z/VM: CP Commands and Utilities Reference - z/VM - IBM

VARY PROCESSOR
VARY PROCESSOR
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VARY
Authorization
Purpose
Operands
ONline
OFFline
Usage Notes
PROCessor
Privilege Class: B
1708 z/VM: CP Commands and Utilities Reference
nn
Use VARY PROCESSOR to do the following:
v Enable or disable a processor for the control program (CP)
v Enable or disable a processor for the user.
ONline
OFFline
enables or disables the logical connection.
PROCessor nn
identifies the processor to be made available or unavailable. The value of nn is
the processor address (a hexadecimal value from 00 through 3F) established
when the processor is installed.
1. The VARY PROCESSOR command does not affect the connection of a Vector
Facility associated with the varied real processor. If the associated Vector
Facility is not connected at the time a VARY ONLINE PROCESSOR command
is entered, it is still not connected after the VARY command completes.
Conversely, if a Vector Facility is connected at the time that a VARY OFFLINE
PROCESSOR command is issued, it remains connected to its associated
processor even after that processor is varied offline.
2. When a VARY PROCESSOR or VARY VECTOR command affects a processor
dedicated to a preferred guest virtual CPU, rededication is attempted in order to:
v Keep real processors with Vector Facilities dedicated to preferred guest
virtual CPUs with Vector Facilities defined.
v Keep real processors without Vector Facilities dedicated to preferred guest
virtual CPUs with no Vector Facilities defined.
Dedication occurs whether or not the goals above can be accomplished.
3. If a virtual CPU with a Vector Facility defined is left without a real Vector Facility
available, subsequent vector instructions result in one of two guest interrupts:
v A vector operation exception presented to those guests that had not been
previously informed by CP that a real Vector Facility was available for their
use
v A Vector Facility failure machine check presented to those guests who had
been informed by CP that a real Vector Facility was available for their use.
These situations can occur as a result of VARY PROCESSOR, VARY VECTOR,
or changes in dedication. The system operator always receives a warning
message when such a circumstance arises.
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