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

DUMP Guest Storage (ESA/390)
v ALET 1 always indicates the current secondary address space designated
by the STD in guest control register 7, regardless of the current contents of
the dispatchable unit access list.
v Access register 0 is always treated as containing ALET 0. The contents of
access register 0 are not used during access register translation processing.
v General register 0 is always treated as containing the value 0 when used as
the base or index register. The contents of general register 0 are never
used.
6. The BASE operand is primarily intended to be used in conjunction with the L
operand. It lets you dump the storage used by the virtual machine in one less
step than would otherwise be possible. Without the BASE operand, you may
need to display the contents of a general register, add the displacement, and
then enter the DUMP command to examine storage the program is using. With
the use of access registers, the BASE option additionally lets you dump
storage without needing to know whether your program is currently in access
register mode. This is done automatically for you by CP.
7. If you use the BASEnn and INDEXnn operands together, the specified starting
address for a dump 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 or 31-bit real addresses according to the addressing
mode (A) bit in the virtual machine’s PSW. That is, if the A bit is 1, the value is
a 31-bit address. If the A bit is 0, the value is a 24-bit address.
8. During DUMP command processing, the authorization mechanisms used
during normal address translation are not used.
9. Special authorization is required to use the SPACE or ASIT operand of this
command to dump any address space other the host-primary address space of
the virtual CPU. In order to use this command to dump 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 dump one address space of a virtual machine but may not be
authorized to view a different space.
10. The operands V and W used in dumping third-level storage from guest primary
and secondary storage are supported for compatibility. The PRI and SECO
operands replace the V and W operands.
11. When the ASIT or SPACE operand is specified, the DUMP request fails 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.
12. The DUMP command requires a segment table designation (STD) to display
third-level storage (storage that appears virtual to your virtual machine). It may
receive the STD as an operand, find it in a control register, or use the
access-register translation (ART) or the address space number (ASN)
translation process to obtain the STD. The access-register translation and ASN
translation processes may fail because of one of several program exception
Chapter 2. CP Commands 371