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32 .\" $DragonFly: src/share/man/man7/vkernel.7,v 1.20 2007/06/19 17:25:46 dillon Exp $
41 .Nd virtual kernel architecture
43 .Cd "platform vkernel"
47 .Pa /usr/obj/usr/src/sys/VKERNEL/kernel.debug
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
59 architecture allows for running
63 The following options are available:
64 .Bl -tag -width ".Fl m Ar size"
66 Specify a readonly CD-ROM image
68 to be used by the kernel, with the first
78 option specified on the command line will be the boot disk.
79 The CD9660 filesystem is assumed when booting from this media.
80 .It Fl e Ar name Ns = Ns Li value : Ns Ar name Ns = Ns Li value : Ns ...
81 Specify an environment to be used by the kernel.
83 Specify a memory image
85 to be used by the virtual kernel.
88 option is given, the kernel will generate a name of the form
89 .Pa /var/vkernel/memimg.XXXXXX ,
92 being replaced by a sequential number, e.g.\&
94 .It Fl I Ar interface Ns Op Ar :address1 Ns Oo Ar :address2 Oc Ns Oo Ar /netmask Oc
95 Create a virtual network device, with the first
105 argument is the name of a
110 path prefix does not have to be specified and will be automatically prepended.
113 will pick the first unused
121 arguments are the IP addresses of the
132 interface is added to the specified
138 argument applies to all interfaces for which an address is specified.
140 Specify the amount of memory to be used by the kernel in bytes,
148 Lowercase versions of
154 Specify a file in which to store the process ID.
155 A warning is issued if this file cannot be opened for writing.
157 Specify a R/W disk image
159 to be used by the kernel, with the first
169 option specified on the command line will be the boot disk.
171 Boot into single-user mode.
173 Enable writing to kernel memory and module loading.
174 By default, those are disabled for security reasons.
176 Turn on verbose booting.
179 A number of virtual device drivers exist to supplement the virtual kernel.
180 Their names start with
185 driver allows for up to 16
188 The root device will be
192 for further information on how to prepare a root image).
193 .Ss Network interface
196 driver supports up to 16 virtual network interfaces which are associated with
201 device, the per-interface read only
204 .Va hw.vke Ns Em X Ns Va .tap_unit
205 holds the unit number of the associated
209 The virtual kernel only enables
213 while operating in regular console mode.
217 to the virtual kernel causes the virtual kernel to enter its internal
219 debugger and re-enable all other terminal signals.
222 to the virtual kernel triggers a clean shutdown by passing a
224 to the virtual kernel's
228 It is possible to directly gdb the virtual kernel's process.
229 It is recommended that you do a
230 .Ql handle SIGSEGV noprint
231 to ignore page faults processed by the virtual kernel itself.
233 A couple of steps are necessary in order to prepare the system to build and
234 run a virtual kernel.
235 .Ss Setting up the filesystem
238 architecture needs a number of files which reside in
240 Since these files tend to get rather big and the
242 partition is usually of limited size, we recommend the directory to be
245 partition with a link to it in
248 mkdir /home/var.vkernel
249 ln -s /home/var.vkernel /var/vkernel
252 Next, a filesystem image to be used by the virtual kernel has to be
253 created and populated (assuming world has been built previously):
255 dd if=/dev/zero of=/var/vkernel/rootimg.01 bs=1m count=2048
256 vnconfig -c -s labels vn0 /var/vkernel/rootimg.01
257 disklabel -r -w vn0s0 auto
258 disklabel -e vn0s0 # edit the label to create a vn0s0a partition
260 mount /dev/vn0s0a /mnt
262 make installworld DESTDIR=/mnt
264 make distribution DESTDIR=/mnt
265 echo '/dev/vkd0a / ufs rw 1 1' >/mnt/etc/fstab
272 entry with the following line and turn off all other gettys.
274 console "/usr/libexec/getty Pc" cons25 on secure
277 Then, unmount the disk.
282 .Ss Compiling the virtual kernel
283 In order to compile a virtual kernel use the
285 kernel configuration file residing in
286 .Pa /usr/src/sys/config
287 (or a configuration file derived thereof):
290 make -DNO_MODULES buildkernel KERNCONF=VKERNEL
292 .Ss Enabling virtual kernel operation
295 .Va vm.vkernel_enable ,
296 must be set to enable
300 sysctl vm.vkernel_enable=1
302 .Ss Configuring the network on the host system
303 In order to access a network interface of the host system from the
305 you must add the interface to a
307 device which will then be passed to the
313 ifconfig bridge0 create
314 ifconfig bridge0 addm re0 # assuming re0 is the host's interface
317 .Ss Running the kernel
318 Finally, the virtual kernel can be run:
320 cd /usr/obj/usr/src/sys/VKERNEL
321 \&./kernel.debug -m 64m -r /var/vkernel/rootimg.01 -I auto:bridge0
326 command can be used to stop a virtual kernel.
336 Virtual kernels were introduced in
341 thought up and implemented the
343 architecture and wrote the
350 This manual page was written by