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

Usage Notes
& indicates 64-bit address indirection. Indirection means that the contents of the
specified address are used instead of the address itself. In this case, the 64 bits
at the specified address are used as the new address for the Display command.
The indirect address specified here (following INDEX and BASE) is determined
after BASE and INDEX are applied.
A maximum of 16 indirection characters can be specified.
DISPLAY Guest Storage (ESA/XC)
1. Special authorization is required to use 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 may not be
authorized to view a different space.
2. When running with a saved segment, you can display storage locations outside
the range of your virtual machine size if they are within the saved segment. If
locations exist between the upper limit of your virtual machine and the address
at which the saved segment was saved, any attempt to display those locations
(or associated keys) causes the “nonaddressable storage” response to be
displayed.
3. The operands L, PRI, AREG, and ALET specify the host-access-register
translation (ART) process. The ART process performs special-case translation
processes for certain ALET values and access registers:
v The ALET X'00000000' always indicates the host-primary address space.
v Access register 0 is always treated as containing ALET X'00000000'. The
contents of access register 0 are not used during host-access-register
translation processing.
4. General register 0 is always treated as containing the value 0 when used as
the base or index register with the BASE or INDEX operands. The contents of
general register 0 are never used.
5. In the XC environment, special rules govern the conversion of real addresses
into absolute addresses. In some cases, prefixing is performed as usual to
convert a real address to an absolute address, while in other cases prefixing is
not performed and real addresses are treated unchanged as absolute
addresses.
These rules have an effect on the interpretation of the addresses that specify
the range of storage locations to be displayed:
v When storage is specified using the ALET or AREG operand and the ALET
value used is not X'00000000', prefixing is not performed on the addresses
that specify the range of storage in the target address space.
v When storage in the host-primary address space is specified by using the
PRI operand, or by using the ALET or AREG operand when the ALET value
Chapter 2. CP Commands 293