IBM AIX Continuous Availability Features - IBM Redbooks

might share a given hardware key. Most kernel keys are for use only within the kernel (the full
list can be found in sys/skeys.h). Table 3-4 shows the kernel keys that are likely to be useful to
kernel extension developers.
Table 3-4 Useful kernel keys
Key name Description
KKEY_PUBLIC This kernel key is always necessary for access to a program's stack, bss,
and data regions. Data allocated from the pinned_heap and the
kernel_heap is also public.
KKEY_BLOCK_DEV This kernel key is required for block device drivers. Their buf structs must
be either public or in this key.
KKEY_COMMO This kernel key is required for communication drivers. CDLI structures must
be either public or in this key.
KKEY_NETM This kernel key is required for network and other drivers to reference
memory allocated by net_malloc.
KKEY_USB This kernel key is required for USB device drivers.
KKEY_GRAPHICS This kernel key is required for graphics device drivers.
KKEY_DMA This kernel key is required for DMA information (DMA handles and EEH
handles).
KKEY_TRB This kernel key is required for timer services (struct trb).
KKEY_IOMAP This kernel key is required for access to I/O-mapped segments.
KKEY_FILE_SYSTEM This kernel key is required to access vnodes and gnodes (vnop callers).
Note: Table 3-4 shows a preliminary list of kernel keys. As kernel keys are added to
components, additional kernel keys will be defined.
The current full list can be found in /usr/include/sys/skeys.h.
Kernel keysets
Note: Not all keys in the kernel key list are currently enforced. However, it is always safe to
include them in a keyset.
Because the full list of keys might evolve over time, the only safe way to pick up the set of
keys necessary for a typical kernel extension is to use one of the predefined kernel keysets,
as shown the following list.
KKEYSET_KERNEXT The minimal set of keys needed by a kernel extension.
KKEYSET_COMMO Keys needed for a communications or network driver.
KKEYSET_BLOCK Keys needed for a block device driver.
KKEYSET_GRAPHICS Keys needed for a graphics device driver.
KKEYSET_USB Keys needed for a USB device driver.
See sys/skeys.h for a complete list of the predefined kernel keysets. These keysets provide
read and write access to the data protected by their keys. If you want simply read access to
keys, those sets are named by appending _READ (as in KKEYSET_KERNEXT_READ).
82 IBM AIX Continuous Availability Features