diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/system/bootindex.rst | 2 | ||||
| -rw-r--r-- | docs/system/s390x/bootdevices.rst | 24 |
2 files changed, 24 insertions, 2 deletions
diff --git a/docs/system/bootindex.rst b/docs/system/bootindex.rst index 988f7b3beb..5e1b33ee22 100644 --- a/docs/system/bootindex.rst +++ b/docs/system/bootindex.rst @@ -53,7 +53,7 @@ booting. For instance, the x86 PC BIOS boot specification allows only one disk to be bootable. If boot from disk fails for some reason, the x86 BIOS won't retry booting from other disk. It can still try to boot from floppy or net, though. In the case of s390x BIOS, the BIOS will try up to -8 total devices, any number of which may be disks. +8 total devices, any number of which may be disks or virtio-net devices. Sometimes, firmware cannot map the device path QEMU wants firmware to boot from to a boot method. It doesn't happen for devices the firmware 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 |