Displaying information about the AP bus

6.10 LPAR mode z/VM guest KVM guest

Use the lszcrypt -b command to display status information about the AP bus; alternatively, you can use sysfs.

About this task

The AP bus is represented in sysfs as a directory of the form 
/sys/bus/ap
The sysfs directory contains a number of attributes with information about the AP bus.
Table 1. AP bus attributes
Attribute Explanation
ap_domain Read-write attribute that represents the default domain selected by the kernel. Alternatively, you can select the default domain using a kernel parameter.
ap_max_domain_id Read-only attribute that represents the largest possible domain ID. Domain IDs can range from 0 to this number, which depends on the mainframe model.
ap_control_domain_mask Read-only attribute that represents the installed control domain facilities as a 32-byte field in hexadecimal notation. A maximum number of 256 domains can be addressed. Each bit position represents a dedicated control domain.
ap_usage_domain_mask Read-only attribute that represents the installed usage domain facilities as a 32-byte field in hexadecimal notation. A maximum number of 256 domains can be addressed. Each bit position represents a usage domain.
ap_adapter_mask Read-only attribute that represents the installed cryptographic adapters as a 32-byte field in hexadecimal notation. A maximum number of 256 adapters (0-255) can be addressed. Each bit position represents an adapter.
ap_interrupts Read-only attribute that indicates whether interrupt handling for the AP bus is enabled.
apmask Read-write attribute that represents up to 256 cryptographic adapters. The attribute is a 64-digit hexadecimal representation of the 256-digit binary mask. In combination with the aqmask attribute, it marks a set of AP queues that are reserved for device drivers other than zcrypt. See Freeing AP queues for KVM guests.
aqmask Read-write attribute that represents 256 cryptographic domains. The attribute is a 64-digit hexadecimal representation of the 256-digit binary mask. In combination with the apmask attribute, it marks a set of AP queues that are reserved for device drivers other than zcrypt. See Freeing AP queues for KVM guests.
bindings Read-only attribute that shows which ratio of the available AP queues are bound to a device driver. The information has this format: <nr_of_bound_ap_queues>/<total_nr_of_ap_queues>. If all available AP queues are bound to a device driver, this ratio is appended with the string (complete). For example, with 8 AP queues, all of which are bound to a device driver, the attribute reads: 8/8 (complete).

This attribute indicates the progress of the adapter initialization process.
config_time Read-write attribute that represents a time interval in seconds used to detect new crypto devices.
features As of IBM z16, a read-only attribute that lists the hardware features of the AP bus. The following features are possible:
  • APSC - Extended TAPQ (Test AP Queue) support.
  • APXA - Support for more than 16 domains per card.
  • QACT - QACT support for toleration of new unknown crypto cards.
  • RC8A - Firmware reports 0x8A instead of 0x42 on some error conditions.
  • APSB - AP pass-through support for KVM guests running in secure-execution mode.
Example:
# cat /sys/bus/ap/features 
APSC APXA QACT RC8A APSB
poll_thread Read-write attribute that indicates whether polling for the AP bus is enabled. This attribute is not relevant to environments that support AP adapter interrupts, see AP adapter interrupts.
poll_timeout Read-write attribute that represents the time interval of the poll thread in nanoseconds. This attribute is not relevant to environments that support AP adapter interrupts, see AP adapter interrupts.
scans Reading this attribute shows the number of AP bus scans since the AP bus initialization. Writing to the attribute triggers a scan.

Example

# lszcrypt -b
ap_domain=0x6
ap_max_domain_id=0x54
ap_interrupts are enabled
config_time=30 (seconds)
poll_thread is disabled
poll_timeout=250000 (nanoseconds)