1 Normally, a minimal initrd is created automati 1 Normally, a minimal initrd is created automatically by the rcutorture
2 scripting. But minimal really does mean "mini 2 scripting. But minimal really does mean "minimal", namely just a single
3 root directory with a single statically linked 3 root directory with a single statically linked executable named "init":
4 4
5 $ size tools/testing/selftests/rcutorture/init 5 $ size tools/testing/selftests/rcutorture/initrd/init
6 text data bss dec hex filena 6 text data bss dec hex filename
7 328 0 8 336 150 tools/ 7 328 0 8 336 150 tools/testing/selftests/rcutorture/initrd/init
8 8
9 Suppose you need to run some scripts, perhaps 9 Suppose you need to run some scripts, perhaps to monitor or control
10 some aspect of the rcutorture testing. This w 10 some aspect of the rcutorture testing. This will require a more fully
11 filled-out userspace, perhaps containing libra 11 filled-out userspace, perhaps containing libraries, executables for
12 the shell and other utilities, and soforth. I 12 the shell and other utilities, and soforth. In that case, place your
13 desired filesystem here: 13 desired filesystem here:
14 14
15 tools/testing/selftests/rcutorture/ini 15 tools/testing/selftests/rcutorture/initrd
16 16
17 For example, your tools/testing/selftests/rcut 17 For example, your tools/testing/selftests/rcutorture/initrd/init might
18 be a script that does any needed mount operati 18 be a script that does any needed mount operations and starts whatever
19 scripts need starting to properly monitor or c 19 scripts need starting to properly monitor or control your testing.
20 The next rcutorture build will then incorporat 20 The next rcutorture build will then incorporate this filesystem into
21 the kernel image that is passed to qemu. 21 the kernel image that is passed to qemu.
22 22
23 Or maybe you need a real root filesystem for s 23 Or maybe you need a real root filesystem for some reason, in which case
24 please read on! 24 please read on!
25 25
26 The remainder of this document describes one w 26 The remainder of this document describes one way to create the
27 rcu-test-image file that contains the filesyst 27 rcu-test-image file that contains the filesystem used by the guest-OS
28 kernel. There are probably much better ways o 28 kernel. There are probably much better ways of doing this, and this
29 filesystem could no doubt be smaller. It is p 29 filesystem could no doubt be smaller. It is probably also possible to
30 simply download an appropriate image from any 30 simply download an appropriate image from any number of places.
31 31
32 That said, here are the commands: 32 That said, here are the commands:
33 33
34 ---------------------------------------------- 34 ------------------------------------------------------------------------
35 dd if=/dev/zero of=rcu-test-image bs=400M coun 35 dd if=/dev/zero of=rcu-test-image bs=400M count=1
36 mkfs.ext3 ./rcu-test-image 36 mkfs.ext3 ./rcu-test-image
37 sudo mount -o loop ./rcu-test-image /mnt 37 sudo mount -o loop ./rcu-test-image /mnt
38 38
39 # Replace "precise" below with your favorite U 39 # Replace "precise" below with your favorite Ubuntu release.
40 # Empirical evidence says this image will work 40 # Empirical evidence says this image will work for 64-bit, but...
41 # Note that debootstrap does take a few minute 41 # Note that debootstrap does take a few minutes to run. Or longer.
42 sudo debootstrap --verbose --arch i386 precise 42 sudo debootstrap --verbose --arch i386 precise /mnt http://archive.ubuntu.com/ubuntu
43 cat << '___EOF___' | sudo dd of=/mnt/etc/fstab 43 cat << '___EOF___' | sudo dd of=/mnt/etc/fstab
44 # UNCONFIGURED FSTAB FOR BASE SYSTEM 44 # UNCONFIGURED FSTAB FOR BASE SYSTEM
45 # 45 #
46 /dev/vda / ext3 defaul 46 /dev/vda / ext3 defaults 1 1
47 dev /dev tmpfs rw 47 dev /dev tmpfs rw 0 0
48 tmpfs /dev/shm tmpfs defaul 48 tmpfs /dev/shm tmpfs defaults 0 0
49 devpts /dev/pts devpts gid=5, 49 devpts /dev/pts devpts gid=5,mode=620 0 0
50 sysfs /sys sysfs defaul 50 sysfs /sys sysfs defaults 0 0
51 proc /proc proc defaul 51 proc /proc proc defaults 0 0
52 ___EOF___ 52 ___EOF___
53 sudo umount /mnt 53 sudo umount /mnt
54 ---------------------------------------------- 54 ------------------------------------------------------------------------
55 55
56 56
57 References: 57 References:
58 58
59 http://sripathikodi.blogspot.com/2010/ 59 http://sripathikodi.blogspot.com/2010/02/creating-kvm-bootable-fedora-system.html
60 https://help.ubuntu.com/community/KVM/ 60 https://help.ubuntu.com/community/KVM/CreateGuests
61 https://help.ubuntu.com/community/JeOS 61 https://help.ubuntu.com/community/JeOSVMBuilder
62 http://wiki.libvirt.org/page/UbuntuKVM 62 http://wiki.libvirt.org/page/UbuntuKVMWalkthrough
63 http://www.moe.co.uk/2011/01/07/pci_ad 63 http://www.moe.co.uk/2011/01/07/pci_add_option_rom-failed-to-find-romfile-pxe-rtl8139-bin/ -- "apt-get install kvm-pxe"
64 https://www.landley.net/writing/rootfs 64 https://www.landley.net/writing/rootfs-howto.html
65 https://en.wikipedia.org/wiki/Initrd 65 https://en.wikipedia.org/wiki/Initrd
66 https://en.wikipedia.org/wiki/Cpio 66 https://en.wikipedia.org/wiki/Cpio
67 http://wiki.libvirt.org/page/UbuntuKVM 67 http://wiki.libvirt.org/page/UbuntuKVMWalkthrough
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