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32 .\" $DragonFly: src/share/man/man7/vkernel.7,v 1.29 2007/08/18 08:46:32 swildner Exp $
42 .Nd virtual kernel architecture
44 .Cd "platform vkernel"
49 .Pa /usr/obj/usr/src/sys/VKERNEL/kernel.debug
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
142 argument applies to all interfaces for which an address is specified.
144 Specify which, if any, real CPUs to lock virtual CPUs to.
148 .Cm map Ns Op Ns , Ns Ar startCPU ,
153 does not map virtual CPUs to real CPUs.
156 .Cm map Ns Op Ns , Ns Ar startCPU
157 maps each virtual CPU to a real CPU starting with real CPU 0 or
162 locks all virtual CPUs to the real CPU specified by
165 Specify the amount of memory to be used by the kernel in bytes,
173 Lowercase versions of
179 Specify the number of CPUs you wish to emulate.
180 Up to 31 CPUs are supported.
181 The virtual kernel must be built with
183 to use this option and will default to 2 CPUs unless otherwise specified.
185 Specify a file in which to store the process ID.
186 A warning is issued if this file cannot be opened for writing.
188 Specify a R/W disk image
190 to be used by the kernel, with the first
200 option specified on the command line will be the boot disk.
202 Boot into single-user mode.
204 Enable writing to kernel memory and module loading.
205 By default, those are disabled for security reasons.
207 Turn on verbose booting.
210 A number of virtual device drivers exist to supplement the virtual kernel.
214 driver allows for up to 16
217 The root device will be
221 for further information on how to prepare a root image).
225 driver allows for up to 16 virtual CD-ROM devices.
226 Basically this is a read only
228 device with a block size of 2048.
229 .Ss Network interface
232 driver supports up to 16 virtual network interfaces which are associated with
237 device, the per-interface read only
240 .Va hw.vke Ns Em X Ns Va .tap_unit
241 holds the unit number of the associated
245 The virtual kernel only enables
249 while operating in regular console mode.
253 to the virtual kernel causes the virtual kernel to enter its internal
255 debugger and re-enable all other terminal signals.
258 to the virtual kernel triggers a clean shutdown by passing a
260 to the virtual kernel's
264 It is possible to directly gdb the virtual kernel's process.
265 It is recommended that you do a
266 .Ql handle SIGSEGV noprint
267 to ignore page faults processed by the virtual kernel itself.
269 A couple of steps are necessary in order to prepare the system to build and
270 run a virtual kernel.
271 .Ss Setting up the filesystem
274 architecture needs a number of files which reside in
276 Since these files tend to get rather big and the
278 partition is usually of limited size, we recommend the directory to be
281 partition with a link to it in
284 mkdir /home/var.vkernel
285 ln -s /home/var.vkernel /var/vkernel
288 Next, a filesystem image to be used by the virtual kernel has to be
289 created and populated (assuming world has been built previously):
291 dd if=/dev/zero of=/var/vkernel/rootimg.01 bs=1m count=2048
292 vnconfig -c -s labels vn0 /var/vkernel/rootimg.01
293 disklabel -r -w vn0s0 auto
294 disklabel -e vn0s0 # edit the label to create a vn0s0a partition
296 mount /dev/vn0s0a /mnt
298 make installworld DESTDIR=/mnt
300 make distribution DESTDIR=/mnt
301 echo '/dev/vkd0s0a / ufs rw 1 1' >/mnt/etc/fstab
302 echo 'proc /proc procfs rw 0 0' >>/mnt/etc/fstab
309 entry with the following line and turn off all other gettys.
311 console "/usr/libexec/getty Pc" cons25 on secure
314 Then, unmount the disk.
319 .Ss Compiling the virtual kernel
320 In order to compile a virtual kernel use the
322 kernel configuration file residing in
323 .Pa /usr/src/sys/config
324 (or a configuration file derived thereof):
327 make -DNO_MODULES buildkernel KERNCONF=VKERNEL
329 .Ss Enabling virtual kernel operation
332 .Va vm.vkernel_enable ,
333 must be set to enable
337 sysctl vm.vkernel_enable=1
339 .Ss Configuring the network on the host system
340 In order to access a network interface of the host system from the
342 you must add the interface to a
344 device which will then be passed to the
350 ifconfig bridge0 create
351 ifconfig bridge0 addm re0 # assuming re0 is the host's interface
354 .Ss Running the kernel
355 Finally, the virtual kernel can be run:
357 cd /usr/obj/usr/src/sys/VKERNEL
358 \&./kernel.debug -m 64m -r /var/vkernel/rootimg.01 -I auto:bridge0
363 command can be used to stop a virtual kernel.
364 .Sh BUILDING THE WORLD UNDER A VKERNEL
365 The virtual kernel platform does not have all the header files expected
366 by a world build, so the easiest thing to do right now is to specify a
367 pc32 target when building the world under a virtual kernel, like this:
369 vkernel# make MACHINE_PLATFORM=pc32 buildworld
370 vkernel# make MACHINE_PLATFORM=pc32 installworld
381 Virtual kernels were introduced in
386 thought up and implemented the
388 architecture and wrote the
395 This manual page was written by