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32 .\" $DragonFly: src/share/man/man7/vkernel.7,v 1.9 2007/02/04 17:24:56 dillon Exp $
39 .Nd virtual kernel architecture
45 .Pa /usr/obj/usr/src/sys/VKERNEL/kernel.debug
47 .Op Fl e Ar name Ns = Ns Li value : Ns Ar name Ns = Ns Li value : Ns ...
49 .Op Fl I Ar interface Ns Op Ar :address1 Ns Oo Ar :address2 Oc Ns Oo Ar /netmask Oc
55 architecture allows for running
59 The following options are available:
60 .Bl -tag -width ".Fl m Ar size"
61 .It Fl e Ar name Ns = Ns Li value : Ns Ar name Ns = Ns Li value : Ns ...
62 Specify an environment to be used by the kernel.
64 .\"Specify a memory image
66 .\"to be used by the kernel.
67 .It Fl I Ar interface Ns Op Ar :address1 Ns Oo Ar :address2 Oc Ns Oo Ar /netmask Oc
68 Create a virtual network device, with the first
78 argument is the name of a
83 path prefix does not have to be specified and will be automatically prepended.
86 will pick the first unused
94 arguments are the IP addresses of the
105 interface is added to the specified
111 argument applies to all interfaces for which an address is specified.
113 Specify the amount of memory to be used by the kernel in bytes,
121 Lowercase versions of
127 Specify the root image
129 to be used by the kernel.
132 for further information on how to prepare a root image.
134 Boot into single-user mode.
136 Enable writing to kernel memory and module loading.
137 By default, those are disabled for security reasons.
139 Turn on verbose booting.
142 The virtual kernel enables all terminal signals while in
144 mode but only enables
147 while operating as a console which causes the virtual kernel to enter its
152 A couple of steps are necessary in order to prepare the system to build and
153 run a virtual kernel.
154 .Ss Setting up the filesystem
157 architecture needs a number of files which reside in
159 Since these files tend to get rather big and the
161 partition is usually of limited size, we recommend the directory to be
164 partition with a link to it in
167 mkdir /home/var.vkernel
168 ln -s /home/var.vkernel /var/vkernel
171 Next, a filesystem image to be used by the virtual kernel has to be
172 created and populated (assuming world has been built previously):
174 dd if=/dev/zero of=/var/vkernel/rootimg.01 bs=1m count=2048
175 vnconfig -c -s labels vn0 /var/vkernel/rootimg.01
176 disklabel -r -w vn0 auto
177 disklabel -e vn0 # edit the label to create a vn0a partition
181 make installworld DESTDIR=/mnt
183 make distribution DESTDIR=/mnt
184 echo '/dev/vkd0a / ufs rw 1 1' >/mnt/etc/fstab
185 echo 'console "/usr/libexec/getty Pc" cons25 on secure' >/mnt/etc/ttys
189 .Ss Compiling the virtual kernel
190 In order to compile a virtual kernel use the
192 kernel configuration file residing in
193 .Pa /usr/src/sys/config
194 (or a configuration file derived thereof):
197 make -DNO_MODULES buildkernel KERNCONF=VKERNEL
199 .Ss Enabling virtual kernel operation
202 .Va vm.vkernel_enable ,
203 must be set to enable
207 sysctl vm.vkernel_enable=1
209 .Ss Configuring the network on the host system
210 In order to access a network interface of the host system from the
212 you must add the interface to a
214 device which will then be passed to the
220 ifconfig bridge0 create
221 ifconfig bridge0 addm re0 # assuming re0 is the host's interface
224 .Ss Running the kernel
225 Finally, the virtual kernel can be run:
227 cd /usr/obj/usr/src/sys/VKERNEL
228 \&./kernel.debug -m 64m -r /var/vkernel/rootimg.01 -I auto:bridge0
233 command can be used to stop a virtual kernel.
234 .Ss Debugging the kernel
235 It is possible to directly gdb the virtual kernel's process. It is
236 recommended that you do a 'handle SIGSEGV noprint' to ignore page faults
237 taken by the virtual kernel itself (which it processes itself).
247 Virtual kernels were introduced in
252 thought up and implemented the
255 This manual page was written by