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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
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 Specify a memory image
89 to be used by the virtual kernel.
92 option is given, the kernel will generate a name of the form
93 .Pa /var/vkernel/memimg.XXXXXX ,
96 being replaced by a sequential number, e.g.\&
98 .It Fl I Ar interface Ns Op Ar :address1 Ns Oo Ar :address2 Oc Ns Oo Ar /netmask Oc
99 Create a virtual network device, with the first
109 argument is the name of a
114 path prefix does not have to be specified and will be automatically prepended.
117 will pick the first unused
125 arguments are the IP addresses of the
136 interface is added to the specified
141 address is not assigned until the interface is brought up in the guest.
145 argument applies to all interfaces for which an address is specified.
147 Specify which, if any, real CPUs to lock virtual CPUs to.
151 .Cm map Ns Op Ns , Ns Ar startCPU ,
156 does not map virtual CPUs to real CPUs.
159 .Cm map Ns Op Ns , Ns Ar startCPU
160 maps each virtual CPU to a real CPU starting with real CPU 0 or
165 locks all virtual CPUs to the real CPU specified by
168 Specify the amount of memory to be used by the kernel in bytes,
176 Lowercase versions of
182 Specify the number of CPUs you wish to emulate.
183 Up to 16 CPUs are supported.
184 The virtual kernel must be built with
186 to use this option and will default to 2 CPUs unless otherwise specified.
188 Specify a file in which to store the process ID.
189 A warning is issued if this file cannot be opened for writing.
191 Specify a R/W disk image
193 to be used by the kernel, with the first
204 option specified on the command line will be the boot disk.
206 Boot into single-user mode.
208 Enable writing to kernel memory and module loading.
209 By default, those are disabled for security reasons.
211 Turn on verbose booting.
214 A number of virtual device drivers exist to supplement the virtual kernel.
218 driver allows for up to 16
221 The root device will be
225 for further information on how to prepare a root image).
229 driver allows for up to 16 virtual CD-ROM devices.
230 Basically this is a read only
232 device with a block size of 2048.
233 .Ss Network interface
236 driver supports up to 16 virtual network interfaces which are associated with
241 device, the per-interface read only
244 .Va hw.vke Ns Em X Ns Va .tap_unit
245 holds the unit number of the associated
249 The virtual kernel only enables
253 while operating in regular console mode.
257 to the virtual kernel causes the virtual kernel to enter its internal
259 debugger and re-enable all other terminal signals.
262 to the virtual kernel triggers a clean shutdown by passing a
264 to the virtual kernel's
268 It is possible to directly gdb the virtual kernel's process.
269 It is recommended that you do a
270 .Ql handle SIGSEGV noprint
271 to ignore page faults processed by the virtual kernel itself and
272 .Ql handle SIGUSR1 noprint
273 to ignore signals used for simulating inter-processor interrupts (SMP build
276 .Bl -tag -width ".It Pa /sys/config/VKERNEL" -compact
277 .It Pa /sys/config/VKERNEL
280 configuration file, for
283 .Sh CONFIGURATION FILES
284 Your virtual kernel is a complete
286 system, but you might not want to run all the services a normal kernel runs.
287 Here is what a typical virtual kernel's
289 file looks like, with some additional possibilities commented out.
292 network_interfaces="lo0 vke0"
299 A couple of steps are necessary in order to prepare the system to build and
300 run a virtual kernel.
301 .Ss Setting up the filesystem
304 architecture needs a number of files which reside in
306 Since these files tend to get rather big and the
308 partition is usually of limited size, we recommend the directory to be
311 partition with a link to it in
314 mkdir -p /home/var.vkernel/boot
315 ln -s /home/var.vkernel /var/vkernel
318 Next, a filesystem image to be used by the virtual kernel has to be
319 created and populated (assuming world has been built previously).
320 If the image is created on a UFS filesystem you might want to pre-zero it.
321 On a HAMMER filesystem you should just truncate-extend to the image size
322 as HAMMER does not re-use data blocks already present in the file.
324 vnconfig -c -S 2g -T vn0 /var/vkernel/rootimg.01
325 disklabel -r -w vn0s0 auto
326 disklabel -e vn0s0 # add `a' partition with fstype `4.2BSD'
328 mount /dev/vn0s0a /mnt
330 make installworld DESTDIR=/mnt
332 make distribution DESTDIR=/mnt
333 echo '/dev/vkd0s0a / ufs rw 1 1' >/mnt/etc/fstab
334 echo 'proc /proc procfs rw 0 0' >>/mnt/etc/fstab
341 entry with the following line and turn off all other gettys.
343 console "/usr/libexec/getty Pc" cons25 on secure
350 if you would like to automatically log in as root.
352 Then, unmount the disk.
357 .Ss Compiling the virtual kernel
358 In order to compile a virtual kernel use the
360 kernel configuration file residing in
362 (or a configuration file derived thereof):
365 make -DNO_MODULES buildkernel KERNCONF=VKERNEL
366 make -DNO_MODULES installkernel KERNCONF=VKERNEL DESTDIR=/var/vkernel
368 .Ss Enabling virtual kernel operation
371 .Va vm.vkernel_enable ,
372 must be set to enable
376 sysctl vm.vkernel_enable=1
378 .Ss Configuring the network on the host system
379 In order to access a network interface of the host system from the
381 you must add the interface to a
383 device which will then be passed to the
389 ifconfig bridge0 create
390 ifconfig bridge0 addm re0 # assuming re0 is the host's interface
393 .Ss Running the kernel
394 Finally, the virtual kernel can be run:
397 \&./boot/kernel -m 64m -r rootimg.01 -I auto:bridge0
405 commands from inside a virtual kernel.
406 After doing a clean shutdown the
408 command will re-exec the virtual kernel binary while the other two will
409 cause the virtual kernel to exit.
410 .Sh BUILDING THE WORLD UNDER A VKERNEL
411 The virtual kernel platform does not have all the header files expected
412 by a world build, so the easiest thing to do right now is to specify a
413 pc32 (in a 32 bit vkernel) or pc64 (in a 64 bit vkernel) target when
414 building the world under a virtual kernel, like this:
416 vkernel# make MACHINE_PLATFORM=pc32 buildworld
417 vkernel# make MACHINE_PLATFORM=pc32 installworld
431 .%A Aggelos Economopoulos
433 .%T "A Peek at the DragonFly Virtual Kernel"
436 Virtual kernels were introduced in
441 thought up and implemented the
443 architecture and wrote the
450 This manual page was written by