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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
210 specifies the number of bits within APICID(=CPUID) needed for representing
212 Controls the number of threads/core (0 bits - 1 thread, 1 bit - 2 threads).
213 This parameter is optional (mandatory only if
218 specifies the number of bits within APICID(=CPUID) needed for representing
220 Controls the number of core/package (0 bits - 1 core, 1 bit - 2 cores).
221 This parameter is optional.
223 Specify a pidfile in which to store the process ID.
224 Scripts can use this file to locate the vkernel pid for the purpose of
225 shutting down or killing it.
227 The vkernel will hold a lock on the pidfile while running.
228 Scripts may test for the lock to determine if the pidfile is valid or
229 stale so as to avoid accidentally killing a random process.
230 Something like '/usr/bin/lockf -ks -t 0 pidfile echo -n' may be used
232 A non-zero exit code indicates that the pidfile represents a running
235 An error is issued and the vkernel exits if this file cannot be opened for
236 writing or if it is already locked by an active vkernel process.
237 .It Fl r Ar file Ns Op Ar :serno
238 Specify a R/W disk image
240 to be used by the kernel, with the first
247 A serial number for the virtual disk can be specified in
254 option specified on the command line will be the boot disk.
256 Boot into single-user mode.
258 Enable writing to kernel memory and module loading.
259 By default, those are disabled for security reasons.
261 Turn on verbose booting.
264 A number of virtual device drivers exist to supplement the virtual kernel.
268 driver allows for up to 16
271 The root device will be
275 for further information on how to prepare a root image).
279 driver allows for up to 16 virtual CD-ROM devices.
280 Basically this is a read only
282 device with a block size of 2048.
283 .Ss Network interface
286 driver supports up to 16 virtual network interfaces which are associated with
291 device, the per-interface read only
294 .Va hw.vke Ns Em X Ns Va .tap_unit
295 holds the unit number of the associated
299 By default, half of the total mbuf clusters available is distributed equally
300 among all the vke devices up to 256.
301 This can be overridden with the tunable
302 .Va hw.vke.max_ringsize .
303 Take into account the number passed will be aligned to the lower power of two.
305 The virtual kernel only enables
309 while operating in regular console mode.
313 to the virtual kernel causes the virtual kernel to enter its internal
315 debugger and re-enable all other terminal signals.
318 to the virtual kernel triggers a clean shutdown by passing a
320 to the virtual kernel's
324 It is possible to directly gdb the virtual kernel's process.
325 It is recommended that you do a
326 .Ql handle SIGSEGV noprint
327 to ignore page faults processed by the virtual kernel itself and
328 .Ql handle SIGUSR1 noprint
329 to ignore signals used for simulating inter-processor interrupts.
331 To compile a vkernel with profiling support, the
333 variable needs to be used to pass
339 make -DNO_MODULES CONFIGARGS=-p buildkernel KERNCONF=VKERNEL64
342 .Bl -tag -width ".It Pa /sys/config/VKERNEL64" -compact
349 .It Pa /sys/config/VKERNEL64
353 configuration file, for
355 .Sh CONFIGURATION FILES
356 Your virtual kernel is a complete
358 system, but you might not want to run all the services a normal kernel runs.
359 Here is what a typical virtual kernel's
361 file looks like, with some additional possibilities commented out.
364 network_interfaces="lo0 vke0"
370 .Sh DISKLESS OPERATION
373 from a NFS root, a number of tunables need to be set:
374 .Bl -tag -width indent
376 IP address to be set in the vkernel interface.
377 .It Va boot.netif.netmask
378 Netmask for the IP to be set.
379 .It Va boot.netif.name
380 Network interface name inside the vkernel.
381 .It Va boot.nfsroot.server
384 .It Va boot.nfsroot.path
385 Host path where a world and distribution
386 targets are properly installed.
389 See an example on how to boot a diskless
395 A couple of steps are necessary in order to prepare the system to build and
396 run a virtual kernel.
397 .Ss Setting up the filesystem
400 architecture needs a number of files which reside in
402 Since these files tend to get rather big and the
404 partition is usually of limited size, we recommend the directory to be
407 partition with a link to it in
410 mkdir -p /home/var.vkernel/boot
411 ln -s /home/var.vkernel /var/vkernel
414 Next, a filesystem image to be used by the virtual kernel has to be
415 created and populated (assuming world has been built previously).
416 If the image is created on a UFS filesystem you might want to pre-zero it.
417 On a HAMMER filesystem you should just truncate-extend to the image size
418 as HAMMER does not re-use data blocks already present in the file.
420 vnconfig -c -S 2g -T vn0 /var/vkernel/rootimg.01
421 disklabel -r -w vn0s0 auto
422 disklabel -e vn0s0 # add `a' partition with fstype `4.2BSD'
424 mount /dev/vn0s0a /mnt
426 make installworld DESTDIR=/mnt
428 make distribution DESTDIR=/mnt
429 echo '/dev/vkd0s0a / ufs rw 1 1' >/mnt/etc/fstab
430 echo 'proc /proc procfs rw 0 0' >>/mnt/etc/fstab
437 entry with the following line and turn off all other gettys.
439 console "/usr/libexec/getty Pc" cons25 on secure
446 if you would like to automatically log in as root.
448 Then, unmount the disk.
453 .Ss Compiling the virtual kernel
454 In order to compile a virtual kernel use the
456 kernel configuration file residing in
458 (or a configuration file derived thereof):
461 make -DNO_MODULES buildkernel KERNCONF=VKERNEL64
462 make -DNO_MODULES installkernel KERNCONF=VKERNEL64 DESTDIR=/var/vkernel
464 .Ss Enabling virtual kernel operation
467 .Va vm.vkernel_enable ,
468 must be set to enable
472 sysctl vm.vkernel_enable=1
474 .Ss Configuring the network on the host system
475 In order to access a network interface of the host system from the
477 you must add the interface to a
479 device which will then be passed to the
485 ifconfig bridge0 create
486 ifconfig bridge0 addm re0 # assuming re0 is the host's interface
489 .Ss Running the kernel
490 Finally, the virtual kernel can be run:
493 \&./boot/kernel/kernel -m 64m -r rootimg.01 -I auto:bridge0
501 commands from inside a virtual kernel.
502 After doing a clean shutdown the
504 command will re-exec the virtual kernel binary while the other two will
505 cause the virtual kernel to exit.
506 .Ss Diskless operation
511 network configuration:
513 \&./boot/kernel/kernel -m 64m -m -i memimg.0000 -I /var/run/vknet
514 -e boot.netif.ip=172.1.0.4
515 -e boot.netif.netmask=255.255.0.0
516 -e boot.netif.name=vke0
517 -e boot.nfsroot.server=172.1.0.1
518 -e boot.nfsroot.path=/home/vkernel/vkdiskless
520 .Sh BUILDING THE WORLD UNDER A VKERNEL
521 The virtual kernel platform does not have all the header files expected
522 by a world build, so the easiest thing to do right now is to specify a
523 pc64 (in a 64 bit vkernel) target when building the world under a virtual
526 vkernel# make MACHINE_PLATFORM=pc64 buildworld
527 vkernel# make MACHINE_PLATFORM=pc64 installworld
543 .%A Aggelos Economopoulos
545 .%T "A Peek at the DragonFly Virtual Kernel"
548 Virtual kernels were introduced in
553 thought up and implemented the
555 architecture and wrote the
562 This manual page was written by