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40 .Nd virtual kernel architecture
42 .Cd "platform vkernel # for 32 bit vkernels"
43 .Cd "platform vkernel64 # for 64 bit vkernels"
48 .Pa /var/vkernel/boot/kernel/kernel
51 .Op Fl e Ar name Ns = Ns Li value : Ns Ar name Ns = Ns Li value : Ns ...
53 .Op Fl I Ar interface Ns Op Ar :address1 Ns Oo Ar :address2 Oc Ns Oo Ar /netmask Oc
62 architecture allows for running
66 The following options are available:
67 .Bl -tag -width ".Fl m Ar size"
69 Specify a readonly CD-ROM image
71 to be used by the kernel, with the first
82 option specified on the command line will be the boot disk.
83 The CD9660 filesystem is assumed when booting from this media.
84 .It Fl e Ar name Ns = Ns Li value : Ns Ar name Ns = Ns Li value : Ns ...
85 Specify an environment to be used by the kernel.
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
101 Create a virtual network device, with the first
111 argument is the name of a
116 path prefix does not have to be specified and will be automatically prepended.
119 will pick the first unused
127 arguments are the IP addresses of the
138 interface is added to the specified
143 address is not assigned until the interface is brought up in the guest.
147 argument applies to all interfaces for which an address is specified.
149 Specify which, if any, real CPUs to lock virtual CPUs to.
153 .Cm map Ns Op Ns , Ns Ar startCPU ,
158 does not map virtual CPUs to real CPUs.
161 .Cm map Ns Op Ns , Ns Ar startCPU
162 maps each virtual CPU to a real CPU starting with real CPU 0 or
167 locks all virtual CPUs to the real CPU specified by
170 Specify the amount of memory to be used by the kernel in bytes,
178 Lowercase versions of
184 Specify the number of CPUs you wish to emulate.
185 Up to 16 CPUs are supported.
186 The virtual kernel must be built with
188 to use this option and will default to 2 CPUs unless otherwise specified.
190 Specify a file in which to store the process ID.
191 A warning is issued if this file cannot be opened for writing.
193 Specify a R/W disk image
195 to be used by the kernel, with the first
206 option specified on the command line will be the boot disk.
208 Boot into single-user mode.
210 Enable writing to kernel memory and module loading.
211 By default, those are disabled for security reasons.
213 Turn on verbose booting.
216 A number of virtual device drivers exist to supplement the virtual kernel.
220 driver allows for up to 16
223 The root device will be
227 for further information on how to prepare a root image).
231 driver allows for up to 16 virtual CD-ROM devices.
232 Basically this is a read only
234 device with a block size of 2048.
235 .Ss Network interface
238 driver supports up to 16 virtual network interfaces which are associated with
243 device, the per-interface read only
246 .Va hw.vke Ns Em X Ns Va .tap_unit
247 holds the unit number of the associated
251 The virtual kernel only enables
255 while operating in regular console mode.
259 to the virtual kernel causes the virtual kernel to enter its internal
261 debugger and re-enable all other terminal signals.
264 to the virtual kernel triggers a clean shutdown by passing a
266 to the virtual kernel's
270 It is possible to directly gdb the virtual kernel's process.
271 It is recommended that you do a
272 .Ql handle SIGSEGV noprint
273 to ignore page faults processed by the virtual kernel itself and
274 .Ql handle SIGUSR1 noprint
275 to ignore signals used for simulating inter-processor interrupts (SMP build
278 .Bl -tag -width ".It Pa /sys/config/VKERNEL" -compact
279 .It Pa /sys/config/VKERNEL
282 configuration file, for
285 .Sh CONFIGURATION FILES
286 Your virtual kernel is a complete
288 system, but you might not want to run all the services a normal kernel runs.
289 Here is what a typical virtual kernel's
291 file looks like, with some additional possibilities commented out.
294 network_interfaces="lo0 vke0"
301 A couple of steps are necessary in order to prepare the system to build and
302 run a virtual kernel.
303 .Ss Setting up the filesystem
306 architecture needs a number of files which reside in
308 Since these files tend to get rather big and the
310 partition is usually of limited size, we recommend the directory to be
313 partition with a link to it in
316 mkdir -p /home/var.vkernel/boot
317 ln -s /home/var.vkernel /var/vkernel
320 Next, a filesystem image to be used by the virtual kernel has to be
321 created and populated (assuming world has been built previously).
322 If the image is created on a UFS filesystem you might want to pre-zero it.
323 On a HAMMER filesystem you should just truncate-extend to the image size
324 as HAMMER does not re-use data blocks already present in the file.
326 vnconfig -c -S 2g -T vn0 /var/vkernel/rootimg.01
327 disklabel -r -w vn0s0 auto
328 disklabel -e vn0s0 # add `a' partition with fstype `4.2BSD'
330 mount /dev/vn0s0a /mnt
332 make installworld DESTDIR=/mnt
334 make distribution DESTDIR=/mnt
335 echo '/dev/vkd0s0a / ufs rw 1 1' >/mnt/etc/fstab
336 echo 'proc /proc procfs rw 0 0' >>/mnt/etc/fstab
343 entry with the following line and turn off all other gettys.
345 console "/usr/libexec/getty Pc" cons25 on secure
352 if you would like to automatically log in as root.
354 Then, unmount the disk.
359 .Ss Compiling the virtual kernel
360 In order to compile a virtual kernel use the
362 kernel configuration file residing in
364 (or a configuration file derived thereof):
367 make -DNO_MODULES buildkernel KERNCONF=VKERNEL
368 make -DNO_MODULES installkernel KERNCONF=VKERNEL DESTDIR=/var/vkernel
370 .Ss Enabling virtual kernel operation
373 .Va vm.vkernel_enable ,
374 must be set to enable
378 sysctl vm.vkernel_enable=1
380 .Ss Configuring the network on the host system
381 In order to access a network interface of the host system from the
383 you must add the interface to a
385 device which will then be passed to the
391 ifconfig bridge0 create
392 ifconfig bridge0 addm re0 # assuming re0 is the host's interface
395 .Ss Running the kernel
396 Finally, the virtual kernel can be run:
399 \&./boot/kernel/kernel -m 64m -r rootimg.01 -I auto:bridge0
407 commands from inside a virtual kernel.
408 After doing a clean shutdown the
410 command will re-exec the virtual kernel binary while the other two will
411 cause the virtual kernel to exit.
412 .Sh BUILDING THE WORLD UNDER A VKERNEL
413 The virtual kernel platform does not have all the header files expected
414 by a world build, so the easiest thing to do right now is to specify a
415 pc32 (in a 32 bit vkernel) or pc64 (in a 64 bit vkernel) target when
416 building the world under a virtual kernel, like this:
418 vkernel# make MACHINE_PLATFORM=pc32 buildworld
419 vkernel# make MACHINE_PLATFORM=pc32 installworld
433 .%A Aggelos Economopoulos
435 .%T "A Peek at the DragonFly Virtual Kernel"
438 Virtual kernels were introduced in
443 thought up and implemented the
445 architecture and wrote the
452 This manual page was written by