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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.
84 Disables hardware pagetable for
86 .It Fl e Ar name Ns = Ns Li value : Ns Ar name Ns = Ns Li value : Ns ...
87 Specify an environment to be used by the kernel.
88 This option can be specified more than once.
90 Shows a list of available options, each with a short description.
92 Specify a memory image
94 to be used by the virtual kernel.
97 option is given, the kernel will generate a name of the form
98 .Pa /var/vkernel/memimg.XXXXXX ,
101 being replaced by a sequential number, e.g.\&
103 .It Fl I Ar interface Ns Op Ar :address1 Ns Oo Ar :address2 Oc Ns Oo Ar /netmask Oc Ns Oo Ar =MAC Oc
104 Create a virtual network device, with the first
114 argument is the name of a
116 device node or the path to a
121 path prefix does not have to be specified and will be automatically prepended
125 will pick the first unused
133 arguments are the IP addresses of the
144 interface is added to the specified
149 address is not assigned until the interface is brought up in the guest.
153 argument applies to all interfaces for which an address is specified.
157 argument is the MAC address of the
160 If not specified, a pseudo-random one will be generated.
162 When running multiple vkernels it is often more convenient to simply
165 socket and let vknetd deal with the tap and/or bridge.
166 An example of this would be
167 .Pa /var/run/vknet:0.0.0.0:10.2.0.2/16 .
169 Specify which, if any, real CPUs to lock virtual CPUs to.
173 .Cm map Ns Op Ns , Ns Ar startCPU ,
178 does not map virtual CPUs to real CPUs.
181 .Cm map Ns Op Ns , Ns Ar startCPU
182 maps each virtual CPU to a real CPU starting with real CPU 0 or
187 locks all virtual CPUs to the real CPU specified by
190 Specify the amount of memory to be used by the kernel in bytes,
198 Lowercase versions of
203 .It Fl n Ar numcpus Ns Op Ar :lbits Ns Oo Ar :cbits Oc
205 specifies the number of CPUs you wish to emulate.
206 Up to 16 CPUs are supported with 2 being the default unless otherwise
209 specifies the number of bits within APICID(=CPUID) needed for representing
211 Controls the number of threads/core (0bits - 1 thread, 1bit - 2 threads).
212 This parameter is optional (mandatory only if
216 specifies the number of bits within APICID(=CPUID) needed for representing
218 Controls the number of core/package (0bits - 1 core, 1bit - 2 cores).
219 This parameter is optional.
221 Specify a pidfile in which to store the process ID.
222 Scripts can use this file to locate the vkernel pid for the purpose of
223 shutting down or killing it.
225 The vkernel will hold a lock on the pidfile while running.
226 Scripts may test for the lock to determine if the pidfile is valid or
227 stale so as to avoid accidentally killing a random process.
228 Something like '/usr/bin/lockf -ks -t 0 pidfile echo -n' may be used
230 A non-zero exit code indicates that the pidfile represents a running
233 An error is issued and the vkernel exits if this file cannot be opened for
234 writing or if it is already locked by an active vkernel process.
235 .It Fl r Ar file Ns Op Ar :serno
236 Specify a R/W disk image
238 to be used by the kernel, with the first
245 A serial number for the virtual disk can be specified in
252 option specified on the command line will be the boot disk.
254 Boot into single-user mode.
256 Enable writing to kernel memory and module loading.
257 By default, those are disabled for security reasons.
259 Turn on verbose booting.
262 A number of virtual device drivers exist to supplement the virtual kernel.
266 driver allows for up to 16
269 The root device will be
273 for further information on how to prepare a root image).
277 driver allows for up to 16 virtual CD-ROM devices.
278 Basically this is a read only
280 device with a block size of 2048.
281 .Ss Network interface
284 driver supports up to 16 virtual network interfaces which are associated with
289 device, the per-interface read only
292 .Va hw.vke Ns Em X Ns Va .tap_unit
293 holds the unit number of the associated
297 By default, half of the total mbuf clusters available is distributed equally
298 among all the vke devices up to 256.
299 This can be overridden with the tunable
300 .Va hw.vke.max_ringsize .
301 Take into account the number passed will be aligned to the lower power of two.
303 The virtual kernel only enables
307 while operating in regular console mode.
311 to the virtual kernel causes the virtual kernel to enter its internal
313 debugger and re-enable all other terminal signals.
316 to the virtual kernel triggers a clean shutdown by passing a
318 to the virtual kernel's
322 It is possible to directly gdb the virtual kernel's process.
323 It is recommended that you do a
324 .Ql handle SIGSEGV noprint
325 to ignore page faults processed by the virtual kernel itself and
326 .Ql handle SIGUSR1 noprint
327 to ignore signals used for simulating inter-processor interrupts.
