system/s390x/bootdevices.rst

1 Boot devices on s390x
5 --------------------------------
9 in s390x-speak -- IPL means "Initial Program Load").
15  qemu-system-s390x -drive if=none,id=dr1,file=guest.qcow2 \
16                    -device virtio-blk,drive=dr1,bootindex=1
20 lowest bootindex will be tried and so on until IPL is successful or there are no
23 For booting from a CD-ROM ISO image (which needs to include El-Torito boot
24 information in order to be bootable), it is recommended to specify a ``scsi-cd``
27  qemu-system-s390x -blockdev file,node-name=c1,filename=... \
28                    -device virtio-scsi \
29                    -device scsi-cd,drive=c1,bootindex=1
32 boot device. The old-fashioned ``-boot order=...`` command of QEMU (and
33 also ``-boot once=...``) is not supported on s390x.
37 -----------------------------------
39 The QEMU guest firmware (the so-called s390-ccw bios) has also some rudimentary
42 chance that it finds a bootable device on its own and starts a guest operating
48 This also means that you should avoid the classical short-cut commands like
49 ``-hda``, ``-cdrom`` or ``-drive if=virtio``, since it is not possible to
51 ``-cdrom`` option even does not give you a real (virtio-scsi) CD-ROM device on
53 virtio-blk device with this parameter instead, which might not be the right
55 recommended to specify a CD-ROM device via ``-device scsi-cd`` (as mentioned
60 ------------------------------------------------
62 The ``s390-ccw-virtio`` machine supports the so-called ``loadparm`` parameter
63 which can be used to select the kernel on the disk of the guest that the
64 s390-ccw bios should boot. When starting QEMU, it can be specified like this::
66  qemu-system-s390x -machine s390-ccw-virtio,loadparm=<string>
69 ``<string>`` here. In that case the s390-ccw bios will show a list of
70 installed kernels on the disk of the guest and ask the user to enter a number
71 to chose which kernel should be booted -- similar to what can be achieved by
72 specifying the ``-boot menu=on`` option when starting QEMU. Note that the menu
73 list will only show the names of the installed kernels when using a DASD-like
74 disk image with 4k byte sectors. On normal SCSI-style disks with 512-byte
75 sectors, there is not enough space for the zipl loader on the disk to store
80 shown when using the ``PROMPT`` option, and the s390-ccw bios will then try
82 Note that ``0`` can be used to boot the default entry. If the machine
83 ``loadparm`` is not assigned a value, then the default entry is used.
85 By default, the machine ``loadparm`` applies to all boot devices. If multiple
87 between them, an independent ``loadparm`` may be assigned on a per-device basis.
89 An example guest using per-device ``loadparm``::
91   qemu-system-s390x -drive if=none,id=dr1,file=primary.qcow2 \
92                    -device virtio-blk,drive=dr1,bootindex=1 \
93                    -drive if=none,id=dr2,file=secondary.qcow2 \
94                    -device virtio-blk,drive=dr2,bootindex=2,loadparm=3
96 In this case, the primary boot device will attempt to IPL using the default
101 If a ``loadparm`` is specified on both the machine and a device, the per-device
102 value will superseded the machine value.  Per-device ``loadparm`` values are
108 -----------------------------
111 for virtio-net-ccw devices.  The ``bootindex`` property is especially
117  qemu-system-s390x -netdev user,id=n1,tftp=...,bootfile=... \
118                    -device virtio-net-ccw,netdev=n1,bootindex=1
120 The network bootloader also has basic support for pxelinux.cfg-style
123 for details how to set up the configuration file on your TFTP server.
124 The supported configuration file entries are ``DEFAULT``, ``LABEL``,