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32 .\" $DragonFly: src/share/man/man7/vkernel.7,v 1.41.2.1 2008/07/18 00:05:26 thomas Exp $
42 .Nd virtual kernel architecture
44 .Cd "platform vkernel"
49 .Pa /var/vkernel/kernel
52 .Op Fl e Ar name Ns = Ns Li value : Ns Ar name Ns = Ns Li value : Ns ...
54 .Op Fl I Ar interface Ns Op Ar :address1 Ns Oo Ar :address2 Oc Ns Oo Ar /netmask Oc
63 architecture allows for running
67 The following options are available:
68 .Bl -tag -width ".Fl m Ar size"
70 Specify a readonly CD-ROM image
72 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
203 option specified on the command line will be the boot disk.
205 Boot into single-user mode.
207 Enable writing to kernel memory and module loading.
208 By default, those are disabled for security reasons.
210 Turn on verbose booting.
213 A number of virtual device drivers exist to supplement the virtual kernel.
217 driver allows for up to 16
220 The root device will be
224 for further information on how to prepare a root image).
228 driver allows for up to 16 virtual CD-ROM devices.
229 Basically this is a read only
231 device with a block size of 2048.
232 .Ss Network interface
235 driver supports up to 16 virtual network interfaces which are associated with
240 device, the per-interface read only
243 .Va hw.vke Ns Em X Ns Va .tap_unit
244 holds the unit number of the associated
248 The virtual kernel only enables
252 while operating in regular console mode.
256 to the virtual kernel causes the virtual kernel to enter its internal
258 debugger and re-enable all other terminal signals.
261 to the virtual kernel triggers a clean shutdown by passing a
263 to the virtual kernel's
267 It is possible to directly gdb the virtual kernel's process.
268 It is recommended that you do a
269 .Ql handle SIGSEGV noprint
270 to ignore page faults processed by the virtual kernel itself and
271 .Ql handle SIGUSR1 noprint
272 to ignore signals used for simulating inter-processor interrupts (SMP build
275 .Bl -tag -width ".It Pa /sys/config/VKERNEL" -compact
276 .It Pa /sys/config/VKERNEL
279 configuration file, for
283 A couple of steps are necessary in order to prepare the system to build and
284 run a virtual kernel.
285 .Ss Setting up the filesystem
288 architecture needs a number of files which reside in
290 Since these files tend to get rather big and the
292 partition is usually of limited size, we recommend the directory to be
295 partition with a link to it in
298 mkdir /home/var.vkernel
299 ln -s /home/var.vkernel /var/vkernel
302 Next, a filesystem image to be used by the virtual kernel has to be
303 created and populated (assuming world has been built previously):
305 dd if=/dev/zero of=/var/vkernel/rootimg.01 bs=1m count=2048
306 vnconfig -c -s labels vn0 /var/vkernel/rootimg.01
307 disklabel -r -w vn0s0 auto
308 disklabel -e vn0s0 # edit the label to create a vn0s0a partition
310 mount /dev/vn0s0a /mnt
312 make installworld DESTDIR=/mnt
314 make distribution DESTDIR=/mnt
315 echo '/dev/vkd0s0a / ufs rw 1 1' >/mnt/etc/fstab
316 echo 'proc /proc procfs rw 0 0' >>/mnt/etc/fstab
323 entry with the following line and turn off all other gettys.
325 console "/usr/libexec/getty Pc" cons25 on secure
328 Then, unmount the disk.
333 .Ss Compiling the virtual kernel
334 In order to compile a virtual kernel use the
336 kernel configuration file residing in
338 (or a configuration file derived thereof):
341 make -DNO_MODULES buildkernel KERNCONF=VKERNEL
342 make -DNO_MODULES installkernel KERNCONF=VKERNEL DESTDIR=/var/vkernel
344 .Ss Enabling virtual kernel operation
347 .Va vm.vkernel_enable ,
348 must be set to enable
352 sysctl vm.vkernel_enable=1
354 .Ss Configuring the network on the host system
355 In order to access a network interface of the host system from the
357 you must add the interface to a
359 device which will then be passed to the
365 ifconfig bridge0 create
366 ifconfig bridge0 addm re0 # assuming re0 is the host's interface
369 .Ss Running the kernel
370 Finally, the virtual kernel can be run:
373 \&./kernel -m 64m -r rootimg.01 -I auto:bridge0
381 commands from inside a virtual kernel.
382 After doing a clean shutdown the
384 command will re-exec the virtual kernel binary while the other two will
385 cause the virtual kernel to exit.
386 .Sh BUILDING THE WORLD UNDER A VKERNEL
387 The virtual kernel platform does not have all the header files expected
388 by a world build, so the easiest thing to do right now is to specify a
389 pc32 target when building the world under a virtual kernel, like this:
391 vkernel# make MACHINE_PLATFORM=pc32 buildworld
392 vkernel# make MACHINE_PLATFORM=pc32 installworld
394 .Sh CONFIGURATION FILES
395 Your virtual kernel is a complete
397 system, but you might not want to run all the services a normal kernel runs.
398 Here is what a typical virtual kernel's
400 file looks like, with some additional possibilities commented out.
403 network_interfaces="lo0 vke0"
421 .%A Aggelos Economopoulos
423 .%T "A Peek at the DragonFly Virtual Kernel"
426 Virtual kernels were introduced in
431 thought up and implemented the
433 architecture and wrote the
440 This manual page was written by