329 To compile a vkernel with profiling support, the
331 variable needs to be used to pass
337 make -DNO_MODULES CONFIGARGS=-p buildkernel KERNCONF=VKERNEL64
340 .Bl -tag -width ".It Pa /sys/config/VKERNEL64" -compact
347 .It Pa /sys/config/VKERNEL64
351 configuration file, for
353 .Sh CONFIGURATION FILES
354 Your virtual kernel is a complete
356 system, but you might not want to run all the services a normal kernel runs.
357 Here is what a typical virtual kernel's
359 file looks like, with some additional possibilities commented out.
362 network_interfaces="lo0 vke0"
368 .Sh DISKLESS OPERATION
371 from a NFS root, a number of tunables need to be set:
372 .Bl -tag -width indent
374 IP address to be set in the vkernel interface.
375 .It Va boot.netif.netmask
376 Netmask for the IP to be set.
377 .It Va boot.netif.name
378 Network interface name inside the vkernel.
379 .It Va boot.nfsroot.server
382 .It Va boot.nfsroot.path
383 Host path where a world and distribution
384 targets are properly installed.
387 See an example on how to boot a diskless
393 A couple of steps are necessary in order to prepare the system to build and
394 run a virtual kernel.
395 .Ss Setting up the filesystem
398 architecture needs a number of files which reside in
400 Since these files tend to get rather big and the
402 partition is usually of limited size, we recommend the directory to be
405 partition with a link to it in
408 mkdir -p /home/var.vkernel/boot
409 ln -s /home/var.vkernel /var/vkernel
412 Next, a filesystem image to be used by the virtual kernel has to be
413 created and populated (assuming world has been built previously).
414 If the image is created on a UFS filesystem you might want to pre-zero it.
415 On a HAMMER filesystem you should just truncate-extend to the image size
416 as HAMMER does not re-use data blocks already present in the file.
418 vnconfig -c -S 2g -T vn0 /var/vkernel/rootimg.01
419 disklabel -r -w vn0s0 auto
420 disklabel -e vn0s0 # add `a' partition with fstype `4.2BSD'
422 mount /dev/vn0s0a /mnt
424 make installworld DESTDIR=/mnt
426 make distribution DESTDIR=/mnt
427 echo '/dev/vkd0s0a / ufs rw 1 1' >/mnt/etc/fstab
428 echo 'proc /proc procfs rw 0 0' >>/mnt/etc/fstab
435 entry with the following line and turn off all other gettys.
437 console "/usr/libexec/getty Pc" cons25 on secure
444 if you would like to automatically log in as root.
446 Then, unmount the disk.
451 .Ss Compiling the virtual kernel
452 In order to compile a virtual kernel use the
454 kernel configuration file residing in
456 (or a configuration file derived thereof):
459 make -DNO_MODULES buildkernel KERNCONF=VKERNEL64
460 make -DNO_MODULES installkernel KERNCONF=VKERNEL64 DESTDIR=/var/vkernel
462 .Ss Enabling virtual kernel operation
465 .Va vm.vkernel_enable ,
466 must be set to enable
470 sysctl vm.vkernel_enable=1
472 .Ss Configuring the network on the host system
473 In order to access a network interface of the host system from the
475 you must add the interface to a
477 device which will then be passed to the
483 ifconfig bridge0 create
484 ifconfig bridge0 addm re0 # assuming re0 is the host's interface
487 .Ss Running the kernel
488 Finally, the virtual kernel can be run:
491 \&./boot/kernel/kernel -m 64m -r rootimg.01 -I auto:bridge0
499 commands from inside a virtual kernel.
500 After doing a clean shutdown the
502 command will re-exec the virtual kernel binary while the other two will
503 cause the virtual kernel to exit.
504 .Ss Diskless operation
509 network configuration:
511 \&./boot/kernel/kernel -m 64m -m -i memimg.0000 -I /var/run/vknet
512 -e boot.netif.ip=172.1.0.4
513 -e boot.netif.netmask=255.255.0.0
514 -e boot.netif.name=vke0
515 -e boot.nfsroot.server=172.1.0.1
516 -e boot.nfsroot.path=/home/vkernel/vkdiskless
518 .Sh BUILDING THE WORLD UNDER A VKERNEL
519 The virtual kernel platform does not have all the header files expected
520 by a world build, so the easiest thing to do right now is to specify a
521 pc64 (in a 64 bit vkernel) target when building the world under a virtual
524 vkernel# make MACHINE_PLATFORM=pc64 buildworld
525 vkernel# make MACHINE_PLATFORM=pc64 installworld
541 .%A Aggelos Economopoulos
543 .%T "A Peek at the DragonFly Virtual Kernel"
546 Virtual kernels were introduced in
551 thought up and implemented the
553 architecture and wrote the
560 This manual page was written by