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Diffstat (limited to 'docs/system/s390x/bootdevices.rst')
| -rw-r--r-- | docs/system/s390x/bootdevices.rst | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/docs/system/s390x/bootdevices.rst b/docs/system/s390x/bootdevices.rst index 1a1a764c1c..97b3914785 100644 --- a/docs/system/s390x/bootdevices.rst +++ b/docs/system/s390x/bootdevices.rst @@ -79,7 +79,29 @@ The second way to use this parameter is to use a number in the range from 0 to 31. The numbers that can be used here correspond to the numbers that are shown when using the ``PROMPT`` option, and the s390-ccw bios will then try to automatically boot the kernel that is associated with the given number. -Note that ``0`` can be used to boot the default entry. +Note that ``0`` can be used to boot the default entry. If the machine +``loadparm`` is not assigned a value, then the default entry is used. + +By default, the machine ``loadparm`` applies to all boot devices. If multiple +devices are assigned a ``bootindex`` and the ``loadparm`` is to be different +between them, an independent ``loadparm`` may be assigned on a per-device basis. + +An example guest using per-device ``loadparm``:: + + qemu-system-s390x -drive if=none,id=dr1,file=primary.qcow2 \ + -device virtio-blk,drive=dr1,bootindex=1 \ + -drive if=none,id=dr2,file=secondary.qcow2 \ + -device virtio-blk,drive=dr2,bootindex=2,loadparm=3 + +In this case, the primary boot device will attempt to IPL using the default +entry (because no ``loadparm`` is specified for this device or for the +machine). If that device fails to boot, the secondary device will attempt to +IPL using entry number 3. + +If a ``loadparm`` is specified on both the machine and a device, the per-device +value will superseded the machine value. Per-device ``loadparm`` values are +only used for devices with an assigned ``bootindex``. The machine ``loadparm`` +is used when attempting to boot without a ``bootindex``. Booting from a network device |