Linux diagnose code use

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SUSE Linux™ Enterprise Server 12 SP4 for IBM Z issues several diagnose instructions to the hypervisor (LPAR or z/VM®).

Table 1 lists all diagnoses that are used by the Linux kernel or a kernel module.

Linux can fail if you change the privilege class of the diagnoses marked as required by using the MODIFY diag command in z/VM.

Table 1. Linux diagnoses
Number Description Linux use Required/Optional
0x008 z/VM CP command console interface
  • The vmcp command
  • The 3215 and 3270 console drivers
  • The z/VM recording device driver (vmlogrdr)
  • smsgiucv
 Required
0x010 Release pages CMM Required
0x014 Input spool file manipulation The vmur device driver Required
0x044 Voluntary time-slice end In the kernel for spinlock and udelay Required
0x064 Allows Linux to attach a DCSS The DCSS block device driver (dcssblk), and the MONITOR record device driver (monreader). Required
0x09c Voluntary time slice yield Spinlock. Optional
0x0dc Monitor stream The APPLDATA monitor record and the MONITOR stream application support (monwriter). Required
0x204 LPAR Hypervisor data The hypervisor file system (hypfs). Required
0x210 Retrieve device information
  • The common I/O layer
  • The DASD driver DIAG access method
  • DASD read-only query
  • The vmur device driver
 Required
0x224 CPU type name table The hypervisor file system (hypfs). Required
0x250 Block I/O The DASD driver DIAG access method. Required
0x258 Page-reference services In the kernel, for pfault. Optional
0x288 Virtual machine time bomb The watchdog device driver. Required
0x2fc Hypervisor cpu and memory accounting data The hypervisor file system (hypfs). Required
0x308 Re-ipl Re-ipl and dump code. Required
0x500 Virtio functions Operate virtio-ccw devices Required
Draft comment: hweber
Also 0x26c ?

Required means that a function is not available without the diagnose; optional means that the function is available but there might be a performance impact.