68 lines
3.0 KiB
Plaintext
68 lines
3.0 KiB
Plaintext
Normally, a minimal initrd is created automatically by the rcutorture
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scripting. But minimal really does mean "minimal", namely just a single
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root directory with a single statically linked executable named "init":
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$ size tools/testing/selftests/rcutorture/initrd/init
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text data bss dec hex filename
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328 0 8 336 150 tools/testing/selftests/rcutorture/initrd/init
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Suppose you need to run some scripts, perhaps to monitor or control
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some aspect of the rcutorture testing. This will require a more fully
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filled-out userspace, perhaps containing libraries, executables for
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the shell and other utilities, and soforth. In that case, place your
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desired filesystem here:
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tools/testing/selftests/rcutorture/initrd
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For example, your tools/testing/selftests/rcutorture/initrd/init might
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be a script that does any needed mount operations and starts whatever
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scripts need starting to properly monitor or control your testing.
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The next rcutorture build will then incorporate this filesystem into
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the kernel image that is passed to qemu.
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Or maybe you need a real root filesystem for some reason, in which case
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please read on!
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The remainder of this document describes one way to create the
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rcu-test-image file that contains the filesystem used by the guest-OS
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kernel. There are probably much better ways of doing this, and this
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filesystem could no doubt be smaller. It is probably also possible to
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simply download an appropriate image from any number of places.
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That said, here are the commands:
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------------------------------------------------------------------------
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dd if=/dev/zero of=rcu-test-image bs=400M count=1
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mkfs.ext3 ./rcu-test-image
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sudo mount -o loop ./rcu-test-image /mnt
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# Replace "precise" below with your favorite Ubuntu release.
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# Empirical evidence says this image will work for 64-bit, but...
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# Note that debootstrap does take a few minutes to run. Or longer.
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sudo debootstrap --verbose --arch i386 precise /mnt http://archive.ubuntu.com/ubuntu
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cat << '___EOF___' | sudo dd of=/mnt/etc/fstab
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# UNCONFIGURED FSTAB FOR BASE SYSTEM
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#
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/dev/vda / ext3 defaults 1 1
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dev /dev tmpfs rw 0 0
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tmpfs /dev/shm tmpfs defaults 0 0
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devpts /dev/pts devpts gid=5,mode=620 0 0
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sysfs /sys sysfs defaults 0 0
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proc /proc proc defaults 0 0
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___EOF___
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sudo umount /mnt
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------------------------------------------------------------------------
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References:
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http://sripathikodi.blogspot.com/2010/02/creating-kvm-bootable-fedora-system.html
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https://help.ubuntu.com/community/KVM/CreateGuests
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https://help.ubuntu.com/community/JeOSVMBuilder
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http://wiki.libvirt.org/page/UbuntuKVMWalkthrough
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http://www.moe.co.uk/2011/01/07/pci_add_option_rom-failed-to-find-romfile-pxe-rtl8139-bin/ -- "apt-get install kvm-pxe"
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https://www.landley.net/writing/rootfs-howto.html
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https://en.wikipedia.org/wiki/Initrd
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https://en.wikipedia.org/wiki/Cpio
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http://wiki.libvirt.org/page/UbuntuKVMWalkthrough
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