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
18 Multiple devices may have a bootindex. The lowest bootindex is assigned to the
21 remaining boot devices to try.
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.
36 Booting without bootindex parameter
37 -----------------------------------
39 The QEMU guest firmware (the so-called s390-ccw bios) has also some rudimentary
40 support for scanning through the available block devices. So in case you did
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
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
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
76 the kernel names, so you only get a list without names here.
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
86 devices are assigned a ``bootindex`` and the ``loadparm`` is to be different
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
103 only used for devices with an assigned ``bootindex``. The machine ``loadparm``
104 is used when attempting to boot without a ``bootindex``.
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
124 The supported configuration file entries are ``DEFAULT``, ``LABEL``,