From: Jared Rossi Date: Fri, 15 Nov 2024 00:27:42 +0000 (-0500) Subject: docs/system/s390x/bootdevices: Update loadparm documentation X-Git-Tag: v9.2.0-rc1~6^2~8 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0271fdc650b212533b8aeaecbedfe8ccf6bbbef3;p=thirdparty%2Fqemu.git docs/system/s390x/bootdevices: Update loadparm documentation Update documentation to include per-device loadparm support. Signed-off-by: Jared Rossi Reviewed-by: Thomas Huth Message-ID: <20241115002742.3576842-1-jrossi@linux.ibm.com> Signed-off-by: Thomas Huth --- diff --git a/docs/system/s390x/bootdevices.rst b/docs/system/s390x/bootdevices.rst index 1a1a764c1c4..97b3914785a 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 + +If a ``loadparm`` is specified on both the machine and a device, the per-device +value will superseded the machine value.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