Booting as a z/VM guest from a DASD

6.10 z/VM guest

Boot Linux® by issuing the IPL command with a DASD boot device. You can specify additional parameters with the IPL command.

Before you begin

You need a DASD boot device prepared with zipl.

Procedure

Perform these steps to start the boot process:

  1. Establish a CMS or CP session with the z/VM® guest virtual machine where you want to boot Linux.
  2. Ensure that the boot device is accessible to your z/VM guest virtual machine.
  3. Issue a command of this form: 
    #cp i <devno> clear loadparm <parm> parm <kernel_parameters>
    where:
    <devno>
    Specifies the device number of the boot device as seen by the guest.
    loadparm <parm>
    Specifies an entry in a zipl boot menu, a site context, or both.
    Boot menu entry
    Applies only to menu configurations. Omit this specification if you are not addressing a menu configuration. If you have a menu configuration and omit this value, the default configuration might be used, or the menu might be displayed.
    To specify a boot menu entry, you can use one of the following values for <parm>:
    <i>
    Specifies the configuration number, which is a positive integer.
    0
    Specifies the default configuration.
    prompt
    Forces the menu to be displayed.

    When the menu is displayed, you can specify additional kernel parameters. These additional kernel parameters are appended to the parameters you might have provided in a parameter file. The combined parameter string must not exceed a length that is set when the kernel is compiled.

    For more information about menu configurations, see Menu configurations and sample configuration file.

    Site specification
    Applies only to Linux in a site-specific context, see Site-specific Linux instantiation. Omit this parameter if you are not working with site-specific sections in zipl environments or with site-specific DASD configurations.
    To specify a site, you can use one of the following values for <parm>:
    S<n>
    Specifies the site ID for which site-specific kernel parameters and DASD configurations are to be used. The site ID <n> is a digit in the range 0 to 9.
    SS
    Uses the subchannel set ID (SSID) of the IPL device as the site ID, for example, if the SSID is 0, values for site 0 are used.
    S
    Uses the common specifications. Specifying a single capital S without a trailing site ID is equivalent to omitting the S parameter.
    If you work with a combination of menu configurations and site specifications, append the site specification to the menu specification without a blank. For example, 3S2 selects the third zipl boot menu entry with the site 2 context.
    parm <kernel_parameters>
    is an optional 64-byte string of kernel parameters to be concatenated to the end of the existing kernel parameters used by your boot configuration.

DASD menu configuration example for z/VM

Use the VI VMSG z/VM CP command to choose a boot configuration from a menu configuration.

This example illustrates how menu2 in the sample configuration file in Menu configurations and sample configuration file is displayed on the z/VM guest virtual machine console:

00: zIPL interactive boot menu
00:
00:  0. default (boot1)
00:
00:  1. boot1
00:  2. boot3
00:
00: Note: VM users please use '#cp vi vmsg <input>'
00:
00: Please choose (default will boot in 30 seconds): #cp vi vmsg 2
You choose a configuration by specifying the configuration number. For example, to boot configuration boot3 specify 
#cp vi vmsg 2
You can also specify additional kernel parameters by appending them to the configuration number. For example, you can specify: 
#cp vi vmsg 2 maxcpus=1
These parameters are concatenated to the end of the existing kernel parameters that are used by your boot configuration when booting Linux.