnt/etc/fstab
427 echo 'proc /proc procfs rw 0 0' >>/mnt/etc/fstab
434 entry with the following line and turn off all other gettys.
436 console "/usr/libexec/getty Pc" cons25 on secure
443 if you would like to automatically log in as root.
445 Then, unmount the disk.
450 .Ss Compiling the virtual kernel
451 In order to compile a virtual kernel use the
453 kernel configuration file residing in
455 (or a configuration file derived thereof):
458 make -DNO_MODULES buildkernel KERNCONF=VKERNEL64
459 make -DNO_MODULES installkernel KERNCONF=VKERNEL64 DESTDIR=/var/vkernel
461 .Ss Enabling virtual kernel operation
464 .Va vm.vkernel_enable ,
465 must be set to enable
469 sysctl vm.vkernel_enable=1
471 .Ss Configuring the network on the host system
472 In order to access a network interface of the host system from the
474 you must add the interface to a
476 device which will then be passed to the
482 ifconfig bridge0 create
483 ifconfig bridge0 addm re0 # assuming re0 is the host's interface
486 .Ss Running the kernel
487 Finally, the virtual kernel can be run:
490 \&./boot/kernel/kernel -m 64m -r rootimg.01 -I auto:bridge0
498 commands from inside a virtual kernel.
499 After doing a clean shutdown the
501 command will re-exec the virtual kernel binary while the other two will
502 cause the virtual kernel to exit.
503 .Ss Diskless operation
508 network configuration:
510 \&./boot/kernel/kernel -m 64m -m -i memimg.0000 -I /var/run/vknet
511 -e boot.netif.ip=172.1.0.4
512 -e boot.netif.netmask=255.255.0.0
513 -e boot.netif.name=vke0
514 -e boot.nfsroot.server=172.1.0.1
515 -e boot.nfsroot.path=/home/vkernel/vkdiskless
517 .Sh BUILDING THE WORLD UNDER A VKERNEL
518 The virtual kernel platform does not have all the header files expected
519 by a world build, so the easiest thing to do right now is to specify a
520 pc64 (in a 64 bit vkernel) target when building the world under a virtual
523 vkernel# make MACHINE_PLATFORM=pc64 buildworld
524 vkernel# make MACHINE_PLATFORM=pc64 installworld
540 .%A Aggelos Economopoulos
542 .%T "A Peek at the DragonFly Virtual Kernel"
545 Virtual kernels were introduced in
550 thought up and implemented the
552 architecture and wrote the
559 This manual page was written by