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

DISPLAY Guest Storage (z/Architecture)
storage without needing to know whether the program is currently in access
register mode. This is done automatically for you by CP.
5. If the BASEnn and INDEXnn operands are used together, the specified starting
address for display is used as a displacement from the address formed from
the sum of the contents of the two specified registers.
The values in the registers specified by the BASEnn and INDEXnn operands
are treated as 24-bit, 31-bit, or 64-bit real addresses according to the
addressing mode bits (EA and BA - bits 31 and 32) in the virtual machine’s
PSW. The addressing mode is determined as follows:
Bit 31 Bit 32 Addressing Mode
0 0 24-bit
0 1 31-bit
1 1 64-bit
6. During DISPLAY command processing, the authorization mechanisms used
during normal address translation are not used.
7. Special authorization is required to use the SPACE or ASIT operand of this
command to view any address space other the host-primary address space of
the virtual CPU. In order to use this command to display storage in an address
space, one of the following conditions must be satisfied:
v Your virtual machine must be the owner of the address space. Your virtual
machine is the owner of its host-primary address space and of any address
space that it creates using the CREATE function of the ADRSPACE macro.
v If the address space is owned by another virtual machine, your virtual
machine must have read-only or read-write authorization to the address
space. The owner of the address space can grant authorization to your
virtual machine using the PERMIT function of the ADRSPACE macro.
Authorization is granted on a space-by-space basis, so that you may be
authorized to view one address space of a virtual machine, but not to view a
different space.
8. The operands V and W used in displaying third-level storage from guest
primary and secondary are supported for compatibility. The PRI and SECO
operands replace the V and W operands.
9. When multiple DISPLAY requests are entered on a single line, the BASEnn
and INDEXnn operands are not applied to subsequent DISPLAY requests on
the command line. They must be explicitly entered for each DISPLAY request.
10. When the ASIT or SPACE operand is specified, the DISPLAY request will fail if
the specified address space does not exist, or if you are not authorized to
access the address space. The current request is rejected and processing of
the command line is terminated. The rejected operands are displayed along
with a message indicating the nature of the error.
11. The DISPLAY command requires an address-space-control element (ASCE) to
display third-level storage (storage that appears virtual to your virtual machine).
It may receive the ASCE as an operand, find it in a control register, or use the
access-register translation (ART) process or the address space number (ASN)
translation process to obtain the ASCE. The access-register translation and
ASN translation processes may fail because of one of several program
exception conditions. If the translation does not succeed, the current request is
rejected, and processing of the command line is terminated. The rejected
operands are displayed along with a response indicating the nature of the
exception condition.
Chapter 2. CP Commands 